American Arachnological Society - Portland 2011


	35th Annual Meeting of the American Arachnological Society July 8-11th 2011 in Portland, Oregon Hosted by Greta Binford at Lewis & Clark College and Susan Masta at Portland State University
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Molecular and biomechanical insights into the parallel origin of orb-like webs in spiders
Ingi Agnarsson	University of Puerto Rico Biology San Juan, Puerto Rico
Dakota Piorkowski	University of Akron Biology Akron, OH USA
Matja Gregori	Slovenian Academy of Sciences and Arts Jovan Hadzi Institute of Biology Ljubljana, Slovenia
Matja Kuntner	Slovenian Academy of Sciences and Arts Jovan Hadzi Institute of Biology Ljubljana, Slovenia
Todd A Blackledge	University of Akron Biology Akron, OH USA
The evolutionary origin of the spider orb web in Orbiculaiae was accompanied by new spinning behaviors and significant changes in the material properties of silk. In particular, the major ampullate silk that forms the backbones of most webs is stronger and stiffer among orb-weaving spiders, possibly facilitating the capture of flying insect prey. However, the little known Fecenia also constructs a two-dimensional aerial web that is strikingly similar to an orb web. Here, we first test the evolutionary affinity of the pseudo orb versus genuine orb webs and then compare the material properties of their silks. We sample two Fecenia and one Psechrus species (both in Psechridae) and sequence partial fragments of mitochondrial (16S, COI) and nuclear (18S, 28S, H3, wingless) markers, adding these data to the published orbicularian and RTA matrices to infer their phylogenetic affinities using Bayesian inference. We also perform tensile tests on the radii from both types of webs to compare their material properties in a broader evolutionary context.
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Dispersal biogeography: the role of dispersal in the generation of biodiversity
Ingi Agnarsson	University of Puerto Rico Biology San Juan, Puerto Rico
Matjaz Kuntner	Institute of Biology Slovenian Academy of Arts and Sciences Ljubljana, Slovenia
Oceanic islands are convenient models for studying dispersal and understanding how dispersal ability relates to speciation. We discuss recent studies of three nephilid lineages in the Indian Ocean (Clitaetra, Nephilengys, Nephila), representing poor, intermediate, and excellent dispersers, respectively. Based on these lineages, and empirical examples from other clades, we present a simple conceptual model of dispersal biogeography predicting that species richness of lineages across archipelagos should peak at intermediate dispersal ability. We also discuss likely skew towards high richness of intermediate-poor dispersers on Wallacean (fragment) islands such as the Greater Antilles in the Caribbean, and a skew towards high richness of intermediate-excellent dispersers on Darwinian (‘de novo’) islands, such as Hawaii. We conclude that although the processes underlying contemporary patterns of diversity on islands are many and complex, some broad patterns can be predicted by very simple models.
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Several new species of silhouettelloid goblin spiders of Madagascar (Araneae, Oonopidae).
Fernando Alvarez-Padilla	Universidad Nacional Autonoma de Mexico Biologia Comparada Mexico City
Darrell Ubick	California Academy of Sciences Entomology San Francisco, CA
Charles Griswold	California Academy of Sciences Entomology San Francisco, CA
Currently goblin spiders are subject to considerable taxonomic research by a large group of colleagues in many countries as part of the Planetary Biodiversity Inventory (PBI). The work presented here contributes to this effort to document and describe oonopid diversity world wide. We describe a total of nine species from Madagascar and the Seychelles documented with ca. 390 compound digital images and 670 scanning electron microscope pictures. These species represent two genera: Silhouettella Benoit, 1979 characterized by the absence of leg spines, eyes well developed occupying three quarters of the cephalothorax width and abdomen completely covered with scuta, and the new genus characterized by a gradual reduction of eyes, presence of leg spines and abdominal scuta. All species are new except Silhouettella curieusei the type of this genus which is only known from the Seychelles. The core of the taxonomic descriptions was done automatically by coding character observations to the PBI website using only a Internet browser and based mainly on the images mentioned above. The geographic distribution for all specimens was added to the PBI Database for Entering Collection Data (DEC) web interface. All of this information will be available online through the species pages of the PBI goblin spider website after the species descriptions are published. In addition, we used a novel feature of this taxonomic descriptive data base to export a phylogenetic data matrix of 1,173 taxa and 450 characters. A phylogenetic analysis with a subset of 543 taxa and 361 non redundant characters between sexes recovered these nine Malagasy species as two different clades: the former including S. curieusei plus two new species, and the latter including six new species. We emphasize that the character scoring for this 1,100+ species data set represents a collaborative effort of the PBI team of researchers, postdoctoral fellows and graduate students.
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Antimicrobial properties using egg cases for Theridiidae spiders Latrodectus hesperus and Latrodectus geometricus
Janet Andrade	California State University Fullerton Biological Science Fullerton, CA USA
Hector Sandoval
Merri L Casem	California State University Fullerton Biological Science Fullerton, CA USA
Spider egg cases function to protect developing spiderlings. Among its many characteristics, the silk that makes up the egg case appears to have antimicrobial properties. We report here on a preliminary analysis of the antimicrobial properties of egg case silk from the Theridiidae spiders Latrodectus hesperus and Latrodectus geometricus. Egg cases were collected from spiders that were housed in the lab. Egg cases were frozen to arrest development. Eggs or spiderlings were removed and separated from the silk. To test for the presence of bacterial floral small samples of the egg case silk were aseptically transferred to test tubes containing tryptic soy broth. Bacterial growth was monitored for a period of a week using optical density measurements. The majority of egg case samples from L. hesperus did not show any evidence of bacterial growth. In contrast the majority of samples from L. geometricus did give rise to bacterial growth. The presence of bacteria on the silk surface was also examined by repeatedly touching a silk sample to the surface of a tryptic soy agar plate. Colony formation did not occurred after 48 hours for both type of species with a much greater rate of colony formation for geometricus vs. hersperus. Silks from Araneidae spiders have been shown to have multiple surfaces layers. We hope to identify the factors responsible for the antimicrobial properties we have observed.
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The depths of divergence: A phylogenetic analysis of troglomorphic spiders in the genus Usofila (Araneae, Telemidae)
Tracy Audisio	California Academy of Sciences Entomology San Francisco, CA
Joel Ledford	California Academy of Sciences Entomology San Francisco, CA
Charles Griswold	California Academy of Sciences Entomology San Francisco, CA
Spiders in the genus Usofila thrive in cold, moist, dark microhabitats and are exapted for life in caves. Cave obligate, or troglobiotic, Usofila exhibit a suite of troglomorphic characters, however, species delimitation is problematic due to a high degree of morphological homogeneity. Although these taxa lack traditional diagnostic characters, they have evolved deep molecular divergence. The evolution of troglobionts can be explained either by the Climatic Relict Hypothesis (CRH) or by the Adaptive Shift Hypothesis (ASH). According to the CRH, troglobionts are relicts of a previously widespread fauna. A climatic shift occurred which pushed these species into caves. Alternatively, the ASH predicts a shift to the troglobiotic lifestyle prompted by resource availability. We used a combination of morphological and molecular data to assess species limits within Usofila and to test hypotheses for the evolution of troglobionts. Scanning electron microscopy and automontage were used to assess morphological variation, including both somatic and genitalic characters. Our molecular data is based on 28S rDNA and CO1 mtDNA from a sample of 51 individuals. Parsimony, Maximum Likelihood, and Bayesian analyses were used to estimate phylogenetic relationships and trait data were mapped on the resulting trees. Independent analysis of CO1 resulted in strong support for several terminal groups but was unable to resolve the deeper relationships. A concatenated analysis resolved the deeper relationships and suggested that there are eight new species of Usofila in California and that troglobionts have evolved independently on three occasions, which is consistent with the ASH hypothesis.
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High-throughput expression profiling of silk glands in the Western black widow, Latrodectus hesperus (Theridiidae)
Nadia A Ayoub	Washington and Lee University Biology Lexington, VA USA
Jessica E Garb	University of Massachusetts Lowell Biological Sciences Lowell, MA
Alex K Lancaster	Whitehead Institute for Biomedical Research Cambridge, MA USA
Cheryl Y Hayashi	University of California Riverside Biology Riverside, CA USA
Among silk producing organisms, spiders are unparalleled in their reliance on silk and the diversity of silk functions found both within and among species. Most spiders have multiple silk gland types with each type synthesizing a high-performance, task specific fiber or glue. For example, dragline silk, which originates in the major ampullate glands, has a tensile strength comparable to steel, and prey wrapping silk, which originates in the aciniform glands, is incredibly tough. Molecular studies of spider silks have almost entirely focused on the sequences of the component structural proteins (fibroins) and, hence, virtually all models of spider silk evolution and mechanical function are based solely on the attributes of fibroins. However, the spider silk system must involve fibroin as well as non-fibroin genes. Furthermore, the relative expression level of each of these genes, which should contribute to the diversity of spider silks, is largely unknown. We are using high-throughput sequencing to identify the major elements and their putative functions within the gene repertoire underlying silk synthesis in cob-web weaving spiders (Theridiidae), focusing on Western black widows, Latrodectus hesperus, and two closely related species. Preliminary results identified the fibroins and non-fibroins that are significantly more abundant in major ampullate glands compared to non-silk tissues. Furthermore, we found notable variation in the relative proportions of fibroin genes between two individuals commensurate with their readiness to build eggsacs. We will expand profiling to each of the silk gland types, and to other species, to further understand the diversification of silk functions.
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The goblin spider genus Opopaea and its distribution pattern on the Caribbean and the Pacific Islands (Araneae: Oonopidae).
Barbara C Baehr
The goblin spider genus Opopaea is a pantropical genus but only four species are widely distributed. O. deserticola Simon, 1891 and O. concolor (Blackwall, 1859) have their major distribution in Middle America especially on the Caribbean Islands whereas O. foveolata Roewer, 1963 and E. apicalis Simon, 1893 occur primarily on the Pacific Islands. E. apicalis is in fact an Opopaea species but not synonymised yet. Three new Opopaea species may be short range endemics and were found only on certain Pacific Islands. O. BB127 is recorded from Fiji together with O. foveolata and O. BB134 occurs on Hawaii, sympatric with E. apicalis. O. BB135 closely related to E. apicalis is reported from the Caroline Islands sympatric with E. apicalis and O. foveolata. All Caribbean and Pacific Islands are populated by not more than three Opopaea species with the exception of New Caledonia which has an extremely rich Opopaea fauna with 15 species of which 13 species are new to science.
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Reproductive output under threat of predation in the wolf spider, Schizocosa ocreata (Hentz)
Zeynep Benderlioglu
George Keeney
Andrew Roberts	The Ohio State University Evolution Ecology and Organismal Biology Newark, OH USA
Exposure to environmental and genetic stressors during development has adverse consequences on physical growth, physiology, and behavior of individuals. One common environmental stressor is exposure to predators. Nonhuman animals have evolved adaptive mechanisms to avoid being eaten while optimizing reproductive function during predation risk. The current project investigates maternal exposure to predation risk and reproductive outcome in the wolf spider, Schizocosa ocreata (Araneae: Lycosidae). Mature S. ocreata females were either maintained in standard laboratory conditions (Non-Stressed; NS), or with exposure to silk and chemical cues from the generalist wolf spider predator Hogna helluo (Araneae: Lycosidae) for 12 days after mating (Hogna-Stressed; HS). Reproductive behaviors were assessed regarding eggsac production and clutch size. Results show that HS females had less variability in clutch size compared to NS females and that clutch size increased marginally. Whereas none of the HS females produced an eggsac during the 12-day stress period, NS females did so as early as 2 days after mating. Similarly, none of the HS females dropped an eggsac before reaching the minimum incubation period (28 days), whereas 50% of NS females did. All but one female in each group produced at least a second eggsac from the single mating trial. However, only those from HS females resulted in surviving offspring. Our results suggest that exposure to predation risk during egg development increases reproductive performance in S. ocreata and is associated with enhanced fitness as evidenced by increased clutch size and offspring survival.
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Messing with morphogenesis in early spider development
Steve Black
Christine Bates
Kay Larkin	Reed College Biology Portland, OR USA
Molly Radany
Crystal Chaw
Two large-scale cell migrations occur during early spider development, and only spider embryos do them both. The first is the migration of a small cluster of cells, the cumulus, from the center to the edge of the germ disc. We labeled the cumulus cells with fluorescent dye and determined that their fate is opisthosomal, probably gut diverticula. Next, we experimentally tested whether or not the cumulus is required for normal development by surgically removing the cumulus cells in Zygiella x-notata embryos. The operated embryos develop grossly defective germ bands, confirming an important signaling role for the cumulus cells. The second large-scale cell migration occurs days later, at the germ band stage, and is called inversion. Inversion occurs when the germ band splits down the ventral midline and the left and right halves migrate away from each other. We find that inversion proceeds normally in Z. x-notata embryos if the yolk cell is poisoned, suggesting that the ‘motor’ for inversion is in the germ band itself. We think that cell division is part of the motor, because experimentally inhibiting cell division blocks inversion.
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In pursuit of the forces that drive sexual display divergence in closely related jumping spiders
Gwylim S Blackburn
Wayne P Maddison	University of British Columbia Zoology Vancouver, BC Canada
Sexual display traits often comprise the greatest phenotypic differences among even closely related species. This indicates the forces shaping sexual displays are a rich source of biological diversity and may play a role in speciation. Describing these forces at the earliest stages of display divergence is key to understanding how they affect diversification. We take up this challenge in a set of H. americanus jumping spider populations that are diverging in male sexual display morphology. We document generally weak genetic differentiation among populations and a regional pattern of increasing genetic isolation by geographic distance. These results suggest that selection in the face of gene flow, rather than genetic drift among isolated demes, underlies display divergence in this system. We also observe surprisingly low genetic differentiation between the H. americanus populations and that of a nearby congener, H. sansonii, raising the possibility that this second species provides a source of divergent selection or genetic variation for H. americanus.
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Protein intake as a constraint on spider silk expression.
Sean J Blamires	Tunghai University Life Science Taichung, Taiwan
Chun-Lin Wu
I-Min Tso	Tunghai University Life Science Taichung, Taiwan
An understanding of the various constraints on spider silk synthesis would assist in devising mechanisms for producing high performance silk analogues. The spidroins that make up spider major ampullate (MA) silk, MaSp1 and MaSp2, differ in proline content. Proline is energetically expensive to synthesize so it might be preferential for spiders that express high proline MaSp2 predominant silk to get most of their proline from food and switch MaSp expression when protein intake is low. We fed three orb spiders; Argiope aetherea, Cyrtophora moluccensis and Leucauge blanda, high protein (HP), low protein (LP) or no protein (NP) solutions. A. aetherea and L. blanda MA silks predominantly are principally comprised of the high proline MaSp2, while C. moluccesnsis MA silks are low in proline. After 10 days of feeding, silk amino acid compositions and mechanics were analyzed. The proline and glutamine compositions of A. aetherea and L. blanda silks decreased with protein intake, while amino acid compositions were less affected by protein intake in C. moluccensis silks. The expression of MaSp2 silks thus is constrained by protein intake. Protein intake indirectly affected silk strength and extensibility via proline content. The switch from expressing silks of predominantly MaSp2 to expressing silks of predominantly MaSp1 by A. aetherea and L. blanda when protein intake was reduced is indicative of a protein intake constraint over silk expression. The low proline silks of C. moluccensis are however relinquished of this protein intake constraint. Most orb web spiders have MA silks of a high proline composition because expressing MaSp2 endows their webs extensibility. Spiders that build three dimensional webs however express MaSp1 predominant silk and are free of the protein constraint. We propose that alleviation of the protein constraint may be an evolutionary force driving spider web three-dimensionality.
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Social Interactions in the colonial Mygalomorph Heterothele villosella (Strand 1907)
Jennifer M Bosco	College of the Holy Cross Biology Worcester, MA
Brian Moskalik	College of the Holy Cross Biology Worcester, MA
Spiders are normally solitary animals, infrequently engaging in contact with conspecifics. In rare circumstances, species abandon their solitary tendencies and remain in a group. Extreme inbreeding, reduced genetic diversity, high colony turnover rates and high rates of extinction potentially account for the rarity of this phenomenon. A potentially useful subject for addressing the evolution of spider (Mygalomorph) sociality is the Ischnocolid tarantula species Heterothele villosella. The social lifestyle of this species is not unique among its congeners but not all of them have been documented for sociality. Herein, we aim to examine fundamental social interactions and how environmental conditions influence this species’ sociality. This understanding will contribute to the growing body of knowledge pertaining to the evolution of spider sociality and how the assembly of these communities affects the evolution of competition and social living in an otherwise solitary animal. Initial observations suggest that cannibalism increases directly with incidences of contact when there are no established territories. We can postulate that dispersal, either natural or stochastic, may lead to increased rates of cannibalism in nature. After a brief acclimation period, individuals were observed to establish individual retreats/territories. During this phase, we observed social tolerance among individuals living in adjacent and shared retreats, greatly reducing the instances of cannibalism. Therefore, the observed colonial nature of the species may be impacted by familiarity/residency duration and overall environmental stability.
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Variation among individuals and life stages of Araneus diadematus in ultraviolet-induced fluorescence
Erin E Brandt
Susan E Masta	Portland State University Biology Portland, OR USA
Spiders have previously been shown to possess externally-expressed fluorescence. Different species of spiders were found to vary in the degree to which adult females fluoresced under ultraviolet light. However, it is not known whether fluorescence expression varies over the course of a spider’s life, or among individuals within a species. We developed new equipment and techniques to more precisely induce and quantify fluorescence intensity. We are currently quantifying ultraviolet-induced fluorescence of Araneus diadematus across each of its life stages. Spiders from different clutches and different molt stages were illuminated with different wavelengths of ultraviolet light. We chose wavelengths that are present in the sun’s spectrum and to which A. diadematus is commonly exposed. Images were captured with a digital camera, and pixel intensity was analyzed. We discuss the variation in fluorescence intensity within a molt stage among different clutches, and between molt stages.
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Molecular and mechanical characterization of minor ampullate silks from cob-web weaving spiders (Araneae: Theridiidae)
Elizabeth R Brassfield	Washington and Lee University Biology Lexington, VA USA
Cheryl Y Hayashi	University of California Riverside Biology Riverside, CA USA
Nadia A Ayoub	Washington and Lee University Biology Lexington, VA USA
Orb-weaving spiders and their relatives (Orbiculariae) make at least five different types of task-specific silks that are synthesized in unique abdominal glands. These proteinaceous fibers are all high performing materials in terms of strength and extensibility. Relating molecular sequences to mechanical properties has focused on dragline (major ampullate) silk due to its high tensile strength. However, minor ampullate silk shows a unique combination of extensibility and strength that would be desirable for a synthetically engineered material. We have thus obtained sequences of minor ampullate silk encoding genes (MiSp) from four cob-web weaving species (Theridiidae), including two complete copies (six total) from Latrodectus hesperus, L. geometricus, and L. tredecimguttatus as well as a partial sequence from Steatoda grossa. There are substantial differences in the proportions of amino acid motifs found in MiSp both between different loci in the same species and across species. For instance, one copy of L. geometricus MiSp has a high proportion of Proline-rich motifs, which likely form elastic beta-spirals, but the other copy is almost entirely composed of Alanine-rich motifs that should form beta-sheets. In contrast, L. hesperus and L. tredecimguttatus MiSp have no Proline-rich motifs and a high proportion of Alanine-rich motifs. Mechanical testing will be performed to test hypotheses that relate amino acid motifs to mechanical properties. We predict that L. geometricus minor ampullate silk, with its high Proline content, will be the most extensible, but that L. hesperus and L. tredecimguttatus silks, which are Alanine-rich, will be stronger.
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The effect of chemotactile cues from multiple predators on the condition and survival of the wolf spider Pardosa milvina (Araneae: Lycosidae)
Kelsey C Breen	Miami University Zoology Oxford, OH USA
Michael I Sitvarin	Miami University Zoology Oxford, OH USA
Ann L Rypstra	Miami University Zoology Hamilton, OH USA
Predation risk can have strong effects on the ecology and behavior of potential prey. Many arthropods detect chemical cues (excreta, feces and, for spiders, silk) from their predators. Two wolf spiders, Pardosa milvina (Araneae: Lycosidae) and Hogna helluo, and a ground-dwelling beetle, Scarites quadriceps (Coleoptera: Carabidae), coexist in agricultural fields. The spider, Pardosa, detects cues from both of the large species but responds differently to them. We studied the effect of exposure to the chemotactile cues of the larger predators as an immature on body condition and ultimately survival time of Pardosa. We placed the Pardosa in a container previously occupied by one of two predators for a period of 24 or 72 hours. Body measurements were taken before and after exposure to quantify feeding success. Spiders were then maintained in normal laboratory conditions and lifespan was recorded. Although exposure to predator chemical information had no effect on feeding success of Pardosa, there were sex differences in lifespan contingent on predator and length of exposure. Both sexes survived less time if they were exposed for 72 hrs as compared to 24 hrs. Interestingly, females that were exposed to Scarites chemical information lived longer than unexposed controls and those that were exposed to Hogna died more quickly. Males survived less time after exposure to cues from either predator than when exposed to blank substrate. The results reveal interesting indirect effects of predators on their prey and these effects likely impact the fitness of Pardosa in the field.
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How spiders avoid sticking to their own webs: clever leg movements, branched drip-tip setae, and anti-adhesives
Daniel Briceo
William G Eberhard	Smithsonian Univ Costa Rica Biologia San Jose, Costa Rica
Orb-weaving spiders construct webs with adhesive silk, but are not trapped by it. Previous studies have attributed this immunity to an oily coating on their legs that protects against adhesion or, more recently, to behavioral avoidance of sticky lines. But behavioral avoidance is not an explanation, because an orb-weaver pushes with its hind legs against sticky lines hundreds or thousands of times during the construction of a single orb and is not trapped. Video analyses of behavior and experimental observations of isolated legs contacting and pulling away from sticky lines showed that the spider reduces adhesion with an anti-adhesion chemical coating, a dense array of branched setae on the legs that reduce the area of contact with adhesive material, and careful engagement and withdrawal movements of its legs that minimize contact area with the adhesive, and avoid pulling against the line itself.
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Investigating the genetic basis of the color polymorphism in Theridion californicum
Franziska S Brunner	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
Christopher J Winchell
Grace L Anderson	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
Andrew Yee
Peter J Croucher	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
Rosemary G Gillespie	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
The leaf-dwelling spider Theridion californicum displays a remarkable polymorphism in abdominal color pattern, exhibiting more than 12 color morphs. The evolutionary history and ecological significance of this polymorphism is a topic of ongoing research. A recent population genetic study using AFLPs has demonstrated that, similar to T. californium's congener the Hawaiian Happy Face spider T. grallator, the polymorphism is maintained by frequency-dependent (balancing) selection. A next important step in the investigation of the evolutionary basis of this polymorphism is the identification of genes involved in color expression and patterning. Ommochrome pigment genes, such as vermilion and cinnabar, belong to a widely conserved pathway that has previously been demonstrated to contribute to color patterning in many arthropods including Heliconius butterflies, Drosophila melanogaster and Tribolium castaneum. We show that several ommochrome genes are expressed in the abdominal epidermis of T. californicum, making them likely candidates for the genetic basis underlying the color polymorphism. By performing in situ hybridization experiments on the abdominal epidermis, we are comparing spatial expression patterns of the aforementioned ommochrome pathway genes to the different color morphs to investigate the individual significance of those genes in T.californicum for color pattern development. Differentially expressed genes could be suitable candidates for further population genetic and phylogenetic investigations into the molecular basis and role of natural selection in shaping the independent evolution of remarkably similar color polymorphisms in multiple representatives across the family Theridiidae.
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Phylogeny-based comparative analyses of sex-specific reproductive characters in the North American leiobunine harvestmen (Opiliones: Sclerosomatidae)
Mercedes Burns	University of Maryland Entomology College Park, MD USA
Jeffrey W Shultz	University of Maryland Entomology College Park, MD USA
Marshal Hedin	San Diego State University Biology San Diego, CA USA
Sexual conflict is frequently put forth as an alternative to female choice in explaining genitalic diversity, but such proposals rarely include the historical information necessary to identify sexual arms races. We hypothesize that sexual arms races in the eastern North American leiobunine harvestmen are initiated when males alter their mating strategy from one dominated by enticement (nuptial-gift-bearing sacculate penes) to one dominated by coercion (non-sacculate penes); females then respond by evolving a defensive pre-genital barricade. Here we use parsimony and likelihood-based methods to assess whether the probability of the co-occurrence of the lanceolate penis and female barricade is significantly greater than chance and whether evolution of lanceolate penes before female barricades is more likely than alternatives. Our results show that the lanceolate male penis type is tightly correlated to the presence of a female pregenital barrier. However, because the relevant state changes always occur along the same branches and are currently represented by discrete characters, these methods cannot determine the order in which these two traits evolved. We conclude by discussing our results in terms of their implications for phylogeny-based comparative analysis of sexual arms races.
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A new trapdoor spider species from the southern Coast Ranges of California (Mygalomorphae, Antrodiaetidae, Aliatypus coylei, nov sp), including consideration of mitochondrial phylogeographic structuring.
David E Carlson	San Diego State University Biology San Diego, CA USA
Marshal Hedin	San Diego State University Biology San Diego, CA USA
The trapdoor spider genus Aliatypus (Araneae, Mygalomorphae, Antrodiaetidae) includes eleven described species, ten of which are endemic to California. Aliatypus species are known from most physiographic provinces in California, with the noticeable absence of described species from the southern Coast Ranges. Here we describe a new species (Aliatypus coylei, novsp) that is shown to occur at more than 20 locations, the majority of which are in the southern Coast Ranges. This species is morphologically most similar to members of the A. erebus species group (A. erebus Coyle and A. torridus Coyle), but differs from these latter species in several male features. Female specimens are more difficult to distinguish from A. erebus and A. torridus, but can be easily separated using DNA characters. Collection of mitochondrial DNA sequence data from 21 sites shows that A. coylei is genetically very divergent from all described Aliatypus species, and also reveals extreme population subdivision across the fragmented southern Coast Range landscape.
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A potential morphological indicator of sperm competition in spiders
Tina Chaalan
Charles Ford	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Anne Danielson-Francois	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Sperm competition has been studied in a small fraction of spider species. One potential indicator of mating systems and sperm competition would be to compare the relative sizes of the male pedipalp sperm reservoir and the female sperm storage organs (spermathecae) within a species. For example, if the comparison resulted in a 1:1 ratio, one might expect a monogamous mating system. If the ratio of male to female sperm storage amount was 1:3, one would expect polyandry and a higher amount of sperm competition. Given that the mating systems of many species of spiders are unknown, this morphological indicator might provide hypotheses to test concerning species' behavior. In our experiment, we collected orb-weaving species concentrating mainly on the spider families Araneidae and Tetragnathidae with some outgroup entelegyne and haplogyne species for comparison. We measured body and leg length as well as the size of the male pedipalp sperm reservoir and the female spermathecae. To examine male pedipalps, we first expanded the pedipalp and then measured the width, height, and length of the sperm reservoir in millimeters. To examine female spermathecae, we dissected the spermathecae and cleared them with 10% KOH making the spermatheca bulb and duct more visible before measurement. Spider species with known mating systems and levels of sperm competition were used to determine the effectiveness of the morphological comparisons.
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Evidence for the role of experience and social density on eavesdropping and social facilitation of courtship in male Schizocosa ocreata wolf spiders (Lycosidae)
David L Clark	Alma College Biology Alma, MI
Andrew Roberts	The Ohio State University Evolution Ecology and Organismal Biology Newark, OH USA
Corrina Kizer
Shira Gordan
George W Uetz	University of Cincinnati Biological Sciences Cincinnati, OH USA
Male spiders might reduce costs of finding females by “eavesdropping” and initiating sexual displays whenever male courtship is detected (i.e., social facilitation). A previous study found no evidence for eavesdropping in Schizocosa ocreata (Hentz), but involved spiders that matured in lab isolation (without exposure to behavior of adult conspecifics). In this study, males collected from the field as adults demonstrated behavior consistent with eavesdropping, i.e. increased interactive and courtship behaviors during and after video playback of a courting male stimulus. In contrast to previous findings, field-collected males showed a significantly longer duration of interactive behaviors and significantly more bouts of courtship activity when the video male stimulus was present on the video screen. Courtship rates of focal males were positively correlated with rates of courtship in video stimuli. Choice tests with two video screens showed that males recognize differences in male behavior, and respond to video stimuli of courting male wolf spiders more often and for a longer time than walking males or an empty leaf litter background (no spider). Additional studies with both live males and video playback showed that males exhibited significantly more time in courtship displays when presented with 2-3 additional males or male video stimuli simultaneously. Male responses to vibration signals from other males also varied with the presence/absence of female silk. Together, these findings suggest that experience arising from field exposure to adult conspecifics, along with additional variables such as competitor density and female chemical cues may impact male eavesdropping behavior and social facilitation.
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Paternity patterns in the giant wood spider Nephila pilipes (Araneae: Nephilidae)
Nina Cole	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
ChuehEmma Hou	Tunghai University Life Science Taichung, Taiwan
I-Min Tso	Tunghai University Life Science Taichung, Taiwan
Anne Danielson-Francois	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Sperm competition occurs when females male with multiple males and rival sperm compete to fertilize ova. In spiders, the outcome of sperm competition is thought to be influenced by female reproductive anatomy, such that haplogyne species favor the last male to mate and entelegyne species favor the first male to mate. We studied the entelegyne spider Nephila pilipes (Fabricius) in the field and the laboratory to determine its mating behavior and paternity pattern. Due to the reproductive structure of the female, we expected that the first male to mate would have the highest paternity. Approximately one hundred female and two hundred male Nephila pilipes were collected in secondary forests in Taiwan. Controlled matings took place at Tunghai University, Taiwan where females were randomly mated to two males, one of which was irradiated using the sterile-male technique. Mated females were transported to the University of Michigan and were cared for until eggs were laid. Our findings indicate that the first male to mate will not sire the most offspring as predicted, instead the amount of sperm transferred is a better predictor of paternity patterns in this species.
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Transcriptomics of exuberantly color polymorphic Theridion species (Araneae: Theridiidae).
Peter J Croucher	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
Geoff S Oxford
Rosemary G Gillespie	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
Parallel evolution of complex traits provides some of the most remarkable examples of evolution through natural selection. Among spiders, an interesting example of this phenomenon is provided by the demonstration among disparately related members of the Theridiidae of complex color polymorphisms consisting of multiple combinations of yellow, red and black dorso-abdominal pigmentation that are considered to consist of ommochromes In all studied species evidence suggests that the polymorphism is maintained by balancing selection. Given the similarity among phenotypes, and the presumed role of selection, the question is: How and to what extent is the similarity due to independent evolution on non-homologous pathways, versus differential expression of homologous pathways. In order understand the molecular basis of this parallel evolution of color polymorphism and generate a battery of spider genomic resources, we have used Illumina next-generation sequencing technology to reconstruct the transcriptomes of the two highly polymorphic spiders T. californicum and T. grallator and the genome of T. grallator. Here we focus on the assembly and annotation of tens of thousands of T. californicum gene transcripts and the identification of expressed color-pigment metabolic pathways. Results to date have given intriguing insights into numerous homologies across the genome, as well as allowing characterization of a surprisingly rich endo-symbiotic/parasitic community including nematodes and bacteria. Most importantly, we have identified key enzymes in a variety of pigment pathways, including ommochrome, pteridine, papiliochrome, heme and possibly melanin; suggesting that the potential array of pigments available to these spiders may be far greater than previously believed.
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Population genomics in a changing landscape: Area effects and natural selection in the exuberantly polymorphic spider Theridion californicum (Araneae: Theridiidae).
Peter J Croucher	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
Geoff S Oxford
Athena Lam
Rosemary G Gillespie	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
The spider Theridion californicum exhibits a dramatic dorso-abdominal color polymorphism comprising at least 12 color morphs. Using nuclear (AFLP) and mitochondrial genetic markers (CO1) we explore the population genetic structure of this species in the San Francisco Bay area. Focusing on Charles Lee Tilden Park, an area, like many in the region, that has experienced a return to a ‘natural’ (forested) landscape following centuries of human management (rangeland), we demonstrate a lack of isolation-by-distance in this species, instead revealing a pattern of ‘area effects’ indicating recent expansion of populations from scattered refugial pockets of native vegetation. Comparisons among AFLP markers and the color locus indicate that many AFLP loci, together with the color polymorphism itself, are likely to be maintained by balancing selection. As would be predicted, these markers show little of the population genetic structuring revealed by the neutral AFLP and mtDNA loci.
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Setal and sensory structures on the pedipalps of Solifugae
Paula E Cushing	Denver Museum of Nature and Science Zoology Denver, CO USA
Patrick E Casto	Denver Museum of Nature and Science Zoology Denver, CO USA
Tharina L Bird
Lorenzo Prendini	American Museum of Natural History Division of Invertebrate Zoology New York, NY USA
Solifuges, or camel spiders (order Solifugae) keep their pedipalps extended when moving through the environment and males use them during copulation. The pedipalps are covered with sensory setae and it is assumed that they are used for chemo- and mechanoreception. However, little work has been done to test this hypothesis. We used scanning electron microscopy (SEM) to examine the surface morphology of the pedipalps of solifuges representing the 12 families. Although similar sensory setae are found throughout the order, several unique setae are found only in particular families, suggesting that the patterns and structures of these setae may be phylogenetically informative.
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Solifugae: exploring the systematics and biology of a little known order of arachnids
Paula E Cushing	Denver Museum of Nature and Science Zoology Denver, CO USA
Tharina L Bird
Robert Wharton	Texas AM University Entomology College Station, TX
Jack O Brookhart
Warren Savary
Lorenzo Prendini	American Museum of Natural History Division of Invertebrate Zoology New York, NY USA
Solifugae, the sixth most diverse order of arachnids, are dominant predators in arid ecosystems on most major terrestrial landmasses. Despite their diversity, worldwide distribution, ecological importance, and fascinating morphology, behavior and life history, research on these arachnids has advanced little in 50 years. Many aspects of solifuge biology remain unknown, their taxonomy is in disarray, and an average of only five publications on the order appears annually. In 2007, Paula Cushing (Denver Museum of Nature & Science) and Lorenzo Prendini (American Museum of Natural History) were awarded a 5-year Biodiversity Surveys and Inventories grant from the U.S. National Science Foundation to study Solifugae. The objectives of this grant were to: 1) conduct a phylogenetic analysis and revise the suprageneric classification of the order based on morphological and DNA sequence data; 2) conduct several family-level taxonomic revisions within the order, also based on morphology and DNA; 3) survey, discover and describe species in the regions of highest solifuge diversity; 4) create a collaborative network of solifuge specialists; 5) train new specialists; and 6) develop a website with an online specimen database, bibliography and information about Solifugae and solifuge researchers. During this presentation we will provide a report on the project including: a preliminary molecular phylogeny of the order supporting the monophyly of many currently recognized families; a discussion of morphological character systems identified as phylogenetically informative for Solifugae; an update on revisions of the North American Eremobatidae and the African Solpugidae; a summary of results from projects exploring the diversity, internal and external morphology, biology, and behavior of solifuges; and an overview of the web-resources developed at www.solpugid.com.
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Genes expressed in venom glands of Loxosceles rufescens
Miles M Dale	Lewis & Clark College Biology Portland, OR USA
Greta J Binford	Lewis Clark College Biology Portland, OR USA
Pamela A Zobel-Thropp
Spider venoms are diverse chemical concoctions that evolved for the capture and digestion of prey. Venoms of sicariid spiders cause dermonecrotic lesions in humans, but outside of the dermonecrotic toxin sphingomyelinase D, little is known about the chemical components in their venoms. We have conducted a study to characterize the “Venome” (full set of venom components) of the sicariid spider Loxosceles rufescens. L. rufescens venom composition is of interest because they are cosmopoliton and thus have potential to be a wide ranging risk and they are members of the divergent and poorly studied North West African clade of Loxosceles. To characterize the venome we used transcriptomic (cDNA) and proteomic (MuDPIT) approaches. We identified genes with homology to SicTox gene family toxins (sphingomyelinase D), Sicaritoxins, Ctenitoxins, Lycotoxins, Theraphotoxins, Latroinsectoxins, Astacins, and various housekeeping transcripts. We isolated L. rufescens transcripts with homology to nearly all of the toxins found in other sicariid venoms. We were able to identify various evolutionary mechanisms acting on sicariid venom toxins, such as gene recruitment and duplication events. From these data we are able to better predict whether the venom gene families are conserved across the entire sicariid family.
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Genetic diversification without obvious genitalic morphological divergence in harvestmen (Opiliones, Laniatores, Sclerobunus robustus) from montane sky islands of western North America
Shahan Derkarabetian	Portland State University Biology Portland, OR USA
Joel Ledford	California Academy of Sciences Entomology San Francisco, CA
Marshal Hedin	San Diego State University Biology San Diego, CA USA
The harvestmen Sclerobunus robustus is a cryophilic species, composed of two subspecies, restricted to the montane forests distributed discontinuously across southwestern North America. Given the topological complexity and extensive geologic activity of this area, regional taxa are expected to show some degree of morphological and genetic divergence, especially if found on the southern montane ‘sky islands’. Here we examine the phylogeographic history and diversification of Sclerobunus robustus using a combination of genetic and morphological data. The most widespread subspecies, S. robustus robustus, is recovered as six genetically distinct, geographically cohesive mitochondrial phylogroups. Gene tree data for a single nuclear gene reveals congruent, albeit slightly more conservative, patterns of genetic divergence. Divergence time estimates indicate that much of the diversification within and between major phylogroups predate the Pleistocene glacial cycles. Despite high levels of genetic divergence throughout their distribution, phylogroups show extreme conservation in somatic morphology and electron microscopy reveals no differentiation in male reproductive morphology. This uncoupling of morphological and genetic differentiation may be caused by morphological conservatism associated with a conserved microhabitat preference. Based on these data, it is obvious that S. robustus has undergone some level of cryptic diversification.
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Developing an optimal Rapid Assessment Protocol for ground-accessible macro-invertebrates.
Michael L Draney	University of WisconsinGreen Bay Department of Natural Applied Sciences Green Bay, Wisconsin
Development of a Rapid Assessment Protocol (RAP) is an exercise in optimizing two antagonistic goals: Efficiency and statistical rigor. RAP’s in wide use by arachnologists today are highly efficient means of accumulating species records at a site, but comparison of data between sites or over time is problematic for at least three reasons. First, lack of randomized replication, which allows statistical comparisons of response variables across sites or over time. Second, lack of a standard sampling effort and standardized area sampled, both of which may have a large effect on total assemblage richness. Third, lack of a standard plot size sufficient to integrate microhabitat variation but small enough to ensure intensive sample effort. I have been developing an RAP that incorporates these critical experimental design features while sacrificing as little efficiency as possible. The protocol is designed so that two or more collectors, including inexperienced collectors, can take a standardized set of samples for one site in one reasonable work day. The ground-accessible fauna of any trail-accessible, walkable site of at least 50 x 50 m (0.25 ha) is sampled by intensive collection of at least three circular 0.01 ha plots randomly located on an easily surveyed grid plan. Each plot is sampled by two time-constrained methods: one hour of vegetation sampling and two hours of rapid field sieving of leaf litter. This RAP was specifically developed to enable one-day comparative sampling of tropical forest sites, but is also being tested in a variety of temperate habitat types.
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Nuptial thief: male spiders steal food from mating partners
Yevhen Drobot	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Anne Danielson-Francois	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Adult male spiders do not build webs. Once males molt to maturity, they wander in search of females to mate. For orb-weaving spiders, not building a web means that no prey can be captured and hence males cannot feed themselves. In some sexually dimorphic orb-weaving species with extremely tiny males, such as Nephila, the males are kleptoparasitic and subsist on the leftover remains of prey not eaten by females. No spider species has been observed to have males that steal prey items caught by females. Here, we report for the first time that males of at least one orb-weaving species, Tetragnatha elongata, are able to feed as adults by actively stealing food from their female partners after mating. We collected adult T. elongata in southeastern Michigan and performed 165 staged matings in the laboratory. We found that male food-stealing behavior was significantly influenced by the relative body masses of males and females. When the difference in body mass was minimal, males were able to steal prey. This finding suggests that males may have a trade-off between acquiring food resources and achieving greater reproductive success with larger more fecund females.
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Demographic influences on dispersal in the newly dominant cellar spider, Pholcus manueli (Pholcidae)
Jonathan D Edwards	Miami University Zoology Oxford, OH USA
Ann L Rypstra	Miami University Zoology Hamilton, OH USA
The cellar spider, Pholcus manueli (Araneae, Pholcidae), has recently expanded its range in North America and is now abundant and successful throughout the Midwest. However, little is known about its biology and especially factors that might influence its dispersal. In laboratory and field manipulations, we explored the effects of sex ratio and density on dispersal of both males and females. In a laboratory experiment we manipulated the perceived sex ratio by placing six uninhabited recently constructed webs in the center of a large terrarium. Webs in each treatment were constructed either by all females or all males. A spider was placed in the center and allowed 24 hrs to either stay in the center of the arena (remain) or occupy the peripheral area (disperse). Using a logistic regression to analyze these data, both males and females reacted in a similar way to the webs based on the sex of the web builders with a significant avoidance of the male webs (p=0.005). In a field study, we established populations with two densities and with contrasting in enclosures and then removed the enclosure and monitored their dispersal. After running a proportional hazards analysis on these data neither sex ratios nor density had an effect on the proportion of each sex dispersing. However, by using a log linear analysis, the sex bias of the treatment did affect dispersal frequency of each sex. Therefore, movement of these spiders between patches is caused, at least in part, by the demography of the population, which may help explain why these animals are expanding their range into areas recently held by a congeneric, Pholcus phalangioides (Araneae, Pholcidae).
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The first North American records of the synanthropic spider Cithaeron praedonius O. P.-Cambridge (Araneae: Gnaphosoidea: Cithaeronidae), with notes on its biology
G B Edwards	Florida State Collection of Arthropods Division of Plant Industry Gainesville, Florida, USA
Joe T Stiles	Saint Leo University Information Technologies Saint Leo, Florida, USA
Cithaeron praedonius O. P.-Cambridge 1872 is an Old World species with a distribution from Libya and Greece to Malaysia and Australia. In the New World, it was recently found in Brazil, and is now reported for the first time in North America, in the United States, State of Florida. Multiple individuals of both sexes and various life stages, including multiple eggsacs, have been found in a home in Port Richey, Pasco County. An adult female was found on the outside wall of the house feeding on another spider, suggesting that C. praedonius are no longer contained as a spot introduction in this one house. Observations in captivity indicate that this species may prefer feeding on other spiders. The eggsac and molting nest are described for the first time, and records on fecundity reported.
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Adaptive foraging in orb-weaving spiders: predicting adaptive changes in web structure in response to change in hunger level using a computer simulation model.
Samuel C Evans	University of Akron Biology Akron, OH USA
Todd A Blackledge	University of Akron Biology Akron, OH USA
Orb-weaving spiders rebuild their webs daily using a finite volume of silk, which scales positively with spider body mass, as does the energy absorption potential of the silk threads. The “large, rare prey hypothesis” dictates that spiders build webs that maximize the probability of securing large-but-rarely-encountered prey, which are essential to the spider’s reproductive success. However, this likely involves concentrating the allotment of silk in a web of smaller planar area, which lowers the prey-web encounter rate. Therefore, there is an apparent trade-off between prey-web encounter rate and web performance. Spiders that have not recently secured a sizeable meal, and are therefore close to starving, might benefit from a “bet-hedging” strategy of increasing web size to increase prey-web encounter rate, while spiders that are further away from starvation benefit more from gambling with a smaller web that is more effective at securing a large prey item. Therefore, we hypothesize that spiders can adaptively alter web size in response to change in proximity to starvation (“hunger level”). To generate predictions based on this hypothesis, we have constructed a computer simulation model. Prey capture is a three-step process: the web must 1) contact, 2) stop, and 3) retain the prey item. Our model calculates a probability of success in each of these three steps; the product of these probabilities is the probability of prey capture. This process is repeated over thirty days, or until the spider starves, and the growth rates and survival frequencies are compared among spiders using different strategies. Model predictions and planned empirical tests will be discussed.
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Arachnid Recovery of Mount St. Helens
Katherine M Fiedler	Lewis & Clark College Biology Portland, OR USA
Greta J Binford	Lewis Clark College Biology Portland, OR USA
Charlie M Crisafulli
The 1980 eruption of Mount St. Helens has served as a living ecological laboratory to examine the recovery of different communities and entire ecosystems. A comparison of arachnid species diversity and community composition over time (1990, 2000, and 2010) and across a scale of disturbance sites (reference forest, tephra forest, blowdown forest, and pumice plain) shows different trajectories of recovery. These comparisons can be made through species identification of individuals collected in pitfall trap samples, as well as feeding guild and habitat distinctions. Disturbed sites have provided ecological niches unavailable in the pre-eruption old growth forests. Furthermore, non-native desert species (e.g. Xysticus cunctator) and invasives (e.g. Phalangium opilio) have been able to take advantage of early successional landscapes. This examination of arachnid recovery can contribute to an understanding of the overall recovery of these ecosystems.
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Sex amongst cannibals: the reproductive behavior of a mimetid spider.
Charles Ford	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Anne Danielson-Francois	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Spiders of the family Mimetidae, commonly known as the pirate spiders, are some of the most intriguing and lesser-known araneophagic spiders. Despite their reasonably high population density, only a few researchers have studied their predatory behavior and the reproductive behavior of pirate spiders is unknown. How these spider-eating cannibals mate has been an intriguing theoretical question until now. This study is the first description of reproductive behavior of any pirate spider species. We describe the mating behavior of a fairly common species found in southeastern Michigan and surrounding areas.
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Scorpion fluorescence and reaction to light
Douglas D Gaffin	University of Oklahoma Department of Zoology Norman, Oklahoma USA
Lloyd A Bumm	University of Oklahoma Homer L Dodge Department of Physics and Astronomy Norman, Oklahoma USA
Nataliya V Popokina	University of Oklahoma Department of Zoology Norman, Oklahoma USA
Matthew S Taylor	University of Oklahoma Department of Zoology Norman, Oklahoma USA
Shivani Mann	University of Oklahoma Department of Zoology Norman, Oklahoma USA
Scorpion fluorescence is a mystery. These largely solitary, nocturnal arachnids glow a bright cyan-green under UV light. Interestingly, previous studies of four species from three families have shown that scorpion lateral and medial eyes are maximally sensitive to green light (around 500 nm) and secondarily to UV (350 to 400 nm). We used light-avoidance behavior to assay the responses of desert grassland scorpions, Paruroctonus utahensis, to 395 nm UV light, 505 nm cyan-green light, 565 nm green light, and no light within small, circular arenas. Based on the eye sensitivity data, we predicted maximal response to 505 nm, followed by lower responses to 395 and 565 nm. In our experiments, however, scorpions responded most intensely to 395 nm and 505 nm. In field observations, we often spot P. utahensis beneath isolated twigs amid open sand. Other studies indicate that photosensitive elements in scorpion tails are sensitive to green light. We therefore propose that the cuticle may function as a whole-body photon collector, transducing UV light to cyan-green before relaying this information to the CNS. The animal may use this information to detect shelter, as blocking any part of the cuticle could diminish the signal. We are conducting behavioral trials on scorpions with their eyes blocked or fluorescence diminished by sunscreen. We predict that scorpions with eyes blocked will respond to UV but display diminished response to green, whereas sunscreen-treated scorpions will show the opposite result. If confirmed, these results would suggest an active role for fluorescence in scorpion light detection.
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Sperm release patterns in two species of funnel-weaving spiders (Agelenidae)
Sabah Gagnon	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Samaa Lutfi	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Anne Danielson-Francois	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Sperm competition can occur when females mate with more than one male. Males that transfer more sperm than their rivals are more likely to father more offspring when sperm competition is present. We studied the sperm release patterns of two species of funnel-weaving spiders, Agelenopsis pennsylvanica and Agelenopsis longistyla (Agelenidae). Penultimates were collected and reared in the laboratory. To observe sperm transfer, staged matings between virgins were conducted in the laboratory. Males were frozen immediately after mating. The amount of sperm remaining in pedipalps and the amount transferred to the female were measured. We found the two species had different patterns of sperm transfer. In general larger males had more sperm than smaller males, suggesting that larger males have an advantage in sperm competition.
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A preliminary investigation of the black widow spider venom transcriptome using next-generation sequencing.
Jessica E Garb	University of Massachusetts Lowell Biological Sciences Lowell, MA
Nadia A Ayoub	Washington and Lee University Biology Lexington, VA USA
Alexander K Lancaster	Whitehead Institute for Biomedical Research Cambridge, MA USA
Cheryl Y Hayashi	University of California Riverside Biology Riverside, CA USA
Animal venoms play a central role in deciphering vertebrate physiology and are essential resources for the development of novel pharmaceuticals and lifesaving antivenoms. Venoms also have significance for understanding biochemical variability as they exhibit many textbook cases of molecular evolution, including unusually high mutation rates, radiation of multi-gene families, molecular convergence, lateral gene transfer and gene-level co-evolutionary arms races. Despite the tremendous biological importance of animal venoms, knowledge of their molecular composition is surprisingly limited in relation to the variety of venoms in nature. We are using next-generation sequencing technology to examine the composition, diversity and evolution of black widow spider venom. To catalog venom gland expressed genes, we have generated an Illumina RNA-seq library from venom glands of the Western black widow spider (Latrodectus hesperus), resulting in many thousands of novel sequences. The Illumina sequence assembly will be compared to sequences from traditional venom cDNA libraries, in addition to Illumina RNA-seq libraries from other L. hesperus tissues to investigate venom transcriptome complexity, as well as to identify genes exhibiting venom-specific patterns of expression. Our preliminary results will be expanded across related species to identify key changes in venom composition associated with the evolution of the highly potent black widow spider venom.
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Morphological and molecular homology and repurposing of the spider silk spinning apparatus.
Jessica E Garb	University of Massachusetts Lowell Biological Sciences Lowell, MA
Cheryl Y Hayashi	University of California Riverside Biology Riverside, CA USA
Spiders are unparalleled in the diversity of functionally distinct silks they spin, including silks for egg-case construction, different web elements, and adhesion. The production of silk has been best characterized in araneoid (orb-weaving) spiders, a derived lineage typically possessing seven categories of morphologically distinctive silk glands, each expressing unique silk proteins that compose silk fibers. The majority of these proteins belong to the spidroin (spider fibroin) gene family. The phylogenetic distribution of these seven gland types and their functional roles is poorly known outside of araneoids, because silk glands exhibit great diversity in their morphology and numbers across spider families. In this study, we conducted a comparative analysis of the spinning organs and spidroin proteins involved in egg-case silk production in distantly related spiders. Specifically, we identified glands in the haplogyne spider Diguetia canities involved in egg-case silk synthesis, based on amino acid composition of their silk glands and egg-case silk fibers. We also identified the primary spidroin composing D. canities egg-case fibers from silk gland cDNA libraries. D. canities synthesizes egg-case silk from glands that are morphologically dissimilar to araneoid tubuliform (egg-case) silk glands. Moreover, the egg-case silk of D. canities is composed of a spidroin that is extremely divergent from the araneoid tubuliform spidroin (TuSp1) in its repetitive architecture and sequence. We inferred the phylogenetic position of the D. canities egg-case spidroin relative to TuSp1 and consider the distribution of egg-case silk glands and spigots across families to examine the evolution of the machinery involved in silk production.
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UV reflectance in crab spiders (Thomisidae) is derived from guanine crystals
Felipe M Gawryszewski	Macquarie University Biological Sciences Sydney NSW, Australia
Debra Birch
Marie E Herberstein
The diversity of colours in animals reflects the variety of selection pressures that animal colouration are subjected to. Despite the remarkable number of studies on the function of animal colouration, the full understating of the adaptive significance of colouration can only be complete when the mechanism of colour production is known. Crab spiders (Thomisidae) are a diverse family of sit-and-wait predators. Some crab spiders that ambush prey on flowers are UV-reflective, creating a colour contrast against the flowers that is attractive for pollinators. These spiders are also known by their ability of changing colour, including the UV component, over a few days. Here we investigated the mechanism of colour variation in Thomisidae species, with emphasis in the UV. The analyses showed that high UV colouration is achieved by exposing UV-reflective guanine crystals, present in storage cells bellow the hypodermis, through an UV-transmitting hypodermis and cuticle. White non-UV and yellow colouration are achieved by the presence of ommochrome pigments in different stages in the hypodermic cells, filtering the UV-reflective guanine crystals. Furthermore, the cuticle of spiders are not transparent to light (300-700 nm) as previously argued and therefore it is an important component on the formation of spider colours.
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Adaptive radiation on remote islands: Comparison of diversification across the remote archipelagos of Polynesia
Rosemary G Gillespie	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
The Pacific Ocean contains more islands than the rest of the world's oceans combined. The most remote high islands are those of Polynesia, notably the Hawaiian Islands, and the three archipelagos of French Polynesia: the Society, Marquesas, and Australs. Each of these archipelagos is a hotspot, with islands arranged chronologically from the south east. While patterns of adaptive radiation are relatively well known in Hawaii, comparable patterns in the other archipelagos of Polynesia are less well known. Here I will compare patterns of diversification of spider lineages across the archipelagos to assess the similarity in species, pattern and rate of diversification, and dynamics of community assembly. The Societies show high endemism, in particular on the youngest high island of Tahiti, with the genus Tetragnatha a prominent element of the spider biota at both high and middle elevations; relationships appear to be horizontal, with cloud forest species closely related to each other. The Marquesas show high endemism, with Tetragnatha again a prominent element, the highest diversity being on the older islands. The Austral Islands are an older, smaller, and lower archipelago; here, the dominant lineages are Tangaroa tahitiensis (Uloboridae) and Misumenops rapaensis (Thomisidae). These taxa are endemic to the archipelago rather than an individual island, yet there are large genetic distances between island populations, with sequential colonization of islands. Compared to Hawaii, diversification is less pronounced, and community assembly on the youngest island matches to the second youngest island of the Hawaiian chain.
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Does spider silk hold a "memory" of the spinning process?
Cindy Gonzalez	California State University Fullerton Biological Science Fullerton, CA USA
Rosa M Ayala
Merri L Casem	California State University Fullerton Biological Science Fullerton, CA USA
Hydration of major ampullate (MA) silk leads to an increase in fiber diameter and a decrease in fiber length. This change is known as supercontraction. Previous studies have shown that supercontraction disrupts intra/intermolecular hydrogen bonding leading to a rearrangement of spidroin motifs. When MA silk from the spider, Nephila clavipes, undergoes supercontraction in 8M urea, the silk takes on a distinct banded appearance. While the pattern of banding is variable, at any point along the length of the silk the two individual MA fibers that make up the spider’s dragline are identical. We propose that some factor (or factors) are acting in concert on the fibers as they are being drawn from the individual silk glands of the spider. We have examined the influence of reeling speed on the banding pattern of supercontracted silk. MA silk was collected from N. clavipes at different reeling speeds. Silk was supercontracted using either distilled water or 8M urea. Diameters of control or water hydrated silk fibers did not change with reeling speed. In contrast, the diameter of the urea-hydrated silk did show a statistically significant change with increasing reeling speed. The pattern of banding was only found in the urea-hydrated silk samples. The complexity of the banding pattern also increased with increasing reeling speed. These results suggest that the pattern of banding found in 8M urea supercontracted MA silk may represent a ‘memory’ of the physiological forces applied to the silk fibers during the spinning process.
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Comparative phylogeography of three Great Basin scorpions: further insight into the biotic assembly of North America’s cold desert
Matthew R Graham	University of Nevada Las Vegas School of Life Sciences Las Vegas, NV USA
Jef R Jaeger	University of Nevada Las Vegas School of Life Sciences Las Vegas, NV USA
Brett R Riddle	University of Nevada Las Vegas School of Life Sciences Las Vegas, NV USA
Lorenzo Prendini	American Museum of Natural History Division of Invertebrate Zoology New York, NY USA
The biotas of the Great Basin Desert of western North America were continuously altered by Pleistocene climate cycles. Since the Last Glacial Maximum (LGM) about 21 kya, Great Basin climates have warmed considerably, resulting in expansions of arid environments and contractions of cooler shrub-steppe habitats. Distributions of terrestrial taxa within these habitats are typically thought to have shifted accordingly, but recent evidence from vertebrates (reptiles, mammals) suggests that responses to historical climate change in the Great Basin were not always congruent across co-distributed taxa. We first constructed current and Late Glacial species distribution models (SDMs) for three distantly related scorpion species (Anuroctonus phaiodactylus, Hadrurus spadix and Paruroctonus becki) to model their distributional responses to the LGM to Holocene climate transition. Model results were largely congruent, predicting northward expansion from southern areas of warmer climate following the LGM. We then tested this hypothesis by analyzing genetic and morphological data. In accordance with SDM predictions, all species depicted high genetic and morphological diversity in southern areas and lower diversity in northern areas. The patterns, however, indicated that these scorpions may have expanded their ranges from populations within the Great Basin (in the Lahontan and Bonneville basins), as well as from more southern populations as predicted by the SDMs. These preliminary results add scorpions to a growing array of vertebrate and invertebrate Great Basin species whose gene diversity demonstrates a more complex response to the LGM to Holocene climate transition than is revealed by SDMs.
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On a fascinating new haplogyne spider from Southern Oregon caves
Charles Griswold	California Academy of Sciences Entomology San Francisco, CA
Joel Ledford	California Academy of Sciences Entomology San Francisco, CA
Tracy Audisio	California Academy of Sciences Entomology San Francisco, CA
A recent survey of caves in Southern Oregon has discovered a fascinating new haplogyne spider that cannot be confidently assigned to any known family. We provide an overview of this spider’s unique morphology and discuss alternatives for its phylogenetic placement.
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Relationship between octopamine and male mating tactic expression and female experience in the wolf spider Rabidosa punctulata
Matthew D Hansen	University of Nebraska School of Biological Sciences Lincoln, NE USA
Dustin J Wilgers
Thomas C Jones	East Tennessee State University Biological Sciences Johnson City, TN
Hebets A Eileen
Octopamine (OA) is a biogenic amine that can act as a neurotransmitter, a neurohormone, and a neuromodulator. In insects, it is often referenced as the “fight or flight” hormone, and in Drosophila, octopamine has been shown to modulate aggression. In the wolf spider Rabidosa punctulata, two different male mating tactics are observed during reproductive behavior. The first, and most common, is courtship, in which the male displays a series of leg waves and stridulations (seismic signals). The second, and more aggressive tactic expressed, is a direct mount, in which the male foregoes courtship and ‘forcibly’ mounts the female. The mechanism(s) underlying the expression of the different tactics is currently unknown. Given the documented relationship between OA levels and aggression in other arthropods, we predicted that males that express a direct mount tactic have higher circulating OA levels than those that express courtship. Immediately after tactic expression in laboratory mating trials, haemolymph was collected from R. rabida males and was subsequently assayed for OA. As predicted, we found that OA level was dependent on male mating tactic expression, with higher levels of OA in males that expressed a direct mount. Additionally, we found overall differences in OA level between males and females (significantly higher in males) and differences in OA levels between naïve females and those previously paired with males.
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Chthonioid pseudoscorpions: a phylogenetic analysis based on morphology
Mark S Harvey	Western Australian Museum Terrestrial Zoology Perth, Western Australia, Australia
The pseudoscorpion superfamily Chthonioidea is well defined and seemingly monophyletic based on previously published morphological and molecular datasets using multiple markers. However, the higher classification is not settled with several alterations over the past two decades. To assist resolve these issues, a phylogenetic analysis was performed using 150 chthonioid species placed in 38 of the 48 recognised genera. Parsimony analyses under equal weights provided little phylogenetic resolution. Implied weights analyses drastically improved the resolution of the trees and, in all analyses, Pseudotyrannochthoniidae were sister to the remaining chthonioids. In both equal and implied weights analyses, the taxa currently included in the families Tridenchthoniidae and Lechytiidae grouped strongly with the chthoniid genera Sathrochthonius and Sathrochthoniella. Of the remaining taxa, low concavity functions distinguished three other clades, Chthoniini, Tyrannochthoniini and the “apochthoniines” (Apochthonius + Kleptochthonius). Higher concavity functions retained Tyrannochthoniini and the “apochthoniines”, but divided Chthoniini into multiple clades. Proposed changes to the classification of the Chthonioidea are discussed.
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Enigmatic ornamentation eases male reliance on courtship performance for mating success
Eileen A Hebets	University of Nebraska School of Biological Sciences Lincoln, NE USA
Jay A Stafstrom
Rafael L Rodriguez
Dustin J Wilgers
Female preferences are frequently invoked to explain the widespread occurrence of elaborate male ornaments, yet empirical data demonstrating such preferences are sometimes equivocal or even contradictory. In the wolf spider, Schizocosa stridulans, despite evidence of strong female choice, prior research has been unable to link the conspicuous sexually dimorphic foreleg ornamentation of males to their mating success. We conducted three experiments aimed at determining the function of this previously enigmatic ornamentation. Our first two experiments used males with phenotypically modified foreleg phenotypes in simple and complex mating environments in order to examine the relationship between the presence/absence of ornamentation and male mating success. In both experiments, we found no relationship - courtship rate was the sole predictor of mating success. In a third experiment, we used males with naturally varying foreleg ornamentation in mating trials. Ornamentation was subsequently quantified and we again examined the factors influencing male mating success. As in our first two experiments, we found courtship rate to be a good predictor of mating success. Additionally, we discovered that foreleg ornamentation and courtship rate interact to influence male mating success. At low courtship rates, males with more foreleg ornamentation have a mating advantage, while at high courtship rates males with less foreleg ornamentation have a mating advantage. We discuss several potential explanations for these results. In summary, we provide the first evidence of a benefit of foreleg ornamentation in male S. stridulans and suggest that this benefit is realized by the interaction between ornamentation and courtship rate.
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Harvestmen Transcriptomics
Marshal Hedin	San Diego State University Biology San Diego, CA USA
Axel Schoenhofer
Sajia Akhter	San Diego State University Computer Science San Diego, CA
James Starrett	University of California Riverside Biology Riverside, CA USA
Jeffrey W Shultz	University of Maryland Entomology College Park, MD USA
Next generation sequencing (NGS) technology can now be used to efficiently characterize previously unknown genomes from non-model taxa. This flood of data, in combination with new multigenic analytical methods, is transforming the field of molecular systematics. We have collected transcriptome data (NGS characterization of the transcribed portion of the genome from mRNA) for multiple Opiliones species representing three of four major harvestmen lineages. For each taxon we generated gigabase quantities of data using Illumina short-read NGS technology, and successfully conducted de novo assemblies of these data. The comparative assembled data have multiple possible uses – our initial focus centers on the development of PCR primers for multigenic phylogenetics. For relatively ancient divergences we have targeted protein-coding genes that are “single copy, single exon” genes in Ixodes (only available annotated arachnid genome). The harvestmen transcriptomes include hundreds of such genes (most nearly full-length with high coverage); we report on primer design and testing for a subset of these genes. For more recent divergences we are developing EPIC (exon-primed intron-crossing) primers, targeting genes known to have introns with conserved position in other arthropod taxa. Again, hundreds of suitable candidates are found in our comparative Opiliones transcriptomes.
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A multifaceted taxonomic assessment of the tarantula Aphonopelma anax (Araneae: Theraphosidae) and its close relatives from South Texas
Brent E Hendrixson	Millsaps College Biology Jackson, MS USA
Majel V Purvis	Millsaps College Biology Jackson, MS USA
The tarantula genus Aphonopelma comprises at least 90 species throughout the United States, Mexico, and portions of Central America. Despite this putative diversity, however, very few non-type specimens can be confidently identified using available taxonomic keys or species descriptions; consequently, species boundaries in this interesting group of spiders remain obscure and problematic. Of particular interest is the species A. anax and its close relatives A. harlingenum and A. breenei from South Texas. These spiders have been described on the basis of only a few individuals, resulting in poorly defined limits of intraspecific and interspecific variation. In order to assess species boundaries in this group, we employed a multifaceted taxonomic approach utilizing genetic and geospatial data. Our results demonstrate that these three nominal species are genetically and ecologically “cohesive" and should no longer be recognized as three distinct species; instead, our data support the synonymy of A. harlingenum and A. breenei under the name A. anax. Our results further show that A. anax-like specimens from some western localities belong to a genetically divergent lineage; however, geospatial analyses do not demonstrate concomitant ecological divergence between western and eastern populations. As such, we argue that A. anax is the only “large brown” tarantula species in South Texas, but it possesses substantial genetic diversity that appears roughly structured along the boundary between the following Level III Ecoregions: the Southern Texas Plains and the Western Gulf Coastal Plain.
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Spider Glue Silk Proteins: Molecules with Novel Biomimetic Potential
Yang Hsia	University of the Pacific Biological Sciences Stockton, CA USA
Eric H Gnesa	University of the Pacific Biological Sciences Stockton, CA USA
Craig A Vierra	University of the Pacific Biological Sciences Stockton, CA USA
Spider silks have been under natural selection for millions of years, resulting in diversity of function along with unique mechanical properties. Because it is impractical to farm and harvest spider silk for various reasons, the ability to produce synthetic fibers from recombinant spider silk proteins allows for the potential to develop a new unique class of biomimetic materials. Here we investigate the structural and mechanical properties of pyriform silks from the golden orb-weaver, Nephila clavipes. Nanoscale indentation measurements using atomic force microscopy on natural pyriform silk suggests this biomaterial has high toughness that may be suitable for dissipating high amounts of mechanical energy, possibly due to the occurrence of highly organized nanocrystals. In contrast to dragline silks, amino acid sequence analysis reveals that the glue silk protein, Pyriform Spidroin 2 (PySp2), does not contain the traditional poly-(Gly-Ala) and poly-Ala repeats that have been shown to contribute to strength and extensibility. We hypothesized that PySp2 contains new protein motifs sufficient to polymerize into functional structures. To investigate the functional contributions of these novel motifs during pyriform fiber assembly, we expressed and spun different recombinant PySp2 proteins with various portions spanning its block repeat units into fibers. In addition, we demonstrate recombinant PySp2 proteins that contain single block repeat units can self-assemble into foam-like nanostructures. Taken together, our findings suggest glue silk proteins can be used for a wide range of biomimetic materials with morphologies ranging from fibers to porous structures.
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Morphological analysis of montane scorpions (Vaejovis) in Arizona
Garrett B Hughes	University of Arizona Entomology and Insect Science Tucson, Arizona, USA
Several scorpions of the genus Vaejovis in Arizona are restricted in range to mountain top forests. These scorpions, informally referred to as the “vorhiesi complex” are very similar morphologically, but their geographic distribution has attracted the attention of several researchers, resulting in the description of a few new species in recent years. However, these species were described from small sample sizes and were diagnosed with questionable characters that were not sufficiently analyzed. This study evaluates the morphology of scorpions of the “vorhiesi complex” from seven regions in Arizona to verify the validity of the species and their accompanying diagnoses. Morphological characters examined include morphometrics, hemispermatophores, size and shape of subaculear tubercles of the telson vessicle, pectinal tooth counts, pedipalp chela denticle counts, metasomal setal counts, development of metasomal carinae, and tarsal spinule counts. New diagnoses are given for previously described species (V. vorhiesi Stahnke 1940; V. lapidicola Stahnke 1940; V. paysonensis Soleglad 1973; V. cashi Graham 2007; and V. deboerae Ayrey 2009), which are considered valid, based on the morphological evidence gathered. A new species of Vaejovis is described from the Piñaleno Mountains in Arizona.
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Evolutionary dynamics of social structure in the polyphenic spider Anelosimus studiosus (Araneae: Therdiidae)
Thomas C Jones	East Tennessee State University Biological Sciences Johnson City, TN
Nathan O Weber
Brent J Linville
In east Tennessee Anelosimus studiosus occur in both solitary and social colonies. Solitary colonies are predominant, with social colonies tending to be found in isolated clusters around the range. Previous work demonstrates that social tendency is a heritable trait, and that in cooler microclimates there is a selective advantage to females in small colonies. A remaining question is: if there is an advantage to the social phenotype, why are social colonies rare in the population. One hypothesis is that social colonies are a recently evolved phenomenon, perhaps coinciding with water impoundments over the last century. Another hypothesis is that negative frequency-dependent selection selects against the social phenotype when colonies grow too large for the environment to support. We present molecular results suggesting that local clusters of social colonies evolved independently several times, and demographic data that are consistent with frequency-dependent (boom/bust) dynamics.
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Effects of Food Limitation on Locomotory Behavior in Tarantulas (Brachypelma albopilosum)
Michael H Kaminski	Eastern Michigan University Biology Ypsilanti, MI
Cara Shillington	Eastern Michigan University Biology Ypsilanti, MI
Tarantulas are typically considered sit-and-wait predators. During periods of extreme prey scarcity however, they can either increase activity levels to find more prey or decrease activity levels and possibly metabolic rates to save energy. We examined changes in locomotory activity in tarantulas (Brachypelma albopilosum) in response to prey scarcity. Initially all tarantulas were fed 20-25% of their body mass and activity levels were recorded over a 6-hour period. Tarantulas were then separated randomly into two groups and over a three month period were fed a cricket diet of either 20-25% body mass or 3-6% body mass and activity levels of the two groups were again compared. No differences were found in activity levels in the initial trial. However, after 3-months of differential feeding between groups, tarantulas in the food-limited group had significantly more bouts of movement even though they did not necessarily travel greater distances. Our findings suggest that prey scarcity can reach low enough levels that B. albopilosum will alter its sit-and-wait foraging strategy to pursue a more active foraging strategy. A more active foraging strategy increases the likelihood that B. albopilosum will encounter potential prey items and thus may affect survival and lifetime fitness.
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Evidence for biological control of the Russian wheat aphid with spiders in winter wheat
Lauren M Kerzicnik
Eric C Chapman	University of Kentucky Department of Entomology Lexington, KY USA
James D Harwood	University of Kentucky Department of Entomology Lexington, KY USA
Frank B Peairs	Colorado State University Department of Bioagricultural Sciences and Pest Management Fort Collins, CO USA
Paula E Cushing	Denver Museum of Nature and Science Zoology Denver, CO USA
The Russian wheat aphid, Diuraphis noxia (Hemiptera: Aphididae) is a significant pest of wheat agroecosystems in the United States. Establishing appropriate predator-prey linkages is important for the conservation biological control of pests within these systems. We used gut-content analysis through PCR as a minimally disruptive technique to describe the connection between two spider species, Tetragnatha laboriosa and Pardosa sternalis, and D. noxia. A partial 1146 bp sequence from the mitochondrial cytochrome oxidase I (COI) gene was used to amplify a species-specific 227 bp fragment of D. noxia DNA. We tested the hypotheses that both T. laboriosa and P. sternalis densities and predation on D. noxia would be highest at the highest aphid infestation level in the aphid-resistant wheat cultivar plots. Over 92% of T. laboriosa were collected at the 1x or 10x D. noxia infestation levels combined, demonstrating that T. laboriosa was tracking D. noxia densities. Additionally, P. sternalis predation on D. noxia increased with increasing aphid infestation levels. Feeding trials indicated that T. laboriosa and P. sternalis molecular half-lives for D. noxia DNA were 4.0 h and 2.0 h, respectively. 32% and 48% of field-collected T. laboriosa and P. sternalis spiders screened positive for the presence of D. noxia DNA, respectively. These results suggest that both T. laboriosa and P. sternalis are essential natural enemies for reducing D. noxia densities.
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Microstructure of the Dragline Spinning Duct in the Spider Nephila clavata (Araneae: Nephilidae)
Hoon Kim	Dankook University Biological Sciences Cheonan, Korea
Jong-gu Park	Dankook University Biological Sciences Cheonan, Korea
Myung-jin Moon	Dankook University Biological Sciences Cheonan, Korea
Silk spinning by araneid spiders are the most complicated and differentiated thread-producing procedures in animals. Recently, spider's dragline silks has been a major goal of biomimetic research for mass-production of artificial silks because of their outstanding tensile strength and toughness. Morphologically, the duct of ampullate gland for producing the dragline silk loops back on itself to form an S-shape and thereby is divided into three limbs of duct sections. As the feedstock passes through the long duct of the large ampullate glands, the polymerized dragline silk fibers are finally produced at the end of its spinning nozzle. Although the importance of this extra length is still not fully understood, our microstructural observations suggest that each limb of the duct may have distinctive functions in the dragline production because each limb seems to be containing different phases of silk, and its cuticular layers or cell types are combined with radical decrease of diameter. Thus, we demonstrate here some microstructural properties of the dragline processing system of the major ampullate gland in Nephila clavata using various visualizations including light and electron microscopy.
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The effect of habitat manipulation on spider distribution and predation of viruliferous aphids
Katelyn A Kowles	University of Kentucky Department of Entomology Lexington, KY USA
Douglas W Johnson
James D Harwood	University of Kentucky Department of Entomology Lexington, KY USA
Aphids are pests of multiple cropping systems, due to the viruses they vector and the staggering populations they can build within a single season. In Kentucky winter wheat, grain aphids (Rhopalosiphum padi, Sitobion avenae) cause substantial yield loss as vectors of Barley Yellow Dwarf virus (BYDV), prompting multiple insecticide applications. They transfer the virus from infected to healthy plants as they feed, causing discoloration, stunted growth and sterility. Importantly, these aphids are preyed upon by foliage dwelling predators and, when they fall to the ground, epigeal spiders which play a major role in preventing re-colonization of the plant. This project examines the effect of habitat manipulations, specifically weed strips, on spider distribution and predation in winter wheat fields. Four fields, approximately one acre each, were divided into two treatments: one with two weed strips on opposing sides, and one with no weed strips. Aphids, spiders, generalist predators and plants were sampled over the course of the season, and enzyme linked immunosorbent assay (ELISA) was used to test for BYDV throughout this food web. Additionally, spatial analysis was undertaken to observe the distribution of the spiders in the fields and also relative to the weed strips. The results are discussed in the context of conservation biological control, as this project aims to use spiders and other generalist predators as more sustainable management approaches for pest control.
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Fossil spiders from the Lower Cretaceous Crato Lagerstätte, Brazil
James C Lamsdell	University of Kansas Department of Geology Lawrence, KS USA
Paul A Selden	University of Kansas Paleontological Institute Lawrence, KS USA
At present three spider species have been described from the Crato Formation of Brazil, a single araneomorph (Cretaraneus matinsnetoi) and two mygalomorphs (Cretadiplura ceara and Dinoplura ambulacra), known from a total of five published specimens. Preliminary study of almost a hundred un-described Crato spider specimens reveals two more mygalomorphs, and at least three araneomorph species. The mygalomorphs are probably assignable to Cretadiplura ceara and display details of the coxosternal region that are not observable in the type specimens. The most common araneomorph is probably congeneric (if not conspecific) with Cretaraneus martinsnetoi, however neither this nor the original material displays the characteristics of Cretaraneus and its assignment needs revision. Two large specimens resemble nephilids, while a single small specimen may represent a palpimanid. Further work is required to accurately identify these specimens. Many of the Crato spiders are preserved in an uncompressed, three-dimensional state, and it is hoped that CT-scanning may reveal further details of their morphology preserved within the matrix that will assist in their identification.
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Building the silk gland transcriptome for the Western black widow (Araneae, Theridiidae, Latrodectus hesperus)
Amanda K Lane	Washington and Lee University Biology Lexington, VA USA
Patrick A Oley	Washington and Lee University Biology Lexington, VA USA
Nadia A Ayoub	Washington and Lee University Biology Lexington, VA USA
Orb-weaving spiders and their relatives synthesize up to seven functionally distinct high-performance silk fibers in specialized abdominal glands. These fibers are primarily composed of structural proteins termed spidroins (spider fibroins). Some of the genes encoding spidroins have been described for a select number of spider species, and virtually all molecular models of silk properties rely on the sequences of spidroins alone. However, non-spidroin genes must also play important roles in silk synthesis. We are using high-throughput sequencing to describe the entire suite of genes expressed in the silk glands of three cob-web weaving spider species (Theridiidae). We constructed a preliminary database of genes expressed in the silk glands of the Western black widow, Latrodectus hesperus, using de novo assembly of 34 million 75 base pair sequences. This initially resulted in 18,000 contiguous sequences (contigs) greater than 200 base pairs long. Here, we focused on improving the quality and contiguity of a subset of 175 contigs, which based on homology searches were predicted to represent only 27 unique genes. We reduced the number of contigs to 143 and added over 7000 base pairs of sequence data. This resulted in at least 22 complete, high quality black widow genes. We additionally identified 70 non-identical contigs that nevertheless displayed homology to each other and thus likely represent paralogous gene copies. These genes were specifically chosen for their high rate of expression in silk glands and thus offer important insights into regulation of silk synthesis.
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First steps towards a world monograph of the spider family Leptonetidae
Joel Ledford	California Academy of Sciences Entomology San Francisco, CA
Carles Ribera	Universitat de Barcelona Biologia Animal Barcelona, Catalonia
Byung-Woo Kim
Shuqiang Li
Charles Griswold	California Academy of Sciences Entomology San Francisco, CA
Recent revisionary work has dramatically improved our understanding of species level diversity in the Leptonetidae, particularly in East Asia and North America. However, most leptonetid genera remain poorly characterized and phylogenetic relationships within the family are unexplored. As the rate of species discovery accelerates, there is a need to better define leptonetid genera in order to provide a taxonomic foundation for future studies and produce a scaffold for evaluating biogeographic and evolutionary patterns. Here we present the first assessment of leptonetid relationships based on a combination of molecular and morphological data including exemplars for most described genera worldwide. Morphological characters supporting major clades are discussed and an overview of leptonetid biogeography is provided.
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Some die that others live: death by Ichneumonid
Robin E Leech	Edmonton, Alberta, Canada
Joanne Bovee
The larvae of ichneumonid parsitoids are infrequently attached to the upper, anterior parts of the abdomen of Araneus species (Araneae: Araneidae) and other immature spiders. Very rarely are these parasitoids reared from the larval stages to the pupa to the adult. Araneus gemmoides Chamberlin & ivie immatures (2nd or 3rd instar), with an ichneumonid parasitoid larva attached, were photographed at extreme close-up distances starting in April. The spiders are about 3 mm long or less. Normally, this spider would hatched from the egg the previous June (2-year life cycle here), and would be at least 6-9 mm in body length. Chemicals issued by either the larva, and/or the mother wasp, inhibit ecdysis. A series of photos shows the larva growing larger, killing and abandoning the spider's shrivelled body, the parasitoid pupa in a cocoon, through to the adult of Polysphincta koebelei Howard. Araneus gemmoides is a new host for this parasitoid, and this is the first record for Polysphincta koebelei in Canada.
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Firefly Flashing and Jumping Spider Behavior
Skye M Long	University of Massachusetts Amherst Organismic Evolutionary Biology Amherst, MA USA
Sara Lewis
Leo Jean-Louis
George Ramos
Jamie Richmond
Elizabeth Jakob	University of Massachusetts Psychology Amherst, MA USA
Bioluminescent flashing in fireflies, which is primarily a sexual signal, is known to deter some predators while attracting others. We tested whether flashing serves an antipredator function against the jumping spider, Phidippus princeps. Because spiders are likely to encounter resting fireflies during the day, we first documented that disturbed adult fireflies (Photuris sp.) flash in daylight. We then conducted three experiments to examine the influence of flashing on spider behaviour. (1) We tested whether attacking spiders were startled by the sudden onset of a flashing light by securing crickets next to an LED. Spiders attacked crickets regardless of whether the light flashed or not. (2) Using choice tests we determined whether flashing lights attracted or deterred spiders from attacking prey. Spiders more often attacked crickets next to a flashing LED versus an LED that was either off or glowed steadily. (3) Many firefly species are distasteful, and therefore we tested whether flashing lights facilitate avoidance of unpalatable prey with experience. We compared how attack rates changed after seven encounters with unpalatable prey associated with either flashing or unlit LEDs. Spiders in the two treatments were equally likely to attack the prey during their first encounter, but spiders exposed to flashing LEDs were significantly less likely to attack unpalatable prey by their seventh trial. We conclude that bioluminescent flash signals may increase attack rates by predatory jumping spiders, but may also facilitate learning about unpalatable prey. Thus, the costs and benefits of flashing will depend on the prevalence of firefly palatability.
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Diversity in Darkness: Phylogeography of the troglobiotic millipede Tetracion Hoffman (Callipodida, Abacionidae)
Stephanie F Loria	Sewanee The University of the South Biology Sewanee, TN
Kirk S Zigler
Julian J Lewis	J Lewis and Associates Biological Consulting Clarksville, IN, USA
Millipedes are an understudied group. Little is known about their ecology, life history, and genetic diversity. Particularly neglected are the cave millipedes of eastern North America. Understanding the patterns and processes that determine their distribution in this region is an area of recent research. Here, we present a phylogeographic study of the cave-obligate (troglobiotic) millipede Tetracion (Callipodida: Abacionidae). This genus inhabits caves on the Cumberland Plateau in Tennessee and Alabama, a hotspot for cave biodiversity. Three species have been described: T. jonesi from Alabama, T. antraeum from northern Alabama and southern Tennessee, and T. tennesseensis from south-central Tennessee. To examine genetic divergence within and between species in this genus we sequenced part of the mitochondrial cytochrome oxidase 1 gene from 53 specimens from 11 caves across the ranges of T. antraeum and T. tennesseensis. We found: (1) 7.9-8.6% genetic divergence between T. tennesseensis and T. antraeum, (2) little genetic variation within each species, and (3) a total of ten haplotypes (six in T. tennesseensis and four in T. antraeum) that were either restricted to individual caves or found in geographically nearby caves. Our results are consistent with previous morphology-based species definitions showing T. tennesseensis and T. antraeum belonging to distinct taxa. They also suggest that gene flow is limited between caves as the majority of haplotypes are restricted to a single cave. Our research contributes to the growing body of phylogeographic information about cave species on the Cumberland Plateau, and provides a point of comparison for future studies of troglobionts.
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Timing of sperm activation in a funnel-weaving spider (Agelenidae)
Samaa Lutfi	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Sabah Gagnon	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Anne Danielson-Francois	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Spiders have an unusual reproductive system because unlike most organisms that transfer actively swimming sperm, spider sperm remains encysted (immobile) until activated in the female spermatheacae. We examined the timing of sperm activation in the funnel-weaver Agelenopsis pennsylvanica (Agelenidae). Penultimate spiders were collected from the natural areas surrounding the University of Michigan-Dearborn. To observe the timing of sperm activation, staged matings between virgin spiders were conducted in the laboratory and females were frozen at different time increments after mating. The sperm stored in the spermathecae was found to be in different morphological states. We found that females frozen immediately after mating had higher percentages of encysted sperm compared to females frozen hours or days later. A more thorough understanding of sperm activation will help shed light on the unique and understudied reproductive system of spiders.
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Jumping spider phylogeny, continued: more genes, more species, more resolution (Araneae: Salticidae)
Wayne P Maddison	University of British Columbia Zoology Vancouver, BC Canada
Melissa R Bodner
New molecular data from more species and more genes continues to resolve salticid phylogeny. Previous studies have used the genes 28s, Actin 5C, 16sND1, 18s, CO1, Histone 3, and Ef1-alpha, with 28s showing the clearest phylogenetic signal. To these we add the wingless gene, wnt-8 and myosin. Preliminary analyses shows wingless results are strongly concordant with those of 28s; myosin is promising but sequenced from only a few species to date. Together these confirm many of the previous results, and add some deep salticoid resolution, including an apparent clade of plexippoids, aelurilloids, salticines, leptorchestines and euophryines. Well-supported placements are found for cocalodines and the ant-like Eburneana. Most problematic are the strange Agorius and Synagelides, whose placements differ among genes.
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When eating your young isn't a bad thing: Context-dependent eggsac abandonment and filial cannibalism in the wolf spider, Pardosa milvina
Megan F Marchetti
Matthew H Persons	Susquehanna University Biology Selinsgrove, PA
Parent-offspring conflict theory predicts that animals should allocate parental effort to maximize lifetime reproductive success. Iteroparous animals should be sensitive to offspring quality and withhold parental care for poor quality current offspring if it jeopardizes future reproduction. Animals should therefore be less sensitive to offspring quality when future reproduction is unlikely and maximize allocation of parental care late in life. The wolf spider, Pardosa milvina, demonstrates extensive parental care; however they also occasionally abandon or cannibalize their eggsacs. In this study we tested the effects of eggsac damage and production of a previous eggsac on eggsac abandonment and cannibalism. Treatment groups were randomly assigned for first eggsacs based on damaged or undamaged, and second eggsacs based on treatment of the previous eggsac (N=204). After assigning treatments, we monitored daily eggsac production, eggsac abandonment, cannibalism, protection and repairing behavior for first and second eggsacs. We found that younger females with first eggsacs were significantly more likely to abandon and cannibalize damaged eggsacs compared to unmanipulated eggsacs, however females with second eggsacs were insensitive to eggsac damage. Females also spent significantly more time protecting but not repairing or searching for second eggsacs compared to first and did not vary eggsac protective or repairing behavior based on damage. These results largely support the predictions of parent-offspring conflict theory that indicate that investment should increase and parents should be less sensitive to offspring quality late in life.
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Pseudoscorpions break all the rules. Part 1: Drastic reductions in size of mitochondrial RNA genes
Susan E Masta	Portland State University Biology Portland, OR USA
Sergey Ovchinnikov	Portland State University Biology Portland, OR USA
We have found that pseudoscorpions possess mitochondrial genomes that differ drastically from those of most other arthropods. Although protein-coding gene arrangement is broadly conserved among arthropods, some lineages of pseudoscorpions show rearranged genomes. They also possess extremely short RNA-coding genes. We have inferred the secondary structures for all of their RNA genes (transfer RNA and ribosomal RNA). We find that, compared with other chelicerates (and arthropods in general), these structures have lost entire helices in some regions and have greatly reduced helices in other regions. We use mitogenomic data to determine the evolutionary position of pseudoscorpions, and find surprising, but very well supported, relationships.
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Evolutionary analysis of venom gland gene expression in brown and black widow spiders.
Caryn A McCowan	University of Massachusetts Lowell Biological Sciences Lowell, MA
Jessica E Garb	University of Massachusetts Lowell Biological Sciences Lowell, MA
Venoms have evolved as a means for an animal to quickly disable a victim for feeding and for defensive purposes. The venoms of widow spiders (genus Latrodectus) are composed of complex mixtures of proteins, several of which possess potent neurotoxic activity. Despite their biomedical significance, the composition, diversity and evolutionary origins of these toxins remains largely unstudied. We constructed a cDNA library from venom gland tissue of the brown widow spider, Latrodectus geometricus, in order to identify Expressed Sequence Tags (ESTs) that code for toxin proteins. In addition, we performed a comparative analysis of toxins and venom-specific proteins from related species, including the black widow spider (Latrodectus hesperus). With our data we constructed phylogenetic trees to understand the evolution of these proteins. Our results demonstrate the molecular diversity of spider venom as well as identifying toxins with relevant medical functions.
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Orb-weaving spiders accumulate toxic heavy metals in southeastern Michigan
Samantha Michaels
Amneh Awad
Anne Danielson-Francois	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Spiders are top invertebrate predators in terrestrial food webs and yet little is known about whether they bio-accumulate significant levels of anthropogenic pollutants such as heavy metals. In this study we collected orb-weaving spiders and environmental samples from 10 sites along the lower branch of the Rouge River as well as from two more pristine sites near the start of the middle Rouge River: Johnson Creek in Northville and the Huron River in Pinckney. The Rouge River sites were sampled from June to August to observe any short and long-term changes in the soil and water quality. The spiders and environmental samples were analyzed for toxic heavy metals using inductively coupled plasma mass spectrometry (ICP-MS). We found detectable levels of toxic heavy metals in both spiders and environmental samples collected along the Rouge River in southeastern Michigan. This result suggests that orb-weaving spiders may be sensitive to anthropogenic pollution and they should be considered when restoring wetland ecosystems.
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Integrating and Sharing Biodiversity Data Online: Museum Science and International Collaboration in the Age of Cybertaxonomy
Jeremy Miller	Netherlands Centre for Biodiversity Naturalis Department of Terrestrial Zoology Leiden, The Netherlands
DinhSac Pham
In the Natural History museum setting, missions include building and sharing collections, training students, and accumulating data for publications in taxonomy, phylogenetics, and biodiversity. Collecting expeditions designed around structured sampling can reveal critical information about the World’s most diverse communities of plants and animals while generating raw material for studies in taxonomy and phylogenetics. New developments in communication and technology are revolutionizing the way we collect, organize, and share information. Synergies among all these activities can lead to a holistically integrated research program that confronts the taxonomic impediment in an era of biodiversity loss and democratizes access to scientific data. I report on the results of a recent collecting expedition to Vietnam.
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Fine Structural Aspects of Dragline Silk Processing in the Valve and Nozzle of the Ampullate Gland of the Spider Nephila clavata
Myung-Jin Moon	Dankook University Biological Sciences Cheonan, Korea
Hoon Kim	Dankook University Biological Sciences Cheonan, Korea
Jong-Gu Park	Dankook University Biological Sciences Cheonan, Korea
As the feedstock flows through the funnel of the ampullate duct, the droplets coalesce and are progressively stretched out by elongation flow to form silk filaments, and finally the polymerized dragline silk fibers are produced at the spigot on the anterior spinneret. Spiders can easily modify the spinning conditions by moving speed, and the diameter of the silk can be controlled by the valve located at the end of the duct. Here we investigate fine structural characteristics of dragline silk processing in the valve and nozzle of the major ampullate gland in Nephila clavata using various electron microscopic visualizations. The numerous cuticular cavities are distributed from the middle part of the third limb to the valve, and flask-shaped cells in the epithelium extend to the exocuticle of the duct through these cavities. In addition, we could find detailed cuticular grooves on apical surface of the third limb which are distributed with helical pattern of rifling. Accordingly, the major procedure for the conversion of the liquid feedstocks into insoluble dragline silk seems to be accomplished at the third limb near the valve, and both of the cuticular cavities and rifling grooves seem to contribute to facilitate the rapid conversion of the liquid feedstocks into an insoluble silk thread.
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Experience with chemotactile cues indicating female feeding history impacts male courtship investment in the wolf spider Schizocosa ocreata
Brian Moskalik	College of the Holy Cross Biology Worcester, MA
George W Uetz	University of Cincinnati Biological Sciences Cincinnati, OH USA
Male fitness is often determined by the ability of the male to gain access to multiple mates, although in spider species that exhibit sexual cannibalism, males might increase their likelihood of being cannibalized with each encounter. The risk of cannibalism should therefore create selection for males who are able to perceive potential risks associated with mating encounters. We studied male Schizocosa ocreata wolf spiders to determine whether they use chemotactile cues (silk, excreta) of females as indicators of potential risks, and how these cues affected subsequent male courtship behaviors. Female treatments included satiated females vs. starved females, as well as a treatment where females had recently cannibalized a male S. ocreata. We performed experiments to assess if males: 1) alter courtship investment in response to female chemotactile cues indicating potential risks associated with different female feeding treatments; and 2) how male experience with female chemotactile cues affected courtship investment in subsequent female encounters. Results indicate that at a first encounter, males do not vary courtship investment (number of bouts, duration and vigor) with different female feeding treatments. However, during subsequent encounters with female chemotactile cues, male behaviors varied, depending on female feeding treatment and experience with chemosensory cues previously encountered.
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Can spiders recognize their own silk?: Variation in silk deposition in response to self and conspecific silk in the wolf spider, Pardosa milvina (Araneae; Lycosidae)
Michael ODonovan
Matthew H Persons	Susquehanna University Biology Selinsgrove, PA
Silk is an important communication medium for the wolf spider Pardosa milvina (Hentz 1844). Both sexes produce silk as they move through the environment. This silk may function in species recognition, sex identification, mating status assessment or to convey information about body condition. Silk is also energetically costly; therefore, males and females may benefit by selectively depositing silk to maximize communication efficacy but minimize cost. Spiders may also benefit by discriminating between their own or another conspecific’s silk. Silk-mediated self-recognition could allow spiders to identify areas that they have previously visited, competitively block silk advertisements from sexual rivals, or minimize redundant signaling in an area. We tested if male and female P. milvina wolf spiders can discriminate between their own silk and the silk of another spider of the same sex. Using a paired design, we quantified male and female deposition of three silk types: draglines, cord silk, and attachment disks on substrates containing either their own silk or the silk of a conspecific (N = 51). Both males and females significantly increased dragline and cord silk deposition on substrates containing same-sex conspecific rather than their own silk with males producing more cord silk than females. Males increased attachment disk deposition on conspecific male silk compared to their own while females showed the opposite response, decreasing attachment disk deposition on conspecific female silk. Wolf spiders can recognize their own silk with small but significant qualitative and quantitative differences in silk deposition by males and females.
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Molecular and mechanical comparisons of cob-web weaver spiders (Theridiidae) dragline silk.
Patrick A Oley	Washington and Lee University Biology Lexington, VA USA
Peter M ODonnell	Washington and Lee University Biology Lexington, VA USA
Michael H White	Washington and Lee University Biology Lexington, VA USA
Matthew Collin	University of California Riverside Biology Riverside, CA USA
Nadia A Ayoub	Washington and Lee University Biology Lexington, VA USA
Spider dragline silk is one of the strongest biological materials, approaching the tensile strength of steel. However, mechanical properties of dragline silks vary significantly among the different species measured thus far. In this study, we compared the molecular and mechanical properties of dragline silk of three cob-web weaving species (Theridiidae): Latrodectus hesperus, L. geometricus, and Steotoda grossa. We found that the Latrodectus species produce dragline silk twice the tensile strength of S. grossa dragline, which spans the range of measured tensile strengths for all spiders (Araneae). The close relationship of these species offers the opportunity to identify molecular changes associated with this dramatic shift in tensile strength. Thus, we constructed a cDNA library for S. grossa in order to characterize genes that encode the protein components of dragline silk. We will compare these protein sequences to previously published sequences for Latrodectus dragline.
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Humidity affects the extensibility of an orb-weaving spider’s viscous thread droplets
Brent D Opell	Virginia Tech Biological Sciences Blacksburg, Virginia
Shannon E Karinshak
Mary A Sigler
The prey capture threads found in most spider orb-webs rely on viscous droplets for their stickiness. Each droplet is formed of a central mass of viscoelastic glycoprotein glue surrounded by an aqueous covering, both of which incorporate hydrophilic components. We found that the extensibility of droplets on Larinioides cornutus threads increased as humidity increased. However, the deflection of the droplets’ supporting axial lines did not change, indicating that atmospheric water uptake increases glycoprotein plasticity, but not glycoprotein adhesion. The extensibility of droplets, along with that of the thread’s supporting axial fibers, is responsible for summing the adhesion of multiple thread droplets. Therefore, daily changes in humidity have the potential to significantly alter the performance of viscous threads and orb-webs.
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Ovarian Development in the Western Black Widow Spider, Latrodectus hesperus
Wendy Ouriel
Merri L Casem	California State University Fullerton Biological Science Fullerton, CA USA
Black widow spiders (Latrodectus hesperus Chamberlin & Ivie (1935)) have the potential to generate multiple egg sacs containing hundreds of eggs over a period of several months, often from a single copulation. This feat can only be accomplished if there is a steady supply of oocytes. In this study, ovarian tissue was isolated from black widow spiders at different stages of ovarian development and examined by light and electron microscopy. Oocytes at varying stages co-exist as clusters on the spider’s ovary where they attach to the muscular ovarian wall by way of a multicellular stem-like structure and project into the abdominal cavity. Pre-vitellogentic oocytes are characterized by a homogeneous cytoplasm with numerous mitochondria. During vitellogenesis, the oocytes increase in size accompanied by the accumulation of yolk granules. The number, size, and organization of the yolk granules change over time. In the gravid spider, the oocytes separate from the ovary wall and are loosely aggregated within the abdomen of the spider. Following oviposition, the fertilized eggs become surrounded by a hardened chorion composed of small spherical granules. Overall, the pattern of ovarian development in the black widow spider is similar to that documented in other spiders. We are seeking to determine the cellular processes involved in the accumulation of yolk material, the possible role of apoptosis in the separation of the oocytes from the stem, the origins of the chorion material and the mechanism that moves mature oocytes from the abdominal cavity to the gonopore.
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Pseudoscorpions break all the rules. Part 2: Mitochondrial protein-coding genes relax the rules of amino acid use
Sergey Ovchinnikov	Portland State University Biology Portland, OR USA
Susan E Masta	Portland State University Biology Portland, OR USA
The mitochondrial genomes of the pseudoscorpions we have sequenced possess many mutational changes compared to other arthropods. Our analyses reveal that these genomes possess a cytosine and adenine bias on their major coding strand, which is the typical condition found in other arthropods. However, their patterns of amino acid use differ dramatically from other arthropods and most chelicerates. We find very high levels of amino acid interchangeability in pseudoscorpion mitochondrial genes. Most surprisingly, we find high levels of interchangeability between functional groups. We compare and contrast the amino acid use patterns of pseudoscorpions with other arthropods, and discuss how amino acid use may influence phylogenetic reconstruction.
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Seasonal Dynamics and Biomass of Spiders and Other Soil Invertebrates in Oak Forests of Black Rock Forest, NY
Vladimir Ovtcharenko	Hostos Community College of CUNY Natural Sciences New York, NY, USA
Boris Zakharov	LaGuardia Community College of CUNY Natural Sciences New York, NY, USA
The Black Rock Forest (BRF) is located in New York State about 60 miles north of New York City. Our study is part of a large, multistage BRF project: "Ecosystem Consequences of Dominant Taxon Loss: the Future of Oak Forests." Spiders and other soil invertebrates studied on two already designated sets of plots: a pilot project area and a main project area. A pilot project includes two areas: fenced and unfenced. The fenced area protects vegetation against different wild animals, mostly deer. We collected in the oak forest 210 species of spiders and also representatives of different orders of invertebrates. Preliminary data shows that spider’s biomass has an interesting correlation between fenced territory and area outside the fence, hence the spider’s biomass outside of the fenced area in June is reaching its maximum and is slightly higher than the spider’s biomass inside of the fenced area. This data suggests that ground inhabiting spider’s community is not significantly affected by herbivorous mammals, such as deer. In June the spider’s biomass outside of the fenced area shows a very strong correlation with the type of experimental plots: the lowest spider’s biomass was on the plot with all oak trees girdled, the next spider’s biomass was on the plot with all oak trees girdled on 50%, next all non-oaks trees girdled and the maximum spider’s biomass was recorded on the control plot. This data definitely shows that the state of dominant trees health plays important role on the species diversity and the spider’s biomass.
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Fine Structural Aspects on the Ganglionic Neurons in the Golden Silk Spider, Nephila clavata (Araneae: Nephilidae)
Yong-Ki Park	Dankook University Biological Sciences Cheonan, Korea
Sung-Chan Yang	Dankook University Biological Sciences Cheonan, Korea
Myung-Jin Moon	Dankook University Biological Sciences Cheonan, Korea
Since arachnids are distinguished from insects by the fact they have eight legs and have no antennae or wings, the spider's CNS is made up of two relatively simple ganglia, or nerve cell clusters, connected to nerves leading to various muscles and sensory systems. The central nervous system (CNS) of the golden silk spider, Nephila clavata consists of a dorsal supraesophageal ganglion and a ventral subesophageal mass. A number of nerves arise from these ganglia and spread out to the body, making up the peripheral nervous system. In N. clavata, the nerve cells in the supraoesophageal ganglion are packed in frontal and dorsal and lateral regions, but the nerve cells of the subesophageal mass are only restricted to the ventral and ventrolateral regions. The central body, which is recognized as an important association center for web building, is isolated at the rear of the protocerebrum and two types of cells are identified on the basis of fine structural characteristics. The globuli cell (Type-A cell) has a large nucleus and poorly stained cytoplasm, whereas the Type-B cell has a granular chromatin and clear cytoplasm.
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Trap design choice of Loxosceles reclusa
Jennifer L Parks
William V Stoecker
Pest control without the use of chemicals leaves a consumer with limited options. Glue traps are normally used in circumstances where pesticide use is being avoided. Three-dimensional shapepreferences of the brown recluse spider, Loxosceles reclusa, were investigated using 4 different glue trap shape designs. These four shape designs were tested using pairwise shape comparisons. The leading trap design was a flat glue trap, which can pose risks in homes with children and pets. Cardboard, a material that brown recluses are known to prefer were used to make the traps more alluring.
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Comparing two trapping methods for capturing wandering spiders: pitfall vs. ramp traps.
LBrian Patrick	Dakota Wesleyan University Department of Biological Sciences Mitchell, SD USA
Ashton Walter	Mount Marty College Department of Biology Yankton, SD
Pitfall traps are a common sampling method used to collect wandering spiders in a variety of habitats, and these traps require soil disturbance to properly set the trap with the top of the trap at the level of the soil surface. However, not all sampling locations are amenable to soil disturbance, either because there is no soil in which to dig (e.g., rock surfaces), or because soil disturbance is not allowed or it is very difficult to obtain permits for soil disturbance (e.g., US national parks). We tested the efficacy of a new trap design called ramp traps and developed by researchers in Canada, against traditional pitfall traps. In two fields of the Fort Pierre National Grasslands, SD, we ran parallel transects of pitfall and ramp traps for two sampling periods of two weeks each, then counted the number of species and the number of individuals of each species in each trap. Ramp traps captured significantly more species and more individuals, resulting in higher species diversity compared to pitfall traps. However, the species composition caught in ramp and pitfall traps varied, with a small number of species captured only in pitfall traps, and a very small number of species captured only in ramp traps. Despite these subtle differences, ramp traps generally outperformed pitfall traps and may be easily moved to different locations with little or no soil disturbance. Our results indicate that ramp traps would be a viable trapping method, particularly in areas where soil disturbance is not allowed.
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Interactions of transgenic Bacillus thuringiensis insecticidal crops with spiders (Araneae)
Julie A Peterson	University of Kentucky Department of Entomology Lexington, KY USA
Jonathan G Lundgren
James D Harwood	University of Kentucky Department of Entomology Lexington, KY USA
Genetically modified crops expressing insecticidal proteins from Bacillus thuringiensis (Bt) have dramatically increased in acreage since their introduction in the mid-1990’s. Although the insecticidal mechanisms of Bt target specific pests, concerns persist regarding direct and indirect effects on non-target organisms. In the field, spiders may be exposed to Bt toxins via multiple routes, including phytophagy and pollenivory, consumption of Bt-containing prey, and soil exudates in the detrital food web. Beyond direct toxicity, Bt crops may also have indirect impacts, including pleiotropic and prey-mediated effects. Here, we comprehensively review the literature and use meta-analyses to reveal that foliar spider abundance is unaffected by Bt corn and eggplant, while cotton and rice revealed minor negative effects and there were positive effects from potato. Moreover, the soil-dwelling community of spiders was unaffected by Bt corn and cotton, while positively impacted in potato. However, Bt crops had higher populations of both foliar and epigeal spiders compared to insecticide-treated non-Bt crops. The current risk-assessment literature has several caveats that could limit interpretations of the data, including lack of taxonomic resolution and sampling methods that bias the results in favor of certain spiders. These families responded differently to Bt crops and spider responses to insecticides are species- and toxin-specific, thus highlighting the need for greater taxonomic resolution. Bt crops have become a prominent, and increasingly dominant, part of the agricultural landscape; understanding their interactions with spiders, a diverse and integral component of agroecosystems, is therefore essential.
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Adaptive radiation on a continental scale: Ecomorph convergence in jumping spiders
Edyta K Piascik	University of British Columbia Zoology Vancouver, BC Canada
Wayne P Maddison	University of British Columbia Zoology Vancouver, BC Canada
Adaptive radiations contribute to diversification of life on earth, yet the question remains as to whether patterns of species differentiation are a result of predictable evolutionary processes or historical contingencies. My research asks whether phylogenetically independent communities of jumping spiders (Salticidae) predictably converge in morphospace or whether they are influenced by historical contingencies. To achieve samples not biased by selective species description and to isolate a single ecological context I propose to intensely sample salticids at single sites in comparable tropical rainforests in South America and Australasia (4 sites total) while recording microhabitat data (foliage, litter, tree trunks). I will combine geometric morphometric data with molecular phylogeny and habitat specificity to show whether different sites show independent but similar diversifications in morphology correlated with ecology ("ecomorphs"). This would demonstrate quantitatively that large scale continental diversifications can behave as predictably as smaller diversifications. On the other hand, if strong differences among sites imply contingencies, I will use the dated phylogeny to explore whether relative clade youth could explain lesser diversification. My research will provide a rare example of a large scale study of intercontinental community-level patterns to distinguish convergence and contingency using a comparative phylogenetic framework.
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Not so banal after all; latest evidence on Loxosceles diversity in Canary Islands and Northwestern Africa
Enric Planas	Universitat de Barcelona Biologia Animal Barcelona, Catalonia
Carles Ribera	Universitat de Barcelona Biologia Animal Barcelona, Catalonia
The venomous spider genus Loxosceles has a widespread distribution, and the vast majority of its species are concentrated in North and South America. The cosmopolitan Loxosceles rufescens (Dufour, 1820) has its original distribution range in the Mediterranean basin, and has been the only valid representative of the genus in this area until the recently discovered Loxosceles mrazig Ribera & Planas, 2009 from Tunisia. Recent collecting trips carried out in Morocco and Canaries provided us with abundant material of Loxosceles. In this poster, we present the preliminary results on biogeography and taxonomy of this genus in the Mediterranean and Canary Islands, based on morphology and molecular data. Canary Islands harbor an endemic group of Loxosceles species. Until now we have identified 5 endemic species: 1 from Fuerteventura and Lanzarote, 2 from Tenerife and 2 from Gran Canaria. Our data suggest a single colonization event to the eastern Canary Islands (Fuerteventura and Lanzarote) and a posterior interinsular colonization to Gran Canaria and Tenerife. Within the L. rufescens lineage, preliminary results, including individuals from the type locality and a large number of specimens from the Mediterranean Basin, show several independent evolutionary lineages that could suggest a cryptic speciation.
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Shifts in female silk deposition in the presence of composite silk from conspecifics in the wolf spider Pardosa milvina (Araneae; Lycosidae)
Michael J Platt
Matthew H Persons	Susquehanna University Biology Selinsgrove, PA
Males and females of the wolf spider, Pardosa milvina (Hentz, 1844), produce silk draglines to attract prospective mates. Silk is energetically costly to produce so females may benefit by selectively investing in silk advertisements based on mate availability and the presence of other female silk. Females may also benefit by discriminating among silk from two different males or silk from a female vs. a male. Information about spider sex or individual identity through draglines could allow females to use silk to attract specific males, assess local sex ratios, or minimize silk deployment by exploiting the advertisements of other females. Females may also benefit by assessing the order of silk deposition by conspecific males and females. Using silk, females could assess whether males are currently pursuing a female or if females were in the area last. We measured female silk deposition over a 30-minute period in the presence of silk from seven different combinations of conspecific males and females that deposited silk over different time periods and in different sequences. Females deposited significantly more silk on blank substrates and reduced silk deposition when encountering silk from other spiders. Females showed more silk deposition in the presence of silk from a single female rather than multiple females or males and did not discriminate between the order of silk deposition for males and females. Females mediate silk deposition based on the different combinations of conspecific silk but females varied in the quantity of different silk types depending on the context.
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The personality compositions of social spider groups determine the nature of interspecific interactions within their webs
Jonathan N Pruitt	University of California Davis Center for Population Biology Davis
Maud Ferrari
Susan E Riechert
Although the study of ecological interactions often takes into account functional variation between species, intraspecific variation is commonly ignored. Here, we investigate the importance of an intraspecific polymorphism in shaping interspecific interactions in a habitat-building species. Colonies of the social spider Anelosimus studiosus provide habitat for dozens of arthropod species, and colony members exhibit markedly polymorphic behavioural tendencies (BT – “aggressive” or “docile”). We manipulated the phenotypic compositions of colonies (100% aggressive, 50% aggressive 50% docile, 100% docile) and measured the nature and magnitude of interactions between A. studiosis and two heterospecific web associates, Larinioides cornutus and Agelenopsis emertoni. We found that BT composition significantly affected the outcome of interspecific interactions: changing the relationship between A. studiosus and its web associates from an ammensalism (where A. studiosus experiences reduced fecundity and survival) to a commensalism or mutualism. Although BTs have received much attention in recent years, our study is the first to demonstrate the importance of BTs in mediating the nature of species interactions. Implications for adaptive social group composition and eco-evolutionary dynamics are discussed.
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Captive rearing of the orb-weaving spider Araneus diadematus
Kori E Quatermass	Portland State University Biology Portland, OR USA
Matthew W Mulhern	Portland State University Biology Portland, OR USA
Susan E Masta	Portland State University Biology Portland, OR USA
Previous studies have reported difficulties raising orb-weaving spiders in captivity. We experimented with different methods of rearing Araneus diadematus (Clerck 1757) in captivity. We collected spider egg sacs from the wild and maintained them in vials in the lab, then raised spiders from hatching until maturity. To assess life-history characteristics, we recorded the length of time between molts and the number of days to adulthood, for both males and females. We also compared survival rates of early instars for spiders kept in groups versus spiders kept in individual vials. We found that spiders spent significantly longer in the second instar relative to other instars. Spiders took an average of 115.88 ± 13.60 days to reach adulthood. More males reached adulthood than females. Spiders kept in groups tended to mature earlier than those kept in individual vials.
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Feeding preferences of solifuges (Arachnida: Solifugae) and their trophic position in desert communities.
Kristie Reddick	Texas AM University Entomology College Station, TX
Robert Wharton	Texas AM University Entomology College Station, TX
It is widely recognized that solifuges are important inter- and intraguild predators in arid and semi-arid ecosystems, but their role as a prey animal is not well understood. This talk will be an overview of feeding and prey studies designed to determine trophic position of solifuge arachnids in desert communities. This work was part of a larger study focused on the diversity and distribution of the solifuges of Kenya. It has been demonstrated that at least some solifuges have rejected prey items that were either too large, too heavily sclerotized, or which may have been protected by defensive chemicals. We present a feeding study that provides baseline data on solifuge ability to consume hard and toxic prey and possible preference between the two. Tenebrionid beetles, polydesmid millipedes, Danaus sp. pupae and Pachycondyla sp. were offered to 17 solifuges. All solifuges in the feeding study ate the termites that were used as a behavioral control, but only three individuals were able to eat both hard and toxic prey items repeatedly. Solifuges were more willing or able to eat toxic prey than hard. Additionally, by quantifying arthropod remains from burrowing owl pellets in the southwestern United States, we were able to determine owl prey preference among six orders of arthropods, including solifuges. Solifuges were the third most frequently encountered arthropod in the pellets, after caterpillars and beetles, and were also the third most abundant.
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Species discovery of millipeds in the Pacific Northwest with molecular anayses of Chelojulus (Julida, Chelojulidae) supporting yet another new species.
Casey H Richart	San Diego State University Biology San Diego, CA USA
Kristen N Emata	San Diego State University Biology San Diego, CA USA
William P Leonard	WSDOT Environmental Policy Olympia, WA USA
William A Shear	HampdenSydney College Biology HampdenSydney, VA, USA
Ongoing faunal surveys of Diplopoda in the Pacific Northwest since 2000 have resulted in the discovery of approximately 70 new species. Of these, a handful have been described and published including a new family, three new genera, and half a dozen new species. Among these discoveries was a 500 km range extension of the morphologically unique Julida genus Chelojulus sculpturatus from northern Idaho into the Willapa Hills of western Washington. Morphological discrimination of this species was not possible using standard gonopodal differentiation. Though the taxonomic absolute of gonopodal differences are not tested here using morphometric analyses, the newly discovered population as a unique species is tested using molecular analyses. The mitochondrial 16S and nuclear ribosomal 28S genes are used to test species limits in the genus Chelojulus. These gene trees support unique species for this group, with vicariance likely coinciding with orogeny of the Cascade Mountains around 5 MYA. Natural history of the group, as well as distribution in the mesic forests of the northern Rocky Mountains, including first state records for Montana, are also reported.
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Australian Assassins: phylogeny, diversity and biogeography of the Australian assassin spiders (Araneae: Archaeidae)
Michael G Rix	Western Australian Museum Terrestrial Zoology Perth, Western Australia, Australia
Mark S Harvey	Western Australian Museum Terrestrial Zoology Perth, Western Australia, Australia
The 'assassin spiders' of the family Archaeidae are an ancient and iconic lineage of basal araneomorph spiders, remarkable for their extraordinary appearance, specialised ecology, evolutionary antiquity and endemism on the southern continents. The Australian archaeid fauna is newly revised taxonomically and phylogenetically, revealing a diverse and highly endemic fauna characterised by mostly short-range endemic, reciprocally allopatric species. Molecular phylogenetic analyses provide strong evidence for a monophyletic clade of Australian Archaeidae and for the presence of three major endemic lineages, each with non-overlapping distributions in north-eastern Queensland, mid-eastern Australia and southern Australia, respectively. Phylogeographic results highlight the mode and tempo of archaeid speciation in Australia during the Miocene, and provide compelling evidence for the diversification of clades due to the Tertiary contraction and fragmentation of Australia's mesic biomes. Assassin spiders are among the most useful animal models for exploring biogeographic processes in mesic Australia, with the potential to provide new and significant insights into the evolution of the continent’s remaining rainforests, wet sclerophyll forests and southern-temperate heathlands.
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Inferring species trees from gene trees in a radiation of California trapdoor spiders (Araneae, Antrodiaetidae, Aliatypus)
Jordan Satler	San Diego State University Biology San Diego, CA USA
James Starrett	University of California Riverside Biology Riverside, CA USA
Cheryl Hayashi	University of California Riverside Biology Riverside, CA USA
Marshal Hedin	San Diego State University Biology San Diego, CA USA
The trapdoor spider genus Aliatypus (Mygalomorphae, Antrodiaetidae) encompasses twelve described species, eleven of which are endemic to California. Several Aliatypus species show disjunct distributional patterns in California (some are found on both sides of the vast Central Valley), and the genus as a whole occupies an impressive variety of habitats. DNA sequence data were collected from seven gene regions, including two newly developed for spider systematics. Bayesian inference (in individual gene tree and species tree approaches) recovered a general “3 clade” structure for the genus (A. gulosus, californicus group, erebus group), with three other phylogenetically isolated species differing slightly in position across different phylogenetic analyses. For multiple species spanning the Central Valley, explicit hypothesis testing suggests a lack of monophyly for regional populations (e.g., western Coast Range populations). In addition, phylogenetic evidence clearly shows that syntopy is restricted to distant phylogenetic relatives, consistent with ecological niche conservatism. Overall, this study provides fundamental insight into a radiation of trapdoor spiders found in the biodiversity hotspot of California.
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New fossil palpimanoids from the early Cretaceous of Spain, with a combined extant/fossil phylogenetic analysis of the superfamily Palpimanoidea
Erin E Saupe	University of Kansas Geology Lawrence, KS USA
Ricardo Perez-delaFuente
Paul A Selden	University of Kansas Paleontological Institute Lawrence, KS USA
Three palpimanoid fossils were recently discovered from early Albian (110 Mya) amber of Peñacerrada I (Burgos, Spain). These specimens present unique combinations of characters that ally them most closely with the Huttoniidae and Archaeidae/Mecysmaucheniidae. The fossil finds, with their distinctive amalgamation of palpimanoid characteristics, prompted a reevaluation of fossil and extant taxa traditionally assigned to Palpimanoidea. A parsimony-based phylogenetic analysis was conducted using an additional six fossil taxa previously described within the Archaeidae, †Lacunaucheniinae, Mecysmaucheniidae, †Micropalpimanidae, and †Spatiatoridae, and seven extant representatives from the families Archaeidae, Huttoniidae, Mecysmaucheniidae, Palpimanidae, and Stenochilidae. Results from the phylogenetic analysis will be discussed, including the placement and description of the new fossils and their paleobiogeographic significance.
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Sex but not prey availability drives seasonal variation in body condition in the wolf spider, Pardosa milvina
Jason M Schmidt	Miami University Zoology Oxford, OH USA
James D Harwood	University of Kentucky Department of Entomology Lexington, KY USA
Ann L Rypstra	Miami University Zoology Hamilton, OH USA
The physiological state of an organism likely varies in relation to environmental conditions. In particular, availability of food resources should have profound effects on the physiological state of animals. Predatory arthropods such as spiders are considered food limited and extremely polyphagous, which means they should eat any prey available to increase their chance of survival and reproduction. Therefore, we predicted that body condition should be correlated with increased encounter rates with prey. We conducted a field survey of the wolf spider, Pardosa milvina. Spiders were collected between May and October in two habitat types, corn and soybean fields. To assess changes in spider condition, we used the residual index from a regression of measurements of size of spiders, carapace width, and mass. Prey abundance was monitored in these same fields to track fluctuations in abundance within fields and between months sampled. Males were on average in poor condition as compared to females. Although body condition declined over the growing season, availability of potential prey increased. These results are consistent with previous characterizations of the sex roles of male and female Pardosa, where males forage less than females but are more active as they search for mates. From an ecological perspective, these results suggest that prey abundance is less important than other factors in this system in determining foraging success.
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Deep phylogenetic divergences in the harvestman genus Sabacon (Opiliones, Dyspnoi), with insights into Holarctic biogeography.
Axel L Schoenhofer	San Diego State University Evolutionary Biology San Diego, CA, San Diego County
Maureen McCormack
Jochen Martens
Nobuo Tsurusaki
Marshal Hedin	San Diego State University Biology San Diego, CA USA
Within the harvestman clade Dyspnoi, Nemastomatidae and Sabaconidae are present on all northern continents (i.e., north America, northern Asia and Europe), while other Dyspnoi families are restricted to two or fewer northern continents. Geographically widespread genera are rare in Dyspnoi, reflecting their poor dispersal abilities - an exception is the genus Sabacon, which is present on all three northern continents. A multigenic molecular phylogenetic analysis of Sabacon reveals several strongly supported biogeographic connections. For example, species from the eastern United States show connections to both Asia and Europe. Western US species only display Asian affinities, but on different time scales, pointing to repeated vicariance events over time. Taxonomic literature indicates that genetic clades correspond to morphologically distinct lineages that differ especially in genital morphology. At the regional level (e.g., western US, eastern US), our data suggests the presence of many cryptic species; denser geographic sampling and the collection of adult males is needed to further explore this diversity.
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Review of fossil Nephilidae
Paul A Selden	University of Kansas Paleontological Institute Lawrence, KS USA
The recent discovery of a female Nephila (N. jurassica) in middle Jurassic (c. 165 Ma) rocks of China has prompted a survey of all fossil Nephilidae. The nephilid fossil record consists of three extinct genera in Paleogene (c. 40 Ma) Baltic and Bitterfeld ambers, five Nephila species from Neogene (c. 16 Ma) Dominican amber and Nephila pennatipes from the Eocene (c. 34 Ma) of Florissant, Colorado. The Mesozoic record consists of Cretaraneus vilaltae from the Cretaceous (c. 130 Ma) of Spain. Supposed Cretaraneus from the Cretaceous of Brazil and China do not show the characters of the genus, and Archaeometa nephilina from the Carboniferous of England, described as resembling a Nephila, is probably not a spider. All fossil nephilids apart from N. pennatipes and N. jurassica are adult males. Restudy of N. pennatipes from Florissant confirms its identification. Nephila is renowned for its extreme sexual size dimorphism, and there has been debate concerning whether this is due to male dwarfism or female gigantism. Nephila jurassica is as large as many Recent Nephila females, but a male of this species had not been found until recently (May 2011). The talk will conclude with discussion of what, if anything, the male of N. jurassica tells us about the evolution of sexual size dimorphism in the golden orb-weaver spiders.
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The British Arachnological Society
Paul A Selden	University of Kansas Paleontological Institute Lawrence, KS USA
The British Arachnological Society was founded in 1968 from the British Spider Study Group. It has about 500 members around the world. The British Arachnological Society publishes a Newsletter and the Bulletin of the British Arachnological Society. In addition to receiving these publications, members enjoy indoor and field meetings, access to the Society’s extensive reprint and slide libraries, an exclusive web site which is a major online resource for arachnologists, and an email discussion group. In the near future, members will also have access to the Bulletin online. Overseas membership costs £18 (£19 via PayPal), and institutions can subscribe to publications for £30 (£32 by PayPal). Go to http://wiki.britishspiders.org.uk for further information. First published in 1969, the Bulletin is a quality, peer-reviewed publication covering all aspects of arachnology (except works primarily on Acari); it has three issues per year. Prospective authors are invited to submit their manuscripts through the online system at http://bas.msubmit.net.
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Silk biomechanics and energy absorption in spider orb webs
Andrew Sensenig	Tabor College Biology Hillsboro, KS USA
Sean Kelly	University of Akron Biology Akron, OH USA
Kimberly Lorentz	University of Akron Biology Akron, OH USA
Todd A Blackledge	University of Akron Biology Akron, OH USA
The kinetic energy of flying insect prey represents a formidable challenge for orb weaving spiders who rely on their webs to first absorb the kinetic energy of flight and then to adhere to insects. While spider silks are renowned for their exceptional material properties, the micron-sized diameters of threads also results in a low Reynolds number and hence viscous interactions with air. This led to the aerodynamic dissipation hypothesis that suggests that drag of silk threads moving through air plays a dominant role in how orb webs stop flying insects. However, evidence for the aerodynamic dissipation hypothesis is derived primarily from studies of single silk threads from Araneus. Here, we present a comprehensive study of how orb webs deform under prey impact for several species of Araneidae. We calculate energy dissipation budgets using data derived from high speed images of web deformation in conjunction with material tensile testing. Our findings emphasize the importance of the intrinsic work performed by silk molecules within radial threads, and downplay the role of aerodynamic dissipation and capture spiral deformations in many webs.
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East is east and west is west: Defensive chemistry of North American travunioid harvestmen
William A Shear	HampdenSydney College Biology HampdenSydney, VA, USA
Heather M Guidry	Virginia Military Institute Chemistry Lexington, VA USA
Tappey H Jones	Virginia Military Institute Chemistry Lexington, VA USA
Julian J Lewis	J Lewis and Associates Biological Consulting Clarksville, IN, USA
Maria Minor	Massey University Ecology Group Institute of Natural Resources Palmerston North, NZ
North American opilionids of the taxon Travunioidea are the subject of much recent systematic and phylogeographic research. Here we report on an apparent dichotomy in defensive chemistry between the eastern and western genera. Erebomaster and Theromaster species of the eastern US secrete a mixture of alkaloids dominated by anabaseine, while the western US genera, including Sclerobunus, Cryptomaster, Speleomaster, Metanonychus, Paranonychus and Speleonychus secrete N,N-dimethylphenylethylamine (pseudephedrine) as the major component. Preliminary results on southern hemisphere (New Zealand) triaenonychids (usually taken as the phylogenetic outgroup to travunioids) are preliminary, but they appear to secrete various alcohols and aldehydes, so are not of present help in polarizing this character on cladograms. At present we suggest that anabaseine secretion arose once, in the clade that consists of Erebomaster and Theromaster. Studies on European and east Asian travunioids are needed to complete the picture.
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Activity of male tarantulas (Brachypelma vagans) during the mating season
Cara Shillington	Eastern Michigan University Biology Ypsilanti, MI
Male tarantulas abandon their permanent retreat on reaching sexual maturity and search actively for reproductive females. To date, three studies have tracked male movement at field sites in Texas, but this is the first radio-telemetry study in Mexico. I tracked 16 male Brachypelma vagans in the state of Puebla during the mating season. Males were most active between 8pm and 2am which corresponded with times when females were near the entrance of their burrows. Average distance traveled was 33.4 m / day but there was a lot of variability among the males and several males remained in the same location for several days. Mortality rates were >50% and an additional 18% of males were lost due to equipment issues. Five males were seen in with or in close proximity to female burrows, but no actual mating was observed. In comparing rates of movement with radio-tracked male Aphonopelma anax in Texas, B. vagans had significantly lower rates but female burrows in Mexico were much more numerous.
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Multiple predator effects on the survival of Pardosa milvina (Araneae: Lycosidae)
Michael I Sitvarin	Miami University Zoology Oxford, OH USA
Ann L Rypstra	Miami University Zoology Hamilton, OH USA
The role of predation in food webs has frequently been investigated, but systems with multiple predators at the same trophic level have received less attention. Furthermore, multiple predator effects (MPEs) have traditionally been investigated with a non-predatory species as shared prey between predators. Here, we take advantage of the prevalence of intraguild predation among wolf spiders and a carabid beetle to evaluate how a predator responds to multiple predator risks. We first characterized the habitat domain and hunting mode of three predators (Hogna helluo, Rabidosa rabida, and Scarites quadriceps) and their shared prey, Pardosa milvina, in laboratory mesocosms. Habitat domain and hunting mode were then used to predict multiple predator effects (i.e., risk enhancement, risk reduction, and substitutability), which were evaluated by recording Pardosa survival in the presence of all combinations of the three predators. Predator combinations showed evidence of substitutability, risk enhancement, and risk reduction, though not all MPEs matched predictions based on habitat domain and hunting mode. Specifically, the treatment with Rabidosa and Scarites resulted in risk enhancement when substitutability was expected. Additionally, the MPE of Hogna and Scarites showed substitutability when risk reduction was predicted. Deviations from expected MPEs may be attributable to a lack of predation on Scarites by Hogna, and the possibility that habitat domain and hunting mode are not sufficient predictors of MPEs. This study provides insight into how multiple intraguild predators affect their prey, and raises interesting questions about the role of multiple predator effects in food webs.
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Early events in the evolution of spider silk genes
James Starrett	University of California Riverside Biology Riverside, CA USA
Jessica E Garb	University of Massachusetts Lowell Biological Sciences Lowell, MA
Cheryl Hayashi	University of California Riverside Biology Riverside, CA USA
Silk spinning is essential to spider ecology and has had a key role in the enormous diversification of spiders. Silk is composed primarily of proteins and studies on the genes encoding silk proteins have largely focused on the derived clade, Orbiculariae (orb-weavers), from the suborder Araneomorphae (‘true spiders’). Orb-weavers secrete multiple types of functionally distinct silks from a suite of silk fibroin genes. Underlying this extensive repertoire of silks is a history of duplication and subsequent divergence of silk genes. However, much of the phylogenetic diversity of spiders has yet to be sampled for their silk genes, leaving questions as to when silk gene duplications occurred and how these duplications allowed silks to take on new functions. In contrast to their distant orbicularian relatives, spiders of the suborders Mesothelae (segmented spiders) and Mygalomorphae (tarantulas, trapdoor spiders) have morphologically uniform silk glands and more generalized uses of silk. Given their simpler silk biology, these spiders are hypothesized to have less diversity of silk genes. Here, we report the results of constructing expression libraries from the silk glands of multiple mygalomorph species, a mesothele, and a non-orbicularian araneomorph, to uncover their surprisingly rich silk gene diversity. We relate the attributes of the newly discovered silk sequences to the ecological functions of the spiders. Furthermore, by performing gene-tree and species-tree analyses, we document the numerous silk gene duplications that occurred after the split between the Mesothelae and Opisthothelae (Mygalomorphae plus Araneomorphae).
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Cooperative kleptoparasitism? Living in groups increases foraging efficiency in Argyrodes miniaceus (Argyrodinae, Theridiidae).
Yong-Chao Su	University of Kansas Ecology and Evolutionary Biology Lawrence, KS USA
Deborah Smith	University of Kansas Ecology and Evolutionary Biology Lawrence, KS USA
Kleptoparasitic spiders primarily conduct foraging in the webs of larger spiders. The foraging strategies, e.g., araneophaging, scavenging, sharing prey with host, and silk eating, could be very flexible and interchangeable within a species. About 18 out of 220 species in Argyrodinae are group-living in the webs of their hosts. For these species, multiple individuals forage in one host web with strong conspecific tolerance, especially when sharing prey items directly with hosts. The function of this group-living behavior has never been tested. We aim to test if the group-living behavior of Argyrodes miniaceus could increase foraging efficiency when conducting the creep-up-and-share strategy. Argyrodes miniaceus and Nephila pilipes, were housed in lab in 2X2X2 feet cages. For each experimental trial, a ~0.3 g cricket was provided to the host spider. We used per capita feeding rate as the indicator of foraging efficiency and tested group sizes from 1 to 7 with replications ranging from 20 to 48 individuals in different group size treatments. The ANOVA result shows foraging efficiency is highest when two or three individuals are in a group and individuals in these group sizes are more likely to reach the prey. The time series analyses show when group size larger than four, A. miniaceus individuals take turns to feed and keep around two to three kleptoparasites at hub across the majority duration of each trail. Several behaviors were observed that associate with higher foraging efficiency in groups. We conclude that group-living behavior in A. miniaceus has the function of cooperation.
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Retreat construction by Clubiona riparia: reality vs. presumption
Robert B Suter	Vassar College Biology Poughkeepsie, New York USA
Female Clubiona riparia (Araneae: Clubionidae) build three-sided retreats in which they enclose both themselves and their eggs. A retreat is constructed by bending a single plant leaf twice, each time causing a fold that is roughly perpendicular to the long axis of the leaf, and joining the edges with silk. To assess the energetic costs involved in assembling a retreat (presuming that the actual method of construction could be ignored), I measured the work that had to be expended in bending and sealing the leaves of a grass, a cattail, an iris, and a willow, all leaves that are normally used by the spiders in retreat construction. The calculated costs of construction (excluding silk expenditure) were very small, the equivalent of about 0.05% of the energy content of single egg of C. riparia. Reality intruded, however, in the form of data on the actual behaviors used by these spiders in retreat construction: to bend the leaves, the female makes hundreds to thousands of excursions, shuttling between leaf edges that will ultimately be sealed together. Because of the large number of excursions, most of which have a vertical component and thus involve work against gravity, the work of moving the gravid spider herself is far more extensive than the work done against leaf stiffness. For the construction of a retreat on an Iris blade, for example, the spider must expend roughly 15 times more energy in overcoming gravity than it does in overcoming the blade’s resistance to being deformed.
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The role of acoustic and seismic communication in Gladicosa gulosa: complex vibration signals in a wolf spider.
Alexander L Sweger	University of Cincinnati Biological Sciences Cincinnati, OH USA
George W Uetz	University of Cincinnati Biological Sciences Cincinnati, OH USA
Many wolf spiders produce complex multimodal signals, making them excellent models for testing hypotheses about the evolution of signaling behavior. This research examines acoustic/vibratory communication in the “purring” wolf spider Gladicosa gulosa (Walckenaer, 1837). Only minimal research has been conducted on G. gulosa, but early studies describe the loud volume of its acoustic/vibratory courtship. This suggests that signaling in this species may be energetically costly, as well as vulnerable to eavesdropping by conspecifics and/or predators. Our objectives were to characterize the signals of courting male G. gulosa, and examine various components of courtship as a basis for future studies. Using Laser Doppler Vibrometry and sensitive microphones, we recorded and characterized the components of male courtship. Preliminary analyses suggest that courtship displays by males of this species produce both airborne (acoustic) and seismic (vibration) signals, and incorporate both stridulation and percussion. The components of courtship signals may be affected differently by male size or varying ecological conditions, including the type of substrate utilized for signaling. These results suggest the potential for eavesdropping, and male competitive behavior in the form of social facilitation of courtship.
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Behavioral evidence of pheromonal signaling in desert grassland scorpions
Matthew S Taylor	University of Oklahoma Department of Zoology Norman, Oklahoma USA
Douglas D Gaffin	University of Oklahoma Department of Zoology Norman, Oklahoma USA
Caleb R Cosper	University of Oklahoma Department of Zoology Norman, Oklahoma USA
Behavioral evidence suggests that, in some scorpion species, females deposit a pheromone that attracts mates, but no pheromone has been identified. The goal of our study was to isolate a pheromone from female desert grassland scorpions (Paruroctonus utahensis). We made in situ whole-body extracts of female P. utahensis in a chloroform-methanol solution; the extract stratified into aqueous and organic layers. In controlled laboratory experiments, most males exposed to female extract (aqueous and organic fractions combined) exhibited pre-courtship behavior, whereas those exposed to a control solution of chloroform-methanol showed no change in behavior. When the two extract fractions were separately tested, males initiated pre-courtship behavior when exposed to the organic fraction but not when exposed to the aqueous fraction. These data are the first experimental evidence of a female pheromone in this species and mark the first steps toward chemically characterizing a pheromone in any scorpion species.
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The role of visual cues in species and sex recognition in the jumping spider Lyssomanes viridis
Cynthia A Tedore	Duke University Biology Durham, NC USA
Sonke Johnsen
Few visually-apparent features, when viewed in isolation, are unique to any one species of terrestrial arthropod, even in sympatry. Misidentifying and displaying at the wrong species or sex of arthropod predator is dangerous. Thus, in taxa that identify conspecifics visually, selection should favor individuals capable of analyzing multiple features holistically. We tested the specificity of species and sex recognition in the jumping spider Lyssomanes viridis by presenting mature males with various images in the presence of female silk. Spider images having a conspecific face and/or legs elicited the expected threat and courtship displays. When a male face was combined with female legs and vice versa, roughly half of males courted and half threatened. Significantly fewer males displayed at a spider image that completely lacked the conspecific color pattern but had conspecific-shaped legs. Most males courted a female Thiodina sylvana image and were split between threatening and courting a male Hentzia palmarum image. Males did not display at a black circle. Results suggest males can assess multiple isolated features, but do not synthesize and evaluate features holistically, at least not in the presence of female silk.
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Food abundance, group foraging and territorial interaction in the California orb weaving spider Metepeira spinipes
Mark L Tiemeier	University of Cincinnati Biological Sciences Cincinnati, OH USA
George W Uetz	University of Cincinnati Biological Sciences Cincinnati, OH USA
Spiders tend to be solitary and aggressive, thus species which exhibit social behaviors offer opportunities to explore the evolution of sociality. Metepeira spinipes is a facultatively colonial orb-weaver from Mexico and California, and occurs in groups as well as solitarily, depending on environmental conditions. It appears to exhibit risk-sensitivity, as colonial foraging reduces variance in the amount of prey captured and the frequency and size of colonies is correlated with food availability. However, colonial aggregation is likely the consequence of both individual foraging decisions and specific interactions between spiders. In field experiments, we manipulated the food intake of spiders and found that well fed individuals (ad lib feeding) are significantly more likely to join a nearby colony than starved spiders. Additionally, we examined the interactions between spiders residing within colonies and diet-manipulated spiders which we added to their webs, and found that size rather than condition is the major factor influencing whether intruding spiders escalate encounters and overtake webs. The role of these factors in colony formation will be discussed.
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The goblin spiders (Oonopidae) of Madagascar: a morphological comparison of three genera.
Darrell Ubick	California Academy of Sciences Entomology San Francisco, CA
Charles Griswold	California Academy of Sciences Entomology San Francisco, CA
Madagascar has a rich oonopid fauna of over 100 species representing about 24 genera. Most of the species and about 60% of the genera are new and apparently endemic to the island. Here we report on three of these endemic genera. Genus 1 includes species with large contiguous eyes (eye ring), prominent leg spines, reduced scutes in females and fused scutes in males, all characteristic of the Ischnothyreus complex. Genitalic characters of both the male and female suggest a close relationship to the Asian genus Camptoscaphiella. Genus 2 resembles the many Malagasy species of the Silhouettella complex in several somatic characters, such as body form, eye arrangement, body sculpturing and leg spination, but differs in genitalic features. The male embolar region has few broad lobes, as opposed to several slender lobes in silhouettelloids, and the female genitalia lack a large oval receptaculum characteristic of silhouettelloids. Apart from that difference, the female genitalia are typically silhouettelloid and suggest that the genus belongs in this complex. Genus 3 includes small spiders with reduced eyes and scutes, and with an unusual character combination. The genus resembles silhouettelloids in body form, leg spination and eye arrangement, but also ischnothyroids in that males have fused abdominal scutes. The female genitalia likewise include characteristics of both groups. The placement of this genus is speculated but remains unresolved.
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Chemical communication in Schizocosa ocreata (Hentz): a reassessment.
George W Uetz	University of Cincinnati Biological Sciences Cincinnati, OH USA
Andrea Orton
Trisha Myers
Andrew Roberts	The Ohio State University Evolution Ecology and Organismal Biology Newark, OH USA
Chemical communication is an important part of the mating process in the wolf spider Schizocosa ocreata (Hentz 1844), as cues associated with female silk are sufficient to elicit courtship from males. However, several questions arise about the role of chemical cues and the nature of chemical communication, which have not been studied in depth. We examined how both male and female S. ocreata wolf spiders respond to silk-borne, airborne and cuticular hydrocarbon (CHC) cues from members of either sex. Not surprisingly, males spent significantly more time on female silk. Females spent significantly less time on female silk. However, there were no significant differences for either sex between time on male silk vs. a control (filter paper, no silk). Males and females showed no significant directional response to airborne (olfactory) chemical cues from either sex, but males displayed courtship behaviors more often and at higher rates in the presence of airborne cues from females. Males responded with courtship to filter paper impregnated with cuticular hydrocarbon (CHC) cues of adult females, as well as female exuviae. Comparison of rates of male courtship behaviors exhibited in response to chemical cues from females suggest that silk-borne and CHC cues elicit higher rates of male signaling than airborne cues, but the latter may stimulate courtship at a distance. These data suggest that chemical communication in this species is unidirectional and female-originated, but more complex than previously believed, as multiple sources of chemical cues may be involved in stimulating male courtship.
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Scavenging behavior in spiders
Richard S Vetter
Historically, spiders are considered to be obligatory predators of live, animate prey. A 2003 study promoted the notion that brown recluse spiders preferentially scavenged rather than attack live prey. In contrast, a 2005 study showed that brown recluse scavenging rate was only 10% to 42% when spider satiation, prey size and prey age was manipulated. The 2003 study also proffered that brown recluse scavenging was due to high intraspecific competition in homes. Spider scavenging is not well documented in the literature. Is scavenging a rare behavior exhibited by brown recluses and possibly a few other species? This study addressed spider scavenging in general. Freeze-killed crickets were offered to 100 non-Loxosceles spiders (11 families, 24 genera, 29 species) from a variety of spider hunting guilds. Also included were web-spinners that can secure prey dorsum up (i.e., Agelenidae, Filistatidae, Amphinectidae but not Theridiidae, Araneidae, Pholcidae); webspinners should almost never have the chance to scavenge in nature. Crickets were also offered to 20 brown recluse spiders. Spiders were offered dead crickets at one-week intervals for three consecutive weeks; this compensated for satiation due to pre-trial feeding and pre-molt feeding cessation. Of the 100 non-Loxosceles spiders, 99 scavenged dead crickets, 89 in the first trial. All 20 brown recluses scavenged. Therefore, scavenging in spiders is not rare, just rarely studied. Given the opportunity, many families of spiders exhibit scavenging; it is not a special behavior expressed by the brown recluse. However, the extent to which scavenging occurs in nature is still debatable.
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A Brief History of the Beginning of The American Arachnological Society
Beatrice R Vogel
In 1968 the first issue of the newsletter American Arachnology was published. In 1972 the organizational meeting of the American Arachnological Society was held in Rustler's Park campground in the Chiracahua National Forest. In 1975 the 4th annual meeting and first international meeting of AAS was held at Warrensburg Missouri.
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SPIDA: Using expert systems on the web to identify spiders:
James D Wagner	Transylvania University Biology Lexington, KY
Justin Blackburn
Mike McNary
For all researchers who study spiders and their kin it becomes our contractual obligation to identify spiders for homeowners in our community. Frequently we are forced to make these identifications, sight unseen, based solely on narrative descriptions offered by the apprehensive layperson. Over the years I have been interested in using a web-based computer program and the internet to simulate the thought processes we use when making identifications not by sight but by narrative description. In this identification process we frequently ask questions concerning the behavior or ecology of the spider in addition to physical descriptions of the spider. As we collect these answers, we assign them relative weights and rank them in terms of their strength of correlative association and predictive value. For example, being told the spider could climb on the vertical glass window may be more informative than being told the spider is brown. Ultimately our identification is based upon the associated suite of traits (morphological, behavioral, ecological) given. Computer software engineers have attempted to mimic this process by developing Expert System software. Using these systems as a model, we developed SPIDA an internet based interactive key designed to identify spiders common around, and in, buildings in Kentucky. SPIDA avoids using technical terms or dichotomous keys to identify spiders, but instead simulates the types of questions arachnologist use to make best guess identifications without actually seeing the specimen.
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The effect of reproductive status on the predatory efficiency of female Arizona Bark Scorpions (Centruroides sculpturatus)
Michael M Webber	University of Nevada Las Vegas Life Sciences Las Vegas, NV USA
Javier A Rodriguez-Robles
Acquiring resources is crucial for an organism’s survival, and therefore animals spend a considerable amount of time foraging for food. Studies have shown that the foraging and feeding rates of predators can be influenced by their reproductive state. Changes in the feeding rates of female predators during pregnancy can influence maternal energy reserves, as well as the amount of resources allocated to offspring development during gestation. Although changes in the feeding rates of gravid (pregnant) female predators have been documented, the efficiency with which gravid females capture prey has received much less attention. We investigated how predatory efficiency may be influenced by reproductive state in female Arizona Bark Scorpions (Centruroides sculpturatus). Prey-handling trials were conducted, and the times taken to pursue and subdue prey were compared among females of different reproductive states. Our results suggest that gravid females do not experience decreases in predatory efficiency, suggesting that they are able to mechanically cope with increases in body mass and physiologically handle the metabolic cost of developing offspring during gestation. Further, prey-handling times increased significantly for females exhibiting maternal care (carrying offspring on their backs) compared to non-reproductive and gravid females. Following offspring dispersal, females did not exhibit faster prey-handling times than females still carrying offspring possibly due to physiological exhaustion following maternal care. These results suggest that the cost of reproduction in terms of reduced prey-handling efficiency for female Arizona Bark Scorpions is experienced during and subsequent to the maternal care period.
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The behavioral mechanisms of site selection by web-building spiders
Kelton D Welch	University of Kentucky Department of Entomology Lexington, KY USA
Kenneth F Haynes
James D Harwood	University of Kentucky Department of Entomology Lexington, KY USA
The placement of spider webs is an excellent model system for the study of habitat utilization by animals. Patterns of site utilization have been found to correlate with the availability of potential prey and with the distribution of suitable support structures. However, the behavioral mechanisms driving the foraging-site selection by spiders are not fully understood. Previous research suggests that web-building spiders respond directly to habitat structures, which can serve as indirect indicators of prey availability, and that spiders only monitor direct cues from the prey after web construction, to evaluate the profitability of the site and to decide whether or not to remain in it. The role of prey cues in the initial selection of foraging sites by web-building spiders has received very little attention. In this study, a combination of field and laboratory techniques was used to determine how web-building spiders select and utilize foraging sites. In field collections, we uncovered interspecific differences in habitat structure utilization that correlated with differences in activity density of a major prey group, Collembola, supporting the hypothesis that habitat structures indirectly indicate prey availability. However, two-choice experiments were run in laboratory arenas, giving spiders a choice between structurally identical sites with and without prey. In these experiments, spiders showed significant preference for the site with prey. These data combined indicate that both structural and prey cues are involved in the initial selection of foraging sites by web-building spiders. The implications of these findings for spider trophic ecology and biological control potential are discussed.
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Advancing molecular systematics of spiders (Araneae) with expressed sequence tags and gene tree parsimony
Michael H White	Washington and Lee University Biology Lexington, VA USA
Jessica E Garb	University of Massachusetts Lowell Biological Sciences Lowell, MA
Cheryl Y Hayashi	University of California Riverside Biology Riverside, CA USA
Nadia A Ayoub	Washington and Lee University Biology Lexington, VA USA
Spiders (Araneae) belong to one of the most diverse orders of animals, comprising 110 recognized families, 3821 genera, and 42,055 species. Much of this diversity is likely ancient, with fossils representing modern families dating to well over 100 million years ago. Thus, identifying shared derived characters and determining the evolutionary relationships among families has been challenging for both morphological and molecular systematists. Molecular systematics of spiders has additionally been hampered by limited genetic information. However, there is a growing database for numerous species of short sequences (less than 800 base pairs) that represent portions of expressed genes (expressed sequence tags, ESTs). We compiled ESTs for 35 species, representing 26 families, by combining publically available sequences with our own database of genes expressed in silk glands. We assembled ESTs for each species separately to create non-redundant sets of contiguous sequences (contigs), resulting in a total of 16,141 contigs. Basic Local Alignment Search Tool (BLAST) identified all potential homologs among spider contigs. We wrote a complex clustering algorithm in Python to construct non-overlapping groups of homologous ESTs. Clusters typically contained both orthologs and paralogs. We then performed global alignments and determined maximum parsimony gene trees for each cluster individually. We will use gene tree parsimony to infer a species tree that minimizes the number of gene duplication events across the final set of maximum parsimony gene trees.
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Diel periodicity in activity and location in the web of the common house spider (Achaearanea tepidariorum)
Elise M Wolf	East Tennessee State University Biological Sciences Johnson City, TN
Thomas C Jones	East Tennessee State University Biological Sciences Johnson City, TN
Darrell J Moore
Circadian rhythm is a type of endogenous clock that controls daily behavioral patterns in most organisms. Spiders have been shown to exhibit both circadian and non-circadian rhythms in their behaviors. This rhythmicity may allow spiders to cope with diel changes in environmental conditions. Both diurnal and nocturnal behavior have different sets of costs and benefits to a species’ survival. Achaearanea tepidariorum is one species in which potential circadian rhythmicity has never been studied. Due to its foraging behavior, it was predicted that its daily activity would be arrhythmic. We recorded the positions within the web of forty individuals throughout the day, and then observed their daily activity via use of an infrared activity monitor. Analysis of the resulting actograms and web position data revealed a significant nocturnal periodicity in the spiders’ activity, as well as possible anticipation of the daily cycle. This nocturnal periodicity, coupled with specific web-building behavior, may be the result of this species balancing the costs and benefits of predation and foraging. More studies are needed to provide more information about the circadian behavioral patterns of A. tepidariorum.
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Archaeid spiders and their relatives (Araneae, Archaeidae): fossil placement, biogeography and evolution of the carapace morphology
Hannah M Wood	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
Rosemary G Gillespie	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
Charles Griswold	California Academy of Sciences Entomology San Francisco, CA
Molecular and morphological phylogenetic analyses are performed for living and extinct archaeids and for outgroup taxa representing 20 different spider families sampling throughout the Araneomorphae. Fossil archaeids are examined using X-ray Computed Tomography in order to understand phylogenetic placement of extinct lineages. Additionally, a molecular phylogenetic analysis of living archaeids is performed to elucidate relationships among extant species from Australia, Madagascar and South Africa. Biogeographic findings within different continents as well as between continents are discussed. The limits of the superfamily Palpimanoidea is examined. Furthermore, evolution of the carapace shape is examined from a phylogenetic context.
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Evolution of a complex, novel structure, the trap-jaw mechanism, in spiders (Mecysmaucheniidae, Araneae)
Hannah M Wood	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
Rosemary G Gillespie	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
Charles Griswold	California Academy of Sciences Entomology San Francisco, CA
Damian O Elias
Trap jaw mechanisms have been described for the ant genus Odontomachus but is virtually unknown in one of the largest arthropod classes, the arachnids. The trap jaw mechanism has evolved twice independently in spiders, once in the family Pararchaeidae and once in the family Mecysmaucheniidae. The underlying structural mechanism for employing a trap jaw is unique in both families, with Mecysmaucheniids achieving the fastest known movements in arachnids. Within the mecysmaucheniids there is variation in both carapace and jaw shape and in the speeds of the jaws closing. Phylogenetic analyses of molecular data results in a mecysmaucheniid phylogeny that can be used to examine the evolution of this trait among lineages from New Zealand and Chile as well as to examine how this trait relates to distribution patterns. The biomechanical properties of this complex trait are examined among different lineages.
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Does Hawaiian Tetragnatha venom composition vary with feeding strategy?
Andrew W Wood	Lewis & Clark College Biology Portland, OR USA
Rosemary G Gillespie	University of California Berkeley Environmental Science Policy and Management Berkeley, CA USA
Greta J Binford	Lewis Clark College Biology Portland, OR USA
Spider venoms are a rich source of largely unexplored biodiversity, and we have much to learn about the evolutionary mechanisms that generate this stunning diversity. The Hawaiian radiation of Tetraghatha offers a unique system with which to address this question. The majority of the 35 Hawaiian Tetragnatha species are orb-weaving spiders, however, a recently derived lineage has abandoned this ancestral state to adopt a cursorial feeding strategy, and have become obligate wanderers (Gillespie 1999). Binford (2001) demonstrates some differences between the venoms of these two species, but was unable to specifically identify venom components. In this study, I apply transcriptomic methods to 1) characterize the venom of two species of Hawaiian Tetragnatha (one orb-weaving and one wandering) and 2) analyze differences and similarities between them. After screening cDNA libraries for both species I identified a total of 5 distinct putative toxins including homologs of theraphotoxins and lycotoxins, none of which were common to both species. However, the vast majority of cDNAs that I identified were ribosomal or other ‘housekeeping’ sequences. This study demonstrates that after methodological optimization, the venom of Hawaiian Tetragnatha can be successfully characterized and will be useful to address questions regarding the evolution of chemical biodiversity.
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Microstructure of the Nerve Cell Clusters in the Wolf Spider Arctosa ngreungensis (Araneae: Lycosidae)
Sung-Chan Yang	Dankook University Biological Sciences Cheonan, Korea
Yong-Ki Park	Dankook University Biological Sciences Cheonan, Korea
Myung-Jin Moon	Dankook University Biological Sciences Cheonan, Korea
Research on the central nervous system (CNS) of arachnids is still an unexplored field compared to insects or crustaceans. Here, we have investigated the microstructure of the nerve cell clusters in the wandering spider, Arctosa kwangreungensis using various visualization techniques. For image processing and reconstruction, serially sectioned paraffin blocks were scanned with research complex microscopy, and 3D images were reconstructed from the brain sections. The image stacks of the central complex and surrounding neuropils obtained from the brain sections were processed using Amira 5.3.2 software. In A. kwangreungensis, the supraesophageal ganglion (brain) of an adult spider is made up of a protocerebral and tritocerebral ganglion, whereas the subesophageal ganglionic mass is composed of a single pair of pedipalpal ganglia, four pairs of appendage ganglia, and a fused mass of abdominal neuromeres. The only nerves arising from the protocerebrum are the optic nerves, and the neuropiles of the principal eyes are the most thick and abundant. In the supraesophageal ganglion. Complex neuropile masses are located in the protocerebrum including optic ganglia, the mushroom bodies and the central body.
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Magnetic Resonance Imaging and Spectroscopy of Spiders
Jeffery L Yarger	Arizona State University Chemistry Biochemistry and Physics Tempe, AZ
Brian R Cherry
Our group at Arizona State University is interested in how spiders produce silk with the goal of reproducing this process in the laboratory. Many of the secrets in silk production come from our lack of molecular level understanding of how silk proteins are produced, stored and secreted from glands, through ducts and out spinnerets. We are using magnetic resonance imaging (MRI) and spectroscopy (MRS) to better elucidate this process. We are able to obtain micro-MR images and spectra from live spiders and use this data to help us better understand protein structure and dynamics at the molecular level.
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Biochemical Investigation into the Presence of Golgi Apparatus in Spider Silk Glands
Robin Zafra
Merri L Casem	California State University Fullerton Biological Science Fullerton, CA USA
Spider silk is a large multi-protein polymer that is synthesized by cells that form silk producing glands in the abdomen of the spider. One would predict that silk, like all secretory proteins would be synthesized on the rough endoplasmic reticulum (rER), processed by the Golgi apparatus and secreted from cells into the lumen of the glands. Interestingly, the Golgi apparatus is not apparent in transmission electron micrographs of silk-producing cells. A biochemical assay was conducted to detect the presence of the Golgi in tissues of the black widow spider, Latrodectus hesperus, using a glycoprotein western detection kit. I combined glycoprotein detection with an assay for EndoH sensitivity to determine whether glycoproteins present in the spider’s tissues have been modified by the Golgi apparatus; causing them to become EndoH resistant. Results indicate that the glycoproteins are EndoH sensitive, supporting the idea that the proteins only go through core glycosylation in the rER and do not enter the Golgi apparatus.
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Intersexual coevolution of genitalia in euophryine jumping spiders (Araneae: Salticidae): sexual selection or “lock-and-key”?
Junxia Zhang	University of British Columbia Zoology Vancouver, BC Canada
Wayne P Maddison	University of British Columbia Zoology Vancouver, BC Canada
A long-standing question in spider evolution is the extent to which genitalia are sexually selected or serve as species recognition mechanism (“lock-and-key”). We investigated the lengths of the male embolus and female copulatory duct of euophryine jumping spiders, and found they are positively correlated among species. This correlation confirms an interaction, but it does not indicate the selective mechanism involved. Intra-specific variation of these traits in ‘Sidusa’ recondita and ‘Cobanus’ cambridgei shows negative allometry. While this may appear to favor the “lock-and-key” scenario, it could also occur via post-copulatory sexual selection. The size-corrected intra-specific variation is high for genitalia, which has been argued to indicate sexual selection, but could also arise through developmental mechanisms to achieve negative allometry. However, if high intra-specific variation is indicative of sexual selection, there remains the question of the mechanism: cryptic female choice or sexual antagonistic coevolution. An antagonistic arms race of ever-increasing embolus and CD length can be rejected, as decreases appear to occur as often as increases on the phylogeny. Unlike the genitalic traits, the pre-copulatory sexually-selected traits (male chelicerae) tend to show positive intra-specific allometry, and thus may have evolved under strong directional selection. The fact that the species with stronger somatic sexual dimorphism (‘Cobanus’ cambridgei) has the lower intra-specific variation in genitalia may imply a trade-off between pre- and post-copulatory sexual selection. The mechanisms underlying the variability of euophryine genitalia remain unclear, and in fact sexual selection and species isolation mechanisms in principle could coexist.
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Chromosome mapping of dragline silk genes in the genomes of widow spiders (Araneae, Theridiidae)
Yonghui Zhao	University of California Riverside Biology Riverside, CA USA
Nadia A Ayoub	Washington and Lee University Biology Lexington, VA USA
Cheryl Y Hayashi	University of California Riverside Biology Riverside, CA USA
Western black widow (Latrodectus hesperus) and brown widow (L. geometricus) spiders are in the cob-web weaver family, Theridiidae (Araneae). We determined karyotypes and sex chromosome organization for these two species. We then used fluorescent in situ hybridization to map the genomic locations of the genes for the silk proteins that compose the remarkable spider dragline. These genes included three loci for the MaSp1 protein and a single locus for the MaSp2 protein. In addition, we mapped a MaSp1 pseudogene. All the MaSp1 gene copies and pseudogene localized to a single region of chromosome 1 while MaSp2 was located on chromosome 8 in L. hesperus. Using probes derived from L. hesperus, we comparatively mapped all three MaSp1 loci to a single region of chromosome 4 in L. geometricus. As with L. hesperus, MaSp2 was found on a separate L. geometricus chromosome, chromosome 2. These results indicate orthology of the corresponding chromosomal regions in the two widow genomes. Moreover, the occurrence of multiple MaSp1 loci in a conserved gene cluster across species suggests that MaSp1 proliferated by tandem duplication in a common ancestor of L. geometricus and L. hesperus.
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Accumulation of toxic heavy metals in urban spider webs
Liza Zimmerman	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Amneh Awad
Anne Danielson-Francois	University of Michigan Dearborn Biology Discipline Natural Sciences Dept Dearborn, MI USA
Spiders in urban environments are impacted by many variables: the quality of the habitat, type of prey available, and urban pollution from anthropogenic sources. Although some urban ecological studies have focused on insects, such as ants, no studies have focused on a key arthropod predator: spiders. Spiders may be especially affected by poor air quality in ways that insects are not because spiders build webs that may act as environmental filters. In urban environments air quality may be poor, particularly near industrial sites. Spiders that build webs may be especially affected by air pollution in the form of ultra-fine particles (such as are released from motor vehicles and also some industries) that are caught and contained in their webs. We sampled spider webs from an urban neighborhood in Detroit near an industrial area by the Detroit River for three consecutive weeks in July 2009 and July 2010. We found that detectable levels of toxic heavy metals were trapped in spider webs. This result could help to make direct connections between humans and their effects on the environment, as well as bringing to light some potential health hazards in urban settings for people as well as spiders.
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The Phylogenetic Scale of Venom Variation in Sicariid Spiders
Pamela A Zobel-Thropp
Miles M Dale	Lewis & Clark College Biology Portland, OR USA
Greta J Binford	Lewis Clark College Biology Portland, OR USA
The spider family Sicariidae includes two genera, Loxosceles (including the brown recluse) and Sicarius (6-eyed sand spiders). Members of this family has been evolving for over 100 million years in the context of being generalist, ground-dwelling predators of arthropods. They are best known for the ability of their venoms to cause dermonecrotic lesions in mammals, an effect that is caused by the toxic venom enzyme sphingomyelinase D. We are characterizing the venomes of a broad phylogenetic representation of species in the sicariid family. With these comparative data we are analyzing the evolution of the full venom cocktail in a lineage with remarkably little evident evolutionary change in feeding biology. We will discuss patterns of presence and absence of multiple venom toxin lineages evolving within this group, and patterns of positive selection within select toxin lineages. Together these data help illuminate the evolutionary dynamics that have shaped venom diversity.
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