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Matthew S Taylor
Other: Research Associate
University of Oklahoma
Department of Zoology
Norman, Oklahoma USA
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| Scorpion fluorescence and reaction to light |
| Author(s) |
Douglas D Gaffin, Lloyd A Bumm, Nataliya V Popokina, Matthew S Taylor, Shivani Mann |
| Info |
Poster category:
Behavior |
| Abstract |
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. |
| Behavioral evidence of pheromonal signaling in desert grassland scorpions |
| Author(s) |
Matthew S Taylor, Douglas D Gaffin, Caleb R Cosper |
| Info |
Talk category:
Behavior |
| Abstract |
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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