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Cara Shillington
Faculty
Eastern Michigan University
Biology
Ypsilanti, MI
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| Effects of Food Limitation on Locomotory Behavior in Tarantulas (Brachypelma albopilosum) |
| Author(s) |
Michael H Kaminski, Cara Shillington |
| Info |
Poster category:
Behavior |
| Abstract |
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. |
| Activity of male tarantulas (Brachypelma vagans) during the mating season |
| Author(s) |
Cara Shillington |
| Info |
Talk category:
Behavior |
| Abstract |
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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