Meeting Abstract
Social and environmental factors influence the behavioral decisions of all animals. Behavioral choices require time and energy investment, and tradeoffs occur when critical behaviors must be performed in specific habitats. Ectotherms in thermally stressful environments reduce stress by altering microhabitat use, yet behavioral thermoregulation using shade or burrows can lead to missed opportunities if functions like reproduction must occur in stressful areas. Fiddler crabs mate in high intertidal areas, where males perform a claw-waving display. Courting behavior is limited by heat and desiccation stress, which is ameliorated by retreat into cool moist burrows. Yet this burrow retreat requires a cessation of mating behavior and thus a potential fitness cost. We examined impacts of thermal-hydric stress on surface activity and waving behavior in the fiddler crab Uca pugilator, an abundant sandy-shoreline species extending from Massachusetts to the Bahamas. The present study focuses on three sites along the species latitudinal-thermal range: Panacea, FL (30.0159°N), Beaufort, NC (34.7115°N), and Stony Brook, NY (40.9357°N), allowing for the examination of the trade-off between thermal-hydric stress and mating success under different thermal regimes. Operative body temperatures were quantified using physical models and compared to preferred temperatures to assess thermal habitat quality at each site. Simultaneously, body temperatures and hydration states of surface-active males in the high-intertidal breeding area were measured. In order to evaluate the impact of thermal-hydric stress on surface activity and waving behavior, video footage was used to quantify activity budgets (including time on the surface and time in the burrow) across a range of thermal conditions.
