Behaviour 2019
Impacts of Biotic and Abiotic Factors on the Duration of Surface Activity and Burrow Retreats in Minuca pugnax
Jacquline Rich1, Sarah Hews2, Adrienne Baxter1, Zahida Sheikh1, Jenny Wu1, Heidi Zakoul1, Renae Brodie1. 1Mount Holyoke College, South Hadley, MA, United States; 2Amherst College , Amherst, MA, United States

The fiddler crab Minuca pugnax is an intertidal ectotherm that navigates an environmentally variable habitat and uses burrows for behavioral thermoregulation. The stable, cool temperatures of burrows offer an effective means of thermoregulation on hot days. We examined the impacts of surface and burrow temperatures, density of conspecifics, tidal height, and individual behaviors on the duration of surface activity and burrow retreats in surface-active males. We found that the duration of surface activity was impacted by changes in surface temperature, burrow temperature, and density of conspecifics. As surface temperature decreased and density of conspecifics increased, the duration of surface activity increased. However, surface density and temperature were correlated, making the impact of these variables on surface activity impossible to disentangle in this study. The average duration of burrow retreat was short and consistent and not impacted by any environmental variable, suggesting that crabs cool rapidly in burrows. These data show that the duration of surface activity is impacted by environmental variables while the duration of burrow retreat is not.