Meeting Abstract
Increased frequency of severe high temperatures is expected to increase with global climate change, and as a result shifts in species distributions are expected to intensify. Characterizing the temperatures at which animals will move is therefore an important element of predicting the consequences of ongoing warming. For example, thermal microhabitats of the intertidal zone porcelain crab, Petrolisthes cinctipes, can reach lethal levels, but at what temperature the crabs migrate to cooler locations is unknown. The thermal preference of this species is indicative of their optimal temperature range and the set-point at which crabs exhibit avoidance behavior will, thus, inform ecological predictions regarding emigration. Thermoregulatory behavior was examined by placing crabs in an aquatic thermal gradient and recording water temperature at the location of the crab over time. Thermal avoidance behavior was measured as the temperature at which crabs exited a temperature chamber during a thermal ramp. We hypothesized that characteristics such as sex and size will influence thermal preference and avoidance behaviors. The mean preferred temperature was 15.1°C ± 1.7. During thermal ramps, where temperature increased at a rate of 1.1°C/min, crabs exhibited avoidance behavior at a mean temperature of 23.5°C ± 5.3. In the field we have observed habitat temperatures that exceed these thresholds. We saw no significant difference in sex or size in either experiment. Ultimately, these data will provide insight to how future temperatures may cause migratory behavior away from microhabitats that are no longer within a physiologically permissive range. Such movement may have consequences for increased intra- and interspecific interactions that can cause cellular stress and potentially reduce fitness.
