Meeting Abstract
Small-scale shifts in species distributions are expected to occur under future climate scenarios for many species. These shifts can have consequences for population dynamics, and therefore it is important to understand when and why they occur. The intertidal crab Petrolisthes cinctipes currently experiences temperatures near lethal levels. However, the extent to which crabs move in response to temperature and the thermal thresholds that trigger migration to cooler microhabitats remain unknown. We tested for effects of body size and reproductive state on escape temperature (Tesc). In addition, we tested for the relationship between Tesc and the temperature of peak action potential firing frequency in sensory afferent neurons. We found that both size and reproductive state influence behavioral sensitivity to temperature. Small crabs tolerate significantly higher temperatures before they move to cool refuges (a higher Tesc) compared to large crabs. In addition, non-gravid crabs have significantly higher Tesc than gravid females. We also found that Tesc is positively correlated with peak neural performance of spontaneous action potentials (R2″“=0.26). We find that behavioral sensitivity to temperature varies consistently with size and reproductive state. These findings have implications for species persistence, rates of dispersal and community dynamics. The vulnerability of marine organisms to global change is predicated on their ability to utilize and integrate these physiological and behavioral strategies to promote survival and reproductive fitness; understanding these strategies will allow predictions of species distributions under warming and the potential for extirpation.
