Influence of seasonality and sex on the behavioral thermoregulation of the crab Neohelice granulata

Behavioral thermoregulation is a strategy often used by many ectotherms to deal with the increase in ambient temperature. Animals that live in the intertidal zone can emerge from the water to cool their body temperature in the aerial environment. The objective of this work was verify if thermoregulatory behavior of the crab Neohelice granulata is influenced by seasonality and sex, and if it is correlated with preferred temperatures.We also check if this emerging behavior is correlated with the crab's preferred temperature. Males and females of N. granulata were recorded for one hour in two different experiments for two periods (autumn/winter and summer). In the first experiment, we observed the behavior of crabs that were allowed to freely move within an open arena that was divided into aerial and aquatic areas in which the air temperature was close to the water temperature (20°C, 23°C, 26°C, 29°C). Animals collected in winter and summer increased the time spent in emersion proportionally to the increase in temperature. In the second experiment, we submitted the crabs to a horizontal temperature gradient divided into three zones (cold (16–23°C), intermediate (24–26°C), and hot (27–30°C)), in which the crabs maintained submerged, then we evaluated their preferred zone. Surprisingly, females and males collected in summer preferred lower temperatures than those collected in winter. Therefore, seasonality influences the behavioral profile of thermoregulation of N. granulata, but both males and females collected in winter and summer presented the same behavioral profile. [Display omitted] •Summer crabs prefer lower temperatures than winter crabs.•Crabs in higher temperatures spent longer times emerged than controls.•Winter animals stayed emerged longer time than summer animals.