Does behavioral thermal tolerance predict distribution pattern and habitat use in two sympatric Neotropical frogs?

Environmental temperatures are a major constraint on ectotherm abundance, influencing their distribution and natural history. Comparing thermal tolerances with environmental temperatures is a simple way to estimate thermal constraints on species distributions. We investigate the potential effects of behavioral thermal tolerance (i. e. Voluntary Thermal Maximum, VT Max ) on anuran local (habitat) and regional distribution patterns and associated behavioral responses. We tested for differences in Voluntary Thermal Maximum (VT Max ) of two sympatric frog species of the genus Physalaemus in the Cerrado. We mapped the difference between VT Max and maximum daily temperature (VT Max —ET Max ) and compared the abundance in open and non-open habitats for both species. Physalaemus nattereri had a significantly higher VT Max than P . cuvieri . For P . nattereri , the model including only period of day was chosen as the best to explain variation in the VT Max while for P . cuvieri , the null model was the best model. At the regional scale, VTMax—ET Max values were significantly different between species, with P . nattereri mostly found in localities with maximum temperatures below its VT Max and P . cuvieri showing the reverse pattern. Regarding habitat use, P . cuvieri was in general more abundant in open than in non-open habitats, whereas P . nattereri was similarly abundant in these habitats. This difference seems to reflect their distribution patterns: P . cuvieri is more abundant in open and warmer habitats and occurs mostly in warmer areas in relation to its VT Max , whereas P . nattereri tends to be abundant in both open and non-open (and cooler) areas and occurs mostly in cooler areas regarding its VT Max . Our study indicates that differences in behavioral thermal tolerance may be important in shaping local and regional distribution patterns. Furthermore, small-scale habitat use might reveal a link between behavioral thermal tolerance and natural history strategies.