Latitudinal variation in body size in Fejervarya limnocharis supports the inverse of Bergmann’s rule: Supplementary Material

Bergmann’s rule states that within a species of endotherms smaller individuals are found in warmer conditions, which is consistent for nearly all endotherms, while in ectotherms body size patterns are less consistent. As ectothermic vertebrates, the morphology of amphibians is likely impacted by climatic conditions. Here, we examined latitudinal variation in body size in the ranid frog, <i>Fejervarya limnocharis</i>, based on literature and our own data on mean body size of 3637 individuals from 50 populations and average age of 2873 individuals from 40 populations in China. The results showed that body size was positively correlated with environmental temperature, but not with precipitation. Body size was negatively correlated with latitude among populations in this species, which supported the inverse of Bergmann’s rule. Our findings suggest that a larger body size in low-latitude populations is associated with a longer growing season related to the higher environmental temperatur

Brain size in Hylarana guentheri seems unaffected by variation in temperature and growth season. Supplementary Table S1

<p>Brain size varies dramatically between vertebrate species. Two prominent adaptive hypotheses – the Cognitive Buffer Hypothesis (CBH) and the Expensive Brain Hypothesis (EBH) – have been proposed to explain brain size evolution. The CBH assumes that brain size should increase with seasonality, as the cognitive benefits of a larger brain should help overcoming periods of food scarcity via, for example, increased behavioral flexibility. Alternatively, the EBH states that brain size should decrease with seasonality because a smaller brain confers energetic benefits in periods of food scarcity. Here, to test the two adaptive hypotheses by studying the effects of variation in temperature and growth season on variations in overall brain size and the size of specific brain regions (<i>viz</i>. olfactory nerves, olfactory bulbs, telencephalon, optic tectum and cerebellum) among <i>Hylarana guentheri </i>populations. Inconsistent with the predictions of both the EBH and the CBH, variation in temperature and growth season did not exhibit correlations with overall brain size and the size of brain regions across populations. Hence, our data do not provide support for either the EBH or the CBH to explain brain size variation in <i>H. guentheri</i>. Furthermore, brain size variation did not differ between males and females in this species. Our findings suggest that both the variation in temperature and growth season did not shape the variation in brain size in <i>H. guentheri</i>. </p