New Paper: Microgeographic evolution of metabolic physiology in a salamander metapopulation

Emerging evidence for adaptive microevolution of metabolic physiology led us to hypothesize that metabolic rate might exhibit evolved variation on microgeographic scales. To evaluate our hypothesis, we explored evidence for evolved variation metabolic rate within a spotted salamander (Ambystoma maculatum) metapopulation in Connecticut, USA. Using common-garden raised spotted salamanders from 22 different populations we tested for the effects of six ecological variables suspected in advance to select for divergent physiology. We found evidence for interpopulation variation in metabolic rate best explained by differences in population density among ponds. Our results illustrate how fundamental physiological processes such as metabolic rate can evolve across microgeographic spatial scales.