Ecological energetics of small, wild mammals: from flexibility of fitness

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For a half-century, comparative physiologists have used comparisons of species to understand causes of variation in traits affecting energy balance of endotherms (i.e., mammals and birds). Often, these comparisons have addressed maintenance or basal metabolic rate (BMR), a trait thought to be of importance because of significant direct or indirect consequences for reproductive fitness. More recently, evolutionary physiology has recognized the importance of studying variation within, as well as between species and this approach has been applied with particular success to the study of mammalian hibernation. Evolutionary physiologists have also begun to address the potential evolutionary and ecological importance of correlations between metabolism, life history traits and behavioural syndromes or animal personalities based, in part, on the prediction that, within species, "low energy" behavioural and life history traits should correspond with "low energy" metabolic rates. Within this context, I aim to: 1) identify factors which explain intraspecific variation in torpor expression by hibernators; 2) test hypotheses about links between personalities, life histories and energetics; 3) begin to quantify the importance to hibernators of phenotypic plasticity in physiological and behavioural traits; and 4) begin to link these sources of phenotypic variation to variation in survival and fitness in wild populations. My students and I will employ observational field studies and experimental laboratory work on bats and ground squirrels, and use long-term datasets to connect intraspecific variation in energetic and behavioural traits with survival and fitness in the wild. This work has fundamental significance for understanding mammalian evolution and ecology, as well as applied significance for understanding how species and populations might respond to environmental change. Our work on hibernation in bats is also important for understanding and addressing White-Nose Syndrome, a fungal pathogen which has caused starvation of over a million hibernating bats in the northeastern U.S. since its discovery in 2006.