Combinations of reproductive, individual, and weather effects explain torpor patterns among female little brown bats (Myotis lucifugus)

Abstract

Torpor is a thermoregulatory strategy used by some small mammals to, in part, conserve energy during poor weather conditions and limited food. Some mammalian females may use torpor throughout reproduction, however, there are associated physiological and ecological costs and benefits. Torpor use may vary among individuals and result in different fitness consequences. The objective of my study was to identify and quantify variables that best explain variation in torpor patterns among individual female little brown bats (Myotis lucifugus). I used an information-theoretic approach to rank Bayesian models containing reproductive condition, individual, and weather variables based on their probability of explaining variation in torpor. Precipitation and wind were the most influential predictors of torpor frequency, whereas reproductive condition and individual were the best predictors of torpor duration, depth, and the heterothermy index. These results highlight the importance of including multiple intrinsic and extrinsic variables when evaluating thermoregulatory patterns.