Meeting Abstract
Accumulating evidence suggests that behavioural and physiological performance can covary within individuals. Additionally, the strength of this correlation can vary among individuals, and there may be fitness consequences of such individual heterogeneity. These patterns of covariation, inter-individual differences, and fitness consequences have been largely unstudied in ectothermic amniotes despite that reptiles have both behavioural lability and extreme physiological flexibility. We test the fitness consequences of complex phenotypes by combining measures of hormonal function, behaviour in two contexts, and reproductive success in females of the garter snake Thamnophis elegans. We find that these snakes are consistent over time in behavioral traits, but not physiological traits. Furthermore, these traits interact to affect the birth condition of their offspring, which subsequently bears enormous influence on growth and survivorship. Those moms fitting a “low reactivity” profile – characterized by reduced levels of stress hormone (corticosterone) and available energy stores (glucose), slower escape behavior, and reduced information-gathering via tongue flicking – gave birth to offspring in better body condition that, in turn, grew faster and lived longer under captive conditions. This study provides empirical support to connect axes of individual variation with fitness and furthermore proposes a mechanism for how such individual differences may be maintained within populations.
