Meeting Abstract
Physiology facilitates the interaction between the environment and organismal fitness; thus, individual endocrine stress responses are likely to be fundamentally important for population-level responses to seasonal or environmental change. Glucocorticoids mediate trade-offs among energetic allocations and maintain homeostasis in response to stressors while also modulating day-to-day functions including feeding, locomotor activity, energy metabolism, and immune function. While glucocorticoids, such as corticosterone, are often assayed to evaluate the physiological response to stress by the hypothalamic-pituitary-interrenal (HPI) axis, other biomarkers of stress, such as circulating levels of blood glucose, provide additional measures by which we can quantify organismal responses to environmental variation. Here we use natural populations of the western terrestrial garter snake (Thamnophis elegans) representing two ecotypes from the Sierra Nevada Mountain range, near Eagle Lake CA, to quantify plasma levels of both baseline and stress-induced corticosterone and glucose across this species’ active season. The populations that represent these ecotypes are part of a long-term study system that provides an ideal natural laboratory to test for the effects of seasonality on both individual and population level stress responses. We found that baseline and stress-induced physiological measures differed between ecotypes and across the active season.
