Meeting Abstract
Individual behavioral differences in response to challenging conditions can vary across two different dimensions: the quality of the response (reactive or proactive coping style) and the quantity of the response (hypothalamic-pituitary-adrenal axis activity). However, the relationship between these dimensions has not been extensively explored with relation to developmental stress exposure, an important factor considering the known influence of developmental stress on endocrine structures. Our study examines the impact of maternal stress during the perinatal period on coping behavior and stress reactivity of wild juvenile North American red squirrels. First, to explore the correlational association between behavioral traits and stress reactivity in red squirrels, we used fecal samples and open-field trials on adults in 2008-2010. Next, to assess the causal role of maternal stress, we manipulated developmental stress exposure by feeding mothers glucocorticoids during pregnancy or lactation and tracked juveniles after emergence from the nest. To quantify coping styles of juveniles, we measured three behavioral traits (aggression, activity, and docility) using an open-field trial and docility trial. To assess stress reactivity, we performed dexamethasone and ACTH challenges on juvenile squirrels around the period of weaning and measured plasma cortisol concentrations. This study will further our understanding of how individual differences in behavioral responses may be influenced by endocrine structures shaped by the organizational effects of maternal hormones during the perinatal period.
