Meeting Abstract
Effectively coping with stressors may involve not only mounting a vigorous stress response, but efficiently and effectively terminating this response to return to normal behaviors and physiological processes. Yet while the phenotypic and fitness effects of mounting a strong hormonal stress response have been widely studied, much less is known about whether individual variation in the ability to terminate the stress response through negative feedback influences performance and fitness. Recent findings in free-living tree swallows (Tachycineta bicolor) have begun to elucidate the role of individual variation in negative feedback in predicting both resilience to and recovery from challenges. The efficacy of negative feedback is typically measured through circulating glucocorticoid levels, but the downstream effects of varying GC levels are mediated through receptor binding. Ongoing experiments are also beginning to illuminate how receptor expression, and potential epigenetic mediators of receptor expression, may influence individual variation in negative feedback, and its fitness effects. Overall, our results suggest that the ability to rapidly terminate the stress response through negative feedback may be an important determinant of why some individuals, and some populations, cope with challenges more effectively than others.
