RT Journal Article
SR Electronic
T1 Environmental unpredictability shapes glucocorticoid regulation across populations of tree swallows
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2019.12.23.887075
DO 10.1101/2019.12.23.887075
A1 Cedric Zimmer
A1 Conor C. Taff
A1 Daniel R. Ardia
A1 Alexandra P. Rose
A1 David A. Aborn
A1 L. Scott Johnson
A1 Maren N. Vitousek
YR 2019
UL http://biorxiv.org/content/early/2019/12/23/2019.12.23.887075.abstract
AB Responding appropriately to challenges is an important contributor to fitness. Variation in the regulation of glucocorticoid hormones, which mediate the phenotypic response to challenges, can therefore influence the ability to persist in a given environment. We compared stress responsiveness in four populations of tree swallows (Tachycineta bicolor) along an environmental gradient to evaluate support for different selective pressures in driving the evolution of glucocorticoid regulation. In accordance with the environmental unpredictability hypothesis, stronger stress responses were seen in more unpredictable environments. Contrary to the reproductive value hypothesis, the stress response was not lower in populations engaging in more valuable reproductive attempts. Populations with stronger stress responses also had stronger negative feedback, which supports a “mitigating” rather than a “magnifying” effect of negative feedback on stress responses. These results suggest that combining a robust stress response with strong negative feedback may be important for persisting in unpredictable or rapidly changing environments.