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Investigating glucocorticoid and behavioral responses to food and social cues in a highly irruptive, nomadic songbird.

Research output: Contribution to conferenceAbstract

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Original languageEnglish
Publication statusPublished - 2016
EventEleventh International Symposium on Avian Endocrinology - Ontario, Niagara-on-the Lake, Canada
Duration: 11 Oct 201614 Oct 2016

Conference

ConferenceEleventh International Symposium on Avian Endocrinology
CountryCanada
CityNiagara-on-the Lake
Period11/10/1614/10/16

Abstract

Facultative migrants move in response to unpredictable fluctuations in resources and are well documented to exhibit mass movements if resources are declining and competition is high. Making an appropriate departure decision (i.e., to move or not to move) is presumably under strong selection – given the importance of sufficient food for survival and reproduction. We have previously demonstrated that reducing food availability of captive red crossbills (Loxia curvirostra), an irruptive and nomadic conifer seed specialist, induces increased activity levels and plasma corticosterone. More surprisingly, these changes in plasma corticosterone were modified depending on social information provided by a neighbor. Close proximity to a food-reduced neighbor enhanced the corticosterone response to food manipulation relative to those who were given access to an ad libitum-fed neighbor. These data suggested that social cues may influence departure decisions by altering underlying mechanisms (i.e., corticosterone physiology). We repeated this experiment to determine if social cues influence hypothalamus-pituitary-adrenal (HPA) axis sensitivity through altered expression of glucocorticoid receptors (GR) and mineralocorticoid receptors (MR) mRNA in the hippocampus or hypothalamus using in situ hybridization. As predicted, public information from food-restricted individuals reduced MR mRNA expression in the hippocampus thereby allowing increased or sustained HPA-activity during subsequent stressors; MR plays a role in negative feedback. Such a mechanism may explain why food reduced crossbills paired with food reduced neighbors show higher corticosterone secretion than those paired with ad libitum-fed neighbors. Interestingly, food reduction itself appeared to have no measurable influence on MR or GR mRNA expression. Research supported by the BBSRC to SLM.

Event

Eleventh International Symposium on Avian Endocrinology

11/10/1614/10/16

Niagara-on-the Lake, Canada

Event: Conference

ID: 26531349