Parental Absence Primes Hypothalamic-Pituitary-Adrenal Axis Activity In Tree Swallow (Tachycineta bicolor) Nestlings
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Authors
Heft, Megan C.
Issue Date
2020-11-01
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Stress responses serve to enhance fitness by allowing individuals to deal with diverse stressors like predator attacks or food shortages. Stressors are not all equivalent in intensity or duration, and though the physiological responses to different events often overlap, the context in which stress is experienced can change the degree or duration of a given response. We conducted behavioral research on nestling tree swallows ( Tachycineta bicolor ) to establish average levels of parental attendance and to determine whether parental attendance (social presence) would serve as a predictor of baseline corticosterone (CORT) for nestlings. In order to determine whether parental attendance acts as a “social buffer” on nestling CORT responses, we conducted a series of parental exclusions from nest boxes before subjecting nestlings to a capture-restraint protocol. Initial CORT concentrations were elevated in our long exclusion group compared to baseline CORT in controls. Within stress-induced samples, CORT in parentally-restricted nestlings was also elevated, which suggests that the hypothalamo-pituitary-adrenal (HPA) axis was primed, if not activated, by the exclusions. Parental attendance thus appears to exhibit both “social presence” and social buffering effects. We found no significant correlations between parental behaviors and nestling baseline CORT. Overall, our results suggest that both social presence and social buffering act as a proximate mechanism in the regulation of circulating CORT in nestlings.
Description
v, 31 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.