The relationship between behavioral profiles and corticosterone in great tits Parus major


Meeting Abstract

P2.22  Wednesday, Jan. 5  The relationship between behavioral profiles and corticosterone in great tits Parus major BAUGH, Alexander T*; VAN OERS, Kees; HAU, Michaela; Max Planck Institute for Ornithology: Migration and Immuno-ecology; Netherlands Institute for Ecology: Animal Ecology; Max Planck Institute for Ornithology: Migration and Immuno-ecology alex.baugh@gmail.com

A growing body of research in behavioral ecology examines behavioral co-variation and repeatability within individuals, and in many species there is a high degree of both. What are the mechanisms that might serve as the basis for such “behavioral profiles” or “coping styles”? Stress physiology and glucocorticoids (CORT) have received particular attention in this regard. We examined the relationship between plasma CORT levels and behavioral profiles in a European passerine, the great tit Parus major and test the hypothesis that slower (more “reactive”) individuals will have an elevated response to a standardized stressor. Using a capture-restraint stress protocol and a population of captive adult great tits bi-directionally selected for fast and slow exploratory behavior we examined the effect of selection line and performance in these assays on CORT secretion. For each subject, we collected a blood sample within 3 min of disturbance (“baseline”), 15 min following disturbance (“Cort15”) and at 30 min (“Cort30”). We found a robust stress response across subjects (mean [CORT] ± SE, ng ml-1): baseline (10.9±1.06), Cort15 (37.6±1.8) and Cort30 (52.8±2.6). Virtually all individuals experienced an elevation in CORT at each consecutive time-point. There was no evidence, however, of any relationship between the CORT measures (baseline, maximum, and total integrated CORT) and selection line or performance on the behavioral assays. These results are discussed with respect to the psychological context of the stressor, the potential influence of living conditions (captive versus wild populations) on the stress response, and alternative mechanisms that may explain variance in behavioral profiles.

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