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Corticosterone: a costly mediator of signal honesty in sand lizards

Citation

Lindsay, WR and Wapstra, E and Silverin, B and Olsson, M, Corticosterone: a costly mediator of signal honesty in sand lizards, Ecology and Evolution, 6, (20) pp. 7451-7461. ISSN 2045-7758 (2016) [Refereed Article]


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Copyright Statement

Copyright 2016 The Authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/

DOI: doi:10.1002/ece3.2318

Abstract

The mechanisms underlying honest signal expression remain elusive and may involve the integration of social and physiological costs. Corticosterone is a socially modulated metabolic hormone that mediates energy investment and behavior and may therefore function to deter dishonest signal expression. We examined the relationship between corticosterone and green badge coloration in male sand lizards (Lacerta agilis), hypothesizing that physiological and behavioral costs resulting from elevated baseline glucocorticoids function in maintenance of honest signal expression. We found that large-badged males had higher corticosterone titer, with this relationship apparent at the end of the season and absent early in the season. Large-badged males also suffered higher ectoparasite load (number of tick nymphs), despite being in better condition than small-badged males. Ectoparasite load was positively related to corticosterone titer early in the season at the time of badge formation. High-condition individuals had lower corticosterone and lower numbers of ectoparasites than low-condition individuals, suggestive of conditional variation in ability to withstand costs of corticosterone. We found an opposing negative relationship between corticosterone titer and endoparasite load. Corticosterone titer was also negatively associated with male mobility, a fitness-determining behavior in this species. Because badge size is involved in mediating agonistic social interactions in this species, our results suggest that badge-dependent variation in corticosterone is likely reflective of variation in social conditions experienced over the course of the season. Our results implicate corticosterone in maintenance of signal honesty, both early in the season through enforcement of physiological costs (ectoparasite load) and during the season through behavioral costs (male mobility). We propose that socially modulated variation in corticosterone critically functions in mediation of signal honesty without requiring a direct role for corticosterone in trait expression.

Item Details

Item Type:Refereed Article
Keywords:badge size, coloration, ectoparasite, endoparasite, glucocorticoids, Lacerta agilis, lizard
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Behavioural Ecology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Environmental Sciences
Author:Wapstra, E (Associate Professor Erik Wapstra)
ID Code:110429
Year Published:2016
Funding Support:Australian Research Council (FT110100597)
Deposited By:Zoology
Deposited On:2016-07-27
Last Modified:2017-10-31
Downloads:21 View Download Statistics

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