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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]
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/
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 |
| UTAS Author: | Wapstra, E (Associate Professor Erik Wapstra) |
| ID Code: | 110429 |
| Year Published: | 2016 |
| Funding Support: | Australian Research Council (FT110100597) |
| Web of Science® Times Cited: | 6 |
| Deposited By: | Zoology |
| Deposited On: | 2016-07-27 |
| Last Modified: | 2017-10-31 |
| Downloads: | 116 View Download Statistics |
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