Corticosterone mediates the condition-dependent component of melanin-based coloration

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State: Public
Version: author
Serval ID
serval:BIB_8641B0C5AC8D
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Corticosterone mediates the condition-dependent component of melanin-based coloration
Journal
Animal Behaviour
Author(s)
Roulin A., Almasi B., Rossi-Pedruzzi A., Ducrest A. L., Wakamatsu K., Miksik I., Blount J. D., Jenni-Eiermann S., Jenni L.
ISSN
0003-3472
Publication state
Published
Issued date
2008
Peer-reviewed
Oui
Volume
75
Number
4
Pages
1351-1358
Language
english
Abstract
The handicap principle of sexual selection theory states that colourful phenotypic traits signal aspects of individual quality because only individuals in prime condition can afford to produce and bear conspicuous traits. Melanin-based pigments participate in the elaboration of many secondary sexual characters and, given their role in sexual selection, melanin-based coloration may therefore honestly reject individual quality. Although the expression of melanism is usually under genetic control, in some species it is condition dependent. However, the underlying physiological mechanism is yet unknown. Based on the negative feedback link between corticosterone and melanogenesis ( melanocortins, tyrosinase) in response to stressful environmental factors, we hypothesize that corticosterone mediates the condition-dependent component of melanism. This hypothesis predicts that stressful factors induce a rise in circulating corticosterone which inhibits the secretion of melanocortins and tyrosinase and in turn melanin production. We tested this prediction by manipulating the level of corticosterone at the time of melanin production in nestling barn owls, Tyto alba, a species showing heritable variation in the degree of phaeomelanism from reddish-brown to white. The finding that corticosterone-implanted nestlings produced feathers with less phaeomelanic coloration than placebo-implanted nestlings is consistent with the hypothesis that the environment-mediated reduction in the degree of melanism is, at least in part, caused by a rise in corticosterone. In species in which the expression of melanin-based coloration is condition dependent, we now need a test showing that individuals with less corticosterone and more melanin-based signals are individuals in better condition.
Keywords
barn owl, colour polymorphism, corticosterone, handicap principle, melanin, sexual selection, stress, Tyto alba
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Create date
24/01/2008 17:42
Last modification date
20/08/2019 14:45
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