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Title
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Age-dependent relationships between multiple sexual pigments and condition in males and females
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Author
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Abstract
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| Coloration in birds can advertise individual condition to prospective mates. However, in yellow warblers (Setophaga petechia), the extent to which different types of coloration indicated condition varied with individual age. Yellow warblers display yellow carotenoid-based coloration and red-brown, melanin-based coloration. These types of coloration showed unique relationships to condition in different age classes, and age-dependent patterns were also sex specific. Thus, age-dependent signaling may favor multifaceted sexual displays and show sex-specific dynamics.The reliability of sexual signaling may change across age classes due to shifts in resource allocation patterns. Two contrasting hypotheses exist regarding how the condition dependence of ornaments may shift with age, and both have received empirical support. On one hand, ornaments may more reliably reflect condition and quality in older individuals, because younger individuals of high quality invest in survival over signaling effort. On the other hand, the condition dependence of ornaments may decline with age, if older individuals in poor condition terminally invest in ornaments, or if resource constraints decline with age. Further, the expression and condition dependence of different ornaments may shift with age in unique ways, such that multifaceted sexual displays maintain reliable signaling across age classes. In yellow warblers (Setophaga petechia) of both sexes, we assessed how relationships between carotenoid- and phaeomelanin-based sexual pigmentation, prenesting body reserves, and condition at molt (reflected by growth bars and feather quality) vary across age classes. Melanin coverage correlated with condition at molt across age classes in males and showed high repeatability in both sexes. In contrast, carotenoid saturation increased longitudinally with age in males and correlated with condition at molt in different age classes in the 2 sexes. Specifically, carotenoid saturation correlated positively with condition at molt in younger, but not older males, whereas in females, the situation was reversed, with a positive correlation present only in older females. Results suggest that age-dependent signaling may promote maintenance of multifaceted sexual displays and that age-dependent signaling dynamics depend on sex. |
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Language
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English
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Source (journal)
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Behavioral ecology / International Society for Behavioral Ecology. - New York, NY
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Publication
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New York, NY
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2014
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ISSN
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1045-2249
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DOI
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10.1093/BEHECO/ART124
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Volume/pages
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25
:2
(2014)
, p. 276-287
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ISI
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000336484600010
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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