Why do melanin ornaments signal individual quality? Insights from metal element analysis of barn owl feathers.

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State: Public
Version: author
Serval ID
serval:BIB_B23D212A68BE
Type
Article: article from journal or magazin.
Collection
Publications
Title
Why do melanin ornaments signal individual quality? Insights from metal element analysis of barn owl feathers.
Journal
Oecologia
Author(s)
Niecke M., Rothlaender S., Roulin A.
ISSN
0029-8549[print], 0029-8549[linking]
Publication state
Published
Issued date
2003
Volume
137
Number
1
Pages
153-158
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't Publication Status: ppublish
Abstract
Melanin-based variation in colour patterns is under strong genetic control and not, or weakly, sensitive to the environment and body condition. Current signalling theory predicts that such traits may not signal honestly phenotypic quality because their production does not entail a significant fitness cost. However, recent studies revealed that in several bird species melanin-based traits covary with phenotypic attributes. In a first move to understand whether such covariations have a physiological basis, we quantified concentrations of five chemical elements in two pigmented plumage traits in the barn owl (Tyto alba). This bird shows continuous variation from immaculate to heavily marked with black spots (plumage spottiness) and from dark reddish-brown to white (plumage coloration), two traits that signal various aspects of individual quality. These two traits are sexually dimorphic with females being spottier and darker coloured than males. We found an enhancement in calcium and zinc concentration within black spots compared with the unspotted feather parts. The degree to which birds were spotted was positively correlated with calcium concentration within spots, whereas the unspotted feather parts of darker reddish-brown birds were more concentrated in zinc. This suggests that two different pigments are responsible for plumage spottiness and plumage coloration. We discuss the implications of our results in light of recent experimental field studies showing that female spottiness signals offspring humoral response towards an artificially administrated antigen, parasite resistance and fluctuating asymmetry of wing feathers.
Keywords
Adaptation, Physiological, Animals, Color, Feathers/chemistry, Feathers/physiology, Female, Male, Melanins/analysis, Melanins/physiology, Pigmentation, Strigiformes/immunology, Strigiformes/physiology
Pubmed
Web of science
Create date
24/01/2008 17:42
Last modification date
20/08/2019 15:20
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