Melanin pigmentation negatively correlates with plumage preening effort in barn owls

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Serval ID
serval:BIB_14CCE83A14DF
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Melanin pigmentation negatively correlates with plumage preening effort in barn owls
Journal
Functional Ecology
Author(s)
Roulin A.
ISSN
0269-8463
Publication state
Published
Issued date
2007
Peer-reviewed
Oui
Volume
21
Number
2
Pages
264-271
Language
english
Abstract
1. According to the handicap principle of sexual selection, colourful ornaments honestly signal absolute quality only if they entail fitness costs. The degree of melanism often covaries positively with aspects of individual quality, and hence melanin-based coloration should be costly to produce or to maintain in a good shape. This is, however, unlikely because melanin-based coloration is often strongly heritable and in birds the rate of feather wear decreases with the amount of melanin pigments packed in feathers.
2. The hypothesis that melanin pigments reduce the cost of maintaining colourful ornaments in a good shape predicts a negative correlation between the degree of melanism and both the size of the uropygial gland that produces preening secretions and the intensity of preening behaviour.
3. Using a correlative approach, I evaluated these two predictions in the barn owl Tyto alba in which the body underside varies from immaculate to heavily marked with black spots, a eumelanin-based trait, and from white to reddish-brown, a phaeomelanin-based trait. I correlated plumage traits with preening behaviour in nestlings and with the size and mass of the uropygial gland in dead adults. I also weighed nonornamental wing and tail feathers to assess whether the quality of nonornamental feathers is positively correlated with the degree of melanism of an ornamental plumage trait.
4. The degree of phaeomelanism was neither associated with preening behaviour nor with the size and mass of the uropygial gland. In line with the two predictions, individuals with more and larger black spots had a lighter uropygial gland and preened less frequently. Because nonornamental wing and tail feathers of spottier individuals were heavier per unit of surface area, the entire plumage of eumelanic individuals may be more robust and in turn require less care than the plumage of nonmelanic conspecifics.
5. In conclusion, the degree of eumelanism can be associated with aspects of individual quality even if eumelanic ornaments are neither costly to produce nor to maintain in a good shape.
Document Type: Article
Web of science
Open Access
Yes
Create date
24/01/2008 17:42
Last modification date
18/02/2020 7:08
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