Extra-pair paternity, testes size and testosterone level in relation to colour polymorphism in the barn owl Tyto alba

Détails

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Etat: Serval
Version: de l'auteur
ID Serval
serval:BIB_91E89A64CA97
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Extra-pair paternity, testes size and testosterone level in relation to colour polymorphism in the barn owl Tyto alba
Périodique
Journal of Avian Biology
Auteur(s)
Roulin A., Müller W., Sasvari L., Dijkstra C., Ducrest  A. L., Riols C., Wink M.
ISSN
0908-8857
Statut éditorial
Publié
Date de publication
2004
Peer-reviewed
Oui
Volume
35
Numéro
6
Pages
492-500
Langue
anglais
Résumé
In many bird populations, individuals display one of several genetically inherited colour morphs. Colour polymorphism can be maintained by several mechanisms one of which being frequency-dependent selection with colour morphs signalling alternative mating strategies. One morph may be dominant and territorial, and another one adopt a sneaky behaviour to gain access to fertile females. We tested this hypothesis in the barn owl Tyto alba in which coloration varies from reddish-brown to white. This trait is heritable and neither sensitive to the environment in which individuals live nor to body condition. In Switzerland, reddish-brown males were observed to feed their brood at a higher rate and to produce more offspring than white males. This observation lead us to hypothesize that white males may equalise fitness by investing more effort in extra-pair copulations. This hypothesis predicts that lighter Coloured males produce more extra-pair young, have larger testes and higher levels of circulating testosterone. However, our results are not consistent with these three predictions. First, paternity analyses of 54 broods with a total of 211 offspring revealed that only one young was not sired by the male that was feeding it. Second, testes size was not correlated with male plumage coloration suggesting that white males are not sexually more active. Finally, in nestlings at the time of feather growth testosterone level was not related to plumage coloration suggesting that this androgen is not required for the expression of this plumage trait. Our study therefore indicates that in the barn owl colour polymorphism plays no role in the probability of producing extra-pair young.
Mots-clé
WHITE-THROATED SPARROW, RUFF PHILOMACHUS-PUGNAX, ZONOTRICHIA-ALBICOLLIS GMELIN, COPULATORY-BEHAVIOR, PLUMAGE COLORATION, GENETIC-EVIDENCE, DNA, FEMALE, FERTILIZATIONS, HETEROZYGOSITY
Web of science
Création de la notice
24/01/2008 18:42
Dernière modification de la notice
03/03/2018 19:30
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