"Le coût de l'infidélité pour la femelle chez le Bruant des roseaux"

Behavioral Ecology
2009 20(3):601-608;
doi:10.1093/beheco/arp037

The cost of infidelity to female reed buntings

Stefan M. Suter, Joanna Bielanska, Sabine Röthlin-Spillmann, Ludivine Strambini and Dietrich R. Meyer

Department of Biology, Unit for Ecology and Evolution, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland

Abstract

Females of many socially monogamous bird species accept or even actively seek copulations outside the social pair bond. It has been shown that females profit from extrapair fertilization by increased offspring quality, but extrapair mating may also induce costs to females. We measured parental food provisioning and paternity in the reed bunting, Emberiza schoeniclus, a species with biparental brood care and high levels of extrapair paternity (EPP). We found a negative relationship between the proportion of EPP in broods and paternal care across the local population. Individual males adjusted food provisioning to the amount of EPP between sequential broods. Females did compensate for low male food provisioning. The cost of extrapair fertilizations to females is increased nestling mortality due to the social partner's reduction of brood care. If the mixed mating system of the reed bunting is at an evolutionary equilibrium, we expect that genetic fitness for males as well as for females is maximized. Any costs incurred by extrapair mating should therefore not exceed the benefits for both @#$%&.

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Généralités et Environnement

L'infidélité ne paie pas...