Live fast, die young: trade-offs between fitness components and sexually antagonistic selection on weaponry in Soay sheep.

Détails

ID Serval
serval:BIB_509079D13BD3
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Live fast, die young: trade-offs between fitness components and sexually antagonistic selection on weaponry in Soay sheep.
Périodique
Evolution
Auteur(s)
Robinson M.R., Pilkington J.G., Clutton-Brock T.H., Pemberton J.M., Kruuk L.E.
ISSN
0014-3820 (Print)
ISSN-L
0014-3820
Statut éditorial
Publié
Date de publication
2006
Peer-reviewed
Oui
Volume
60
Numéro
10
Pages
2168-2181
Langue
anglais
Résumé
Males are predicted to compete for reproductive opportunities, with sexual selection driving the evolution of large body size and weaponry through the advantage they confer for access to females. Few studies have explored potential trade-offs of investment in secondary sexual traits between different components of fitness or tested for sexually antagonistic selection pressures. These factors may provide explanations for observed polymorphisms in both form and quality of secondary sexual traits. We report here an analysis of selection on horn phenotype in a feral population of Soay sheep (Ovis aries) on the island of Hirta, St. Kilda, Scotland. Soay sheep display a phenotypic polymorphism for horn type with males growing either normal or reduced (scurred) horns, and females growing either normal, scurred, or no (polled) horns; further variation in size exists within horn morphs. We show that horn phenotype and the size of the trait displayed is subject to different selection pressures in males and females, generating sexually antagonistic selection. Furthermore, there was evidence of a trade-off between breeding success and longevity in normal-horned males, with both the normal horn type and larger horn size being associated with greater annual breeding success but reduced longevity. Therefore, selection through lifetime breeding success was not found to act upon horn phenotype in males. In females, a negative association of annual breeding success within the normal-horned phenotype did not result in a significant difference in lifetime fitness when compared to scurred individuals, as no significant difference in longevity was found. However, increased horn size within this group was negatively associated with breeding success and longevity. Females without horns (polled) suffered reduced longevity and thus reduced lifetime breeding success relative the other horn morphs. Our results therefore suggest that trade-offs between different components of fitness and antagonistic selection between the sexes may maintain genetic variation for secondary sexual traits within a population.

Mots-clé
Animals, Biological Evolution, Female, Horns, Longevity, Male, Phenotype, Reproduction, Sex Characteristics, Sexual Behavior, Animal, Sheep/anatomy & histology, Sheep/physiology
Pubmed
Web of science
Création de la notice
06/12/2017 13:42
Dernière modification de la notice
03/03/2018 17:09
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