title: Litter sex composition influences dominance status of Alpine marmots (Marmota marmota).
abstract: In social species, the hierarchical status of an individual has important consequences for its fitness. While many studies have focused on individual condition to explain access to dominance, very few have investigated the influence of the social environment, especially during early life. Yet it is known that environmental conditions early in life may influence several traits at adulthood. Here, we examine the influence of early social environment on accession to dominance by investigating the influence of litter size and sex composition on survival and the probability of ascending to dominance later in life using a 20-year dataset from a wild population of Alpine marmots (Marmota marmota). Although litter size had no effect on the fate of individuals, litter sex composition affected male juvenile survival and both male and female probabilities of reaching dominant status when adult. Male juveniles incur lower survival when the number of male juveniles in the litter increases, and individuals of both sexes from male-biased litters are more likely to become dominant than individuals from female-biased litters. However, the absolute number of sisters in the litter, rather than the sex ratio, seems to be an important predictor of the probability of acquiring dominant status: pups having more sisters are less likely to become dominant. Several potential mechanisms to explain these results are discussed.
authors.affiliation: Laboratoire de Biométrie et Biologie Évolutive, UMR 5558, CNRS, Université Lyon 1, Université de Lyon, 43 Boulevard du 11 Novembre 1918, Villeurbanne, 69622, France. pierre.dup@live.fr.
authors.forename: Pierre
authors.initials: P
authors.lastname: Dupont
authors.affiliation: EPHE, Université Paul-Valéry Montpellier, Université de Montpellier, CNRS, CEFE UMR 5175, 1919 Route de Mende, Montpellier Cedex 5, 34293, France.
authors.forename: Roger
authors.initials: R
authors.lastname: Pradel
authors.affiliation: Laboratoire de Biométrie et Biologie Évolutive, UMR 5558, CNRS, Université Lyon 1, Université de Lyon, 43 Boulevard du 11 Novembre 1918, Villeurbanne, 69622, France.|Groupe Écologie et Conservation, Université d'Angers, Angers, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Lardy
authors.affiliation: Laboratoire de Biométrie et Biologie Évolutive, UMR 5558, CNRS, Université Lyon 1, Université de Lyon, 43 Boulevard du 11 Novembre 1918, Villeurbanne, 69622, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Allainé
authors.affiliation: Laboratoire de Biométrie et Biologie Évolutive, UMR 5558, CNRS, Université Lyon 1, Université de Lyon, 43 Boulevard du 11 Novembre 1918, Villeurbanne, 69622, France. aurelie.cohas@univ-lyon1.fr.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Cohas
mesh_terms: D000818:Animals; D004777:Environment; D005260:Female; D006608:Hierarchy, Social; D006801:Humans; D008098:Litter Size; D008297:Male; D008392:Marmota / Q000502:physiology*; D012737:Sex Factors; D012744:Sex Ratio
keywords: Delayed effects; Group composition; Multi-event models; Reproduction access; Rodent; Social context