title: Paternity and dominance loss in male breeders: the cost of helpers in a cooperatively breeding mammal.
abstract: Paternity insurance and dominance tenure length are two important components of male reproductive success, particularly in species where reproduction is highly skewed towards a few individuals. Identifying the factors affecting these two components is crucial to better understand the pattern of variation in reproductive success among males. In social species, the social context (i.e. group size and composition) is likely to influence the ability of males to secure dominance and to monopolize reproduction. Most studies have analyzed the factors affecting paternity insurance and dominance tenure separately. We use a long term data set on Alpine marmots to investigate the effect of the number of subordinate males on both paternity insurance and tenure of dominant males. We show that individuals which are unable to monopolize reproduction in their family groups in the presence of many subordinate males are likely to lose dominance the following year. We also report that dominant males lose body mass in the year they lose both paternity and dominance. Our results suggest that controlling many subordinate males is energetically costly for dominant males, and those unable to support this cost lose the control over both reproduction and dominance. A large number of subordinate males in social groups is therefore costly for dominant males in terms of fitness.
authors.affiliation: UMR CNRS 5558 Biométrie et Biologie Evolutive, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Lardy
authors.forename: Aurélie
authors.initials: A
authors.lastname: Cohas
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Desouhant
authors.forename: Marion
authors.initials: M
authors.lastname: Tafani
authors.forename: Dominique
authors.initials: D
authors.lastname: Allainé
mesh_terms: D000818:Animals; D001835:Body Weight; D001947:Breeding; D003163:Competitive Behavior; D004291:Dominance-Subordination; D005260:Female; D008297:Male; D008392:Marmota / Q000502:physiology*; D012098:Reproduction / Q000502:physiology*; D012737:Sex Factors; D012726:Sexual Behavior, Animal / Q000502:physiology*; D013997:Time Factors