title: Evidence for frequent incest in a cooperatively breeding mammal.
abstract: As breeding between relatives often results in inbreeding depression, inbreeding avoidance is widespread in the animal kingdom. However, inbreeding avoidance may entail fitness costs. For example, dispersal away from relatives may reduce survival. How these conflicting selection pressures are resolved is challenging to investigate, but theoretical models predict that inbreeding should occur frequently in some systems. Despite this, few studies have found evidence of regular incest in mammals, even in social species where relatives are spatio-temporally clustered and opportunities for inbreeding frequently arise. We used genetic parentage assignments together with relatedness data to quantify inbreeding rates in a wild population of banded mongooses, a cooperatively breeding carnivore. We show that females regularly conceive to close relatives, including fathers and brothers. We suggest that the costs of inbreeding avoidance may sometimes outweigh the benefits, even in cooperatively breeding species where strong within-group incest avoidance is considered to be the norm.
authors.affiliation: Faculty of Science, Liverpool John Moores University, Liverpool L3 3AF, UK h.j.nichols@ljmu.ac.uk.
authors.forename: H J
authors.initials: HJ
authors.lastname: Nichols
authors.affiliation: College of Life and Environmental Sciences, University of Exeter, Exeter TR10 9FE, UK.
authors.forename: M A
authors.initials: MA
authors.lastname: Cant
authors.affiliation: Department of Animal Behaviour, Bielefeld University, Bielefeld 33501, Germany.
authors.forename: J I
authors.initials: JI
authors.lastname: Hoffman
authors.affiliation: College of Life and Environmental Sciences, University of Exeter, Exeter TR10 9FE, UK.
authors.forename: J L
authors.initials: JL
authors.lastname: Sanderson
mesh_terms: D000818:Animals; D005260:Female; D008297:Male; D008322:Mammals / Q000502:physiology*; D008969:Molecular Sequence Data; D012726:Sexual Behavior, Animal
keywords: cooperative breeding; dispersal; inbreeding; incest; life-history evolution; reproductive competition