title: Female extra-pair mating: adaptation or genetic constraint?
abstract: Why do females of so many socially monogamous species regularly engage in matings outside the pair bond? This question has puzzled behavioural ecologists for more than two decades. Until recently, an adaptionist's point of view prevailed: if females actively seek extra-pair copulations, as has been observed in several species, they must somehow benefit from this behaviour. However, do they? In this review, we argue that adaptive scenarios have received disproportionate research attention, whereas nonadaptive phenomena, such as pathological polyspermy, de novo mutations, and genetic constraints, have been neglected by empiricists and theoreticians alike. We suggest that these topics deserve to be taken seriously and that future work would benefit from combining classical behavioural ecology with reproductive physiology and evolutionary genetics.
authors.affiliation: Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, 82319 Seewiesen, Germany. Electronic address: forstmeier@orn.mpg.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Forstmeier
authors.affiliation: Department of Zoology, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Nakagawa
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.
authors.forename: Simon C
authors.initials: SC
authors.lastname: Griffith
authors.affiliation: Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, 82319 Seewiesen, Germany.
authors.forename: Bart
authors.initials: B
authors.lastname: Kempenaers
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D005260:Female; D056084:Genetic Fitness / Q000502:physiology; D018095:Germ-Line Mutation; D006801:Humans; D012098:Reproduction / Q000235:genetics*; D012725:Sexual Behavior / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000502:physiology*