title: Sexual conflict over parental care promotes the evolution of sex differences in care and the ability to care.
abstract: Strong asymmetries in parental care, with one sex providing more care than the other, are widespread across the animal kingdom. At present, two factors are thought to ultimately cause sex differences in care: certainty of parentage and sexual selection. By contrast, we here show that the coevolution of care and the ability to care can result in strong asymmetries in both the ability to care and the level of care, even in the absence of these factors. While the coevolution of care and the ability to care does not predict which sex evolves to care more than the other, once other factors give rise to even the slightest differences in the cost and benefits of care between the sexes (e.g. differences in certainty in parentage), a clear directionality emerges; the sex with the lower cost or higher benefit of care evolves both to be more able to care and to provide much higher levels of care than the other sex. Our findings suggest that the coevolution of levels of care and the ability to care may be a key factor underlying the evolution of sex differences in care.
authors.affiliation: School of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW, UK john.mcnamara@bristol.ac.uk.
authors.forename: John M
authors.initials: JM
authors.lastname: McNamara
authors.affiliation: Department of Biology and Ecology of Fishes, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin 12587, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Wolf
mesh_terms: D000818:Animals; D005260:Female; D005716:Game Theory; D008297:Male; D008425:Maternal Behavior / Q000502:physiology*; D010332:Paternal Behavior / Q000502:physiology*; D012737:Sex Factors; D012726:Sexual Behavior, Animal / Q000502:physiology*
keywords: parental care; parental effort; sex differences; sexual conflict