title: Darwinian sex roles confirmed across the animal kingdom.
abstract: Since Darwin's conception of sexual selection theory, scientists have struggled to identify the evolutionary forces underlying the pervasive differences between male and female behavior, morphology, and physiology. The Darwin-Bateman paradigm predicts that anisogamy imposes stronger sexual selection on males, which, in turn, drives the evolution of conventional sex roles in terms of female-biased parental care and male-biased sexual dimorphism. Although this paradigm forms the cornerstone of modern sexual selection theory, it still remains untested across the animal tree of life. This lack of evidence has promoted the rise of alternative hypotheses arguing that sex differences are entirely driven by environmental factors or chance. We demonstrate that, across the animal kingdom, sexual selection, as captured by standard Bateman metrics, is indeed stronger in males than in females and that it is evolutionarily tied to sex biases in parental care and sexual dimorphism. Our findings provide the first comprehensive evidence that Darwin's concept of conventional sex roles is accurate and refute recent criticism of sexual selection theory.
authors.affiliation: Centre d'Écologie Fonctionnelle et Évolutive, UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, École Pratique des Hautes Études, 1919 Route de Mende, 34293 Montpellier Cedex 05, France.
authors.forename: Tim
authors.identifier: 0000-0002-1453-6813
authors.initials: T
authors.lastname: Janicke
authors.affiliation: Animal Evolutionary Ecology Group, Institute for Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
authors.forename: Ines K
authors.initials: IK
authors.lastname: Häderer
authors.affiliation: Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA.
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Lajeunesse
authors.affiliation: Animal Evolutionary Ecology Group, Institute for Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
authors.forename: Nils
authors.initials: N
authors.lastname: Anthes
mesh_terms: D000818:Animals; D005075:Biological Evolution; D005260:Female; D056084:Genetic Fitness; D008297:Male; D008954:Models, Biological; D010802:Phylogeny; D012641:Selection, Genetic; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal
keywords: Anisogamy; Bateman’s principles; Mating success; Sexual dimorphism; Sexual selection; parental care