title: The evolution of sex roles in mate searching.
abstract: Searching for mates is a critical stage in the life cycle of most internally, and many externally, fertilizing species. Males usually invest more in this costly activity than females, but the reasons for this are poorly understood. Previous models have shown that female-biased parental investment, including anisogamy, does not by itself select for male-biased mate searching, so it requires additional explanations. Here, we correct and expand upon earlier models, and present two novel hypotheses that might explain the evolution of male-biased mate searching. The "carry-over hypothesis" states that females benefit less from searching if the associated costs affect other stages of the life cycle, rather than arising only while searching. It is relevant to the evolution of morphological traits that improve searching efficiency but are also expressed in other contexts. The "mating window hypothesis" states that females benefit less from searching if their life cycle includes intervals during which the exact timing of mating does not matter for the appropriate timing of reproduction (e.g., due to sperm storage or delayed embryo implantation). Such intervals are more likely to exist for females given the general pattern of greater female parental investment. Our models shed new light on classic arguments about sex role evolution.
authors: Department of Biological and Environmental Science, University of Jyvaskyla, P.O. Box 35, 40014, Jyvaskyla, Finland. lutzfromhage@web.de.
authors: Lutz
authors: L
authors: Fromhage
authors: Ecology, Evolution & Genetics, Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
authors: Michael
authors: M
authors: Jennions
authors: Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.
authors: Hanna
authors: H
authors: Kokko
mesh_terms: D000818:Animals; D005075:Biological Evolution; D005260:Female; D056084:Genetic Fitness; D008297:Male; D052586:Mating Preference, Animal; D008954:Models, Biological; D012726:Sexual Behavior, Animal
keywords: Mating effort; models/simulations; parental investment; sex roles