title: Sexual selection: placentation, superfetation, and coercive copulation.
abstract: The evolution of placentas in poeciliid fishes is associated with conception of overlapping litters and male mating strategies becoming more coercive. Sperm competition in ovaries of multiply-inseminated females may favor fertilization of immature eggs during ongoing pregnancies.
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA. Electronic address: dhaig@oeb.harvard.edu.
authors.forename: David
authors.initials: D
authors.lastname: Haig
mesh_terms: D000818:Animals; D003532:Cyprinodontiformes / Q000145:classification* / Q000502:physiology*; D005260:Female; D008297:Male; D010802:Phylogeny; D012726:Sexual Behavior, Animal / Q000502:physiology*; D052286:Viviparity, Nonmammalian / Q000502:physiology*