TitleMolecular parentage analysis in experimental newt populations: The response of mating system measures to variation in the operational sex ratio
Publication TypeJournal Article
Year of Publication2004
AuthorsJones, AG, Arguello, JR, Arnold, SJ
JournalAmerican Naturalist
KeywordsBateman gradient index of resource monopolization microsatellites Morisita index parentage sexual selection potential reproductive rates rough-skinned newt taricha-granulosa sperm precedence selection variance success opportunity males competition

Molecular studies of parentage have been extremely influential in the study of sexual selection in the last decade, but a consensus statistical method for the characterization of genetic mating systems has not yet emerged. Here we study the utility of alternative mating system measures by experimentally altering the intensity of sexual selection in laboratory-based breeding populations of the rough-skinned newt. Our experiment involved skewed sex ratio ( high sexual selection) and even sex ratio ( low sexual selection) treatments, and we assessed the mating system by assigning parentage with microsatellite markers. Our results show that mating system measures based on Bateman's principles accurately reflect the intensity of sexual selection. One key component of this way of quantifying mating systems is the Bateman gradient, which is currently underutilized in the study of genetic mating systems. We also compare inferences based on Bateman's principles with those obtained using two other mating system measures that have been advocated recently (Morisita's index and the index of resource monopolization), and our results produce no justification for the use of these alternative measures. Overall, our results show that Bateman's principles provide the best available method for the statistical characterization of mating systems in nature.