Sexual selection on male body size, genital length and heterozygosity: Consistency across habitats and social settings
Date
2017
Authors
Head, Megan
Kahn, Andrew T.
Henshaw, Jonathan
Keogh, J. Scott
Jennions, MIchael D
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
Spatial and temporal variation in environmental factors and the social setting can help to maintain genetic variation in sexually selected traits if it affects the strength of directional selection. A key social parameter which affects the intensity of, and sometimes predicts the response to, mating competition is the operational sex ratio (OSR; ratio of receptive males to females). How the OSR affects selection for specific male traits is poorly understood. It is also unclear how sexual selection is affected by interactions between the OSR and environmental factors, such as habitat complexity, that alter key male-female interactions such as mate encounter rates. Here, we experimentally manipulated the OSR and habitat complexity and quantified sexual selection on male mosquitofish (Gambusia holbrooki) by directly measuring male reproductive success (i.e. paternity). We show that despite a more equitable sharing of paternity (i.e. higher levels of multiple paternity) under a male-biased OSR, selection on focal male traits was unaffected by the OSR or habitat complexity. Instead, sexual selection consistently, and significantly, favoured smaller bodied males, males with higher genome wide heterozygosity (based on >3,000 SNP markers) and males with a relatively long gonopodium (intromittent organ). Our results show that sexual selection on male body size, relative genital size and heterozygosity in this system is consistent across environments that vary in ecological parameters that are expected to influence mate encounter rates.
Description
Keywords
hfc, body size, environmental heterogeneity, poeciliid, reproductive success, animals, cyprinodontiformes, genitalia, male, male, reproduction, body size, ecosystem, mating preference, animal, sex ratio
Citation
Collections
Source
The Journal of animal ecology
Type
Journal article
Book Title
Entity type
Access Statement
Open Access