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Sexual selection on male body size, genital length and heterozygosity: Consistency across habitats and social settings
Author(s) -
Head Megan L.,
Kahn Andrew T.,
Henshaw Jonathan M.,
Keogh J. Scott,
Jennions Michael D.
Publication year - 2017
Publication title -
journal of animal ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.134
H-Index - 157
eISSN - 1365-2656
pISSN - 0021-8790
DOI - 10.1111/1365-2656.12742
Subject(s) - biology , gambusia , operational sex ratio , sexual selection , mosquitofish , reproductive success , ecology , mating , mate choice , selection (genetic algorithm) , directional selection , zoology , mating system , evolutionary biology , demography , genetic variation , population , genetics , artificial intelligence , fishery , sociology , fish <actinopterygii> , computer science , gene
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 ( G ambusia 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.