Genotype‐by‐environment interactions for cuticular hydrocarbon expression in <i><scp>D</scp>rosophila simulans</i>

<jats:title>Abstract</jats:title><jats:p>Genotype‐by‐environment interactions (<jats:styled-content style="fixed-case">G</jats:styled-content> × <jats:styled-content style="fixed-case">E</jats:styled-content>s) describe genetic variation for phenotypic plasticity. Recent interest in the role of these interactions in sexual selection has identified <jats:styled-content style="fixed-case">G</jats:styled-content> × <jats:styled-content style="fixed-case">E</jats:styled-content>s across a diverse range of species and sexual traits. Additionally, theoretical work predicts that <jats:styled-content style="fixed-case">G</jats:styled-content> × <jats:styled-content style="fixed-case">E</jats:styled-content>s in sexual traits could help to maintain genetic variation, but could also disrupt the reliability of these traits as signals of mate quality. However, empirical tests of these theoretical predictions are scarce. We reared iso‐female lines of <jats:italic><jats:styled-content style="fixed-case">D</jats:styled-content>rosophila simulans</jats:italic> across two axes of environmental variation (diet and temperature) in a fully factorial design and tested for <jats:styled-content style="fixed-case">G</jats:styled-content> × <jats:styled-content style="fixed-case">E</jats:styled-content>s in the expression of cuticular hydrocarbons (<jats:styled-content style="fixed-case">CHC</jats:styled-content>s), a multivariate sexual trait in this species. We find sex‐specific environmental, genetic and <jats:styled-content style="fixed-case">G</jats:styled-content> × <jats:styled-content style="fixed-case">E</jats:styled-content> effects on <jats:styled-content style="fixed-case">CHC</jats:styled-content> expression, with <jats:styled-content style="fixed-case">G</jats:styled-content> × <jats:styled-content style="fixed-case">E</jats:styled-content>s for diet in both male and female <jats:styled-content style="fixed-case">CHC</jats:styled-content> profile and a <jats:styled-content style="fixed-case">G</jats:styled-content> × <jats:styled-content style="fixed-case">E</jats:styled-content> for temperature in females. We also find some evidence for ecological crossover in these <jats:styled-content style="fixed-case">G</jats:styled-content> × <jats:styled-content style="fixed-case">E</jats:styled-content>s, and by quantifying variance components, genetic correlations and heritabilities, we show the potential for these <jats:styled-content style="fixed-case">G</jats:styled-content> × <jats:styled-content style="fixed-case">E</jats:styled-content>s to help maintain genetic variation and cause sexual signal unreliability in <jats:italic><jats:styled-content style="fixed-case">D</jats:styled-content>. simulans </jats:italic><jats:styled-content style="fixed-case">CHC</jats:styled-content> profiles.</jats:p>