Raphaël Royauté, Ann Hedrick, Ned A Dochtermann

When selection differs by sex, the capacity for sexes to reach optimal phenotypes can be constrained by the shared genome of males and females. Because phenotypic traits are often correlated, this difference extends across multiple traits and underlying genetic correlations can further constrain evolutionary responses. Behaviors are frequently correlated as behavioral syndromes, and these correlations often have a genetic basis. However, whether cross-sex and across behavior correlations lead constrained evolution remains unknown. Here, we show that a boldness-activity syndrome is strongly sex-specific at the genetic level in the western field cricket (Gryllus integer) and that emergence from a shelter is genetically independent between males and females. However, male activity is strongly related to female shelter emergence, creating the potential for biased responses to selection. Our results show that the sex-specific genetic architecture of behavioral syndromes can shape the evolution of behavioral phenotypes.