Project description:Objective: Sexually dimorphic phenotypes arise largely from sex-specific gene expression, which has mainly been characterized in sexually naïve adults. However, we expect sexual dimorphism in transcription to be dynamic and dependent on factors such as reproductive status. Mating induces many behavioral and physiological changes distinct to each sex and is therefore expected to activate regulatory changes in many sex-biased genes. Methods: Using RNA-seq we first characterized sexual dimorphism in gene expression, for the first time in Callosobruchus maculatus seed beetles. We then examined how females and males respond to mating and how it affects sex-biased expression, both in more sex-limited (abdomen) and sex-shared (head and thorax) tissues. Results: Mating responses were largely sex-specific and, as expected, females showed more numerous changes compared to males. Of the sex-biased genes present in virgins, 16% (1,041 genes) in the abdomen and 17% (243 genes) in the head and thorax altered their relative expression between the sexes. Sex-bias status changed in 2% of the genes in the abdomen and 4% in the head and thorax following mating. Mating responses involved de-feminization of females and, to a lesser extent, de-masculinization of males relative to their virgin state: mating decreased rather than increased dimorphic expression of sex-biased genes.
