Mating Changes Sexually Dimorphic Gene Expression in the Seed Beetle Callosobruchus maculatus

Area of Science:

• Evolutionary biology
• Genetics
• Reproductive biology

Background:

• Sexually dimorphic phenotypes result from sex-specific gene expression, typically studied in sexually naive adults.
• Reproductive status, such as mating, is expected to dynamically influence transcriptional sexual dimorphism.

Purpose of the Study:

• To characterize sexual dimorphism in gene expression in Callosobruchus maculatus seed beetles.
• To investigate the impact of mating on sex-biased gene expression in both sexes and across different tissues (abdomen, head, thorax).

Main Methods:

• Gene expression profiling in male and female seed beetles before and after mating.
• Analysis of sex-biased gene expression in sex-limited (abdomen) and sex-shared (head and thorax) tissues.

Main Results:

• Mating induced significant, sex-specific gene expression changes, with females exhibiting a larger response than males.
• A notable percentage of sex-biased genes in virgin beetles altered their expression post-mating, leading to shifts in sex-bias status.
• Mating resulted in a decrease in dimorphic expression of sex-biased genes, indicating a de-feminization effect in females and de-masculinization in males.

Conclusions:

• Sexual dimorphism in gene expression is dynamic and significantly influenced by mating status.
• Mating triggers regulatory changes in sex-biased genes in both sexes, challenging the assumption of restricted selection pressures.
• The observed de-feminization and de-masculinization suggest complex regulatory interactions underlying mating-induced phenotypic changes.