The regulatory role of m6A RNA methylation in insect sexual development: a review.

N6-methyladenosine (m6A) is the most prevalent internal mRNA modification in eukaryotes and serves as a key post-transcriptional regulator in insect development. This review synthesizes current knowledge on m6A in insect sexual development, beginning with its well-established role in Drosophila melanogaster, where it ensures female fate by promoting the female-specific splicing of the master switch gene Sex-lethal (Sxl). Notably, classical female-lethal genes such as Fl(2)d and Virilizer are now recognized as essential regulatory subunits of the m6A methyltransferase complex, linking classic genetics to epitranscriptomics. In insects lacking an Sxl-centric pathway, such as Coleoptera, Hymenoptera, and Lepidoptera, m6A depletion does not disrupt core sex differentiation but instead plays essential roles in related processes, including metamorphosis in Tribolium, caste differentiation in honey bees, and gametogenesis across multiple orders.These findings underscore that m6A functions extend beyond the initial sex determination switch to regulate a broad spectrum of sex-related developmental processes across insect taxa, providing insights into the evolution of epigenetic regulation.