Male reproductive genes influencing mating and fertility: enhancing the sterile insect technique and genetic control of Diptera pests

Diptera include major agricultural pests and disease vectors, underscoring the need for species-specific population-control strategies. The sterile insect technique (SIT) relies on sterile males that remain sufficiently viable and competitive to mate successfully with wild females without producing viable offspring. This review synthesizes male reproductive genes and regulatory pathways in Diptera according to the reproductive processes they control and the failure modes caused by their disruption. Mechanistic understanding is based largely on studies of Drosophila melanogaster, complemented by evidence from tephritid fruit flies and mosquitoes to assess conservation and operational relevance in pest and vector species. We examine testis morphogenesis, germline maintenance, meiotic and post-meiotic spermatogenesis, sperm function, accessory gland-mediated post-mating responses, and noncoding RNA regulation. The responsible genetic networks are evaluated in relation to sterility penetrance, reproductive specificity, pleiotropic fitness costs, mating performance, residual fertility, and post-mating reproductive effects. Functional studies using RNA interference and genome editing have identified promising targets for male fertility, necessitating species-specific evaluation to determine their suitability for genetic control. By correlating reproductive mechanisms with operational phenotypes, this synthesis can inform target prioritization, strain maintenance, and quality control of irradiated males, thereby enhancing the refinement of SIT and related genetic control strategies.