Hypersensitivity controlled by mir-9a modulates female receptivity of Drosophila melanogaster.

Female Drosophila melanogaster undergo a complex behavioral transformation following mating, characterized by increased sensory sensitivity and altered reproductive behaviors. In this study, we investigated the role of miR-9a, a conserved microRNA, in regulating these post-mating changes. We found that miR-9a mutant females exhibited a hypersensitivity phenotype, with increased rejection of courting males, delayed onset of sexual receptivity, and abnormal mating termination behavior. This phenotype was associated with aberrant overgrowth of adult body wall sensory neurons, suggesting a link between neuronal hypersensitivity and reproductive behavior. To further elucidate the underlying mechanisms, we performed genetic interaction studies with sens and bru2, genes known to interact with miR-9a. We found that removing one copy of sens or bru2 in miR-9a mutant backgrounds rescued the female rejection phenotype and normalized neuronal morphology. This suggests that miR-9a regulates sensory neuron development and female receptivity by modulating the expression of target genes like sens and bru2. Our findings reveal a novel role for miR-9a in regulating sensory hypersensitivity and reproductive behaviors in Drosophila. This research provides valuable insights into the molecular mechanisms underlying post-mating behavioral adaptations and neural development. Additionally, our findings highlight the potential of Drosophila as a model organism for investigating the role of miR-9 family members in neuronal specification and function, with implications for understanding sensory processing and neural plasticity in other organisms.