Juvenile hormone acts through Methoprene tolerant to modulate female receptivity and sex pheromones in Drosophila melanogaster . Julide Bilen¹, Jade Atallah², Reza Azanchi¹, Joel Levine², Lynn Riddiford¹. 1) Janelia Farm Research Campus HHMI, Ashburn, VA; 2) Department of Biology, University of Toronto, Ontario, Canada.

   In 1966 Manning suggested that juvenile hormone (JH) was necessary for the normal maturation of female receptivity to a courting male in Drosophila melanogaster, but this role has been little studied. JH is secreted by the corpora allata (CA), starting just before adult eclosion. To determine the role of JH in maturation of female receptivity, we genetically ablated the CA by expressing diphtheria toxin at the late pupal stage. Comparison of the time course of the receptivity of allatectomized and control females showed that CA ablation significantly delayed the onset of female receptivity. Application of the JH mimic (JHM), methoprene, to these allatectomized females not only restored the normal timing of receptivity but also higher doses caused a precocious onset of receptivity. To determine whether JH modulated female attractiveness, we examined male courtship behavior with a decapitated female that had minimal rejection behaviors. The allatectomized females were less attractive than intact control females. The application of JHM rescued female attractiveness. Assays of the cuticular hydrocarbons showed that JH affected the female-specific, sex pheromone diene blend. In Drosophila the JH receptor is encoded by two duplicated genes, Methoprene-tolerant (Met) and germ cell expressed (gce). We found that a null allele of Met caused a similar delay in female receptivity. Paradoxically, the loss of function of Met increased female attractiveness apparently by increasing the long chain sex-specific dienes. In contrast, the loss of function of gce had no effect on either receptivity or attractiveness in the females. Together these findings suggest that JH acts through Met to modulate female receptivity and sex pheromone synthesis.