decepentaplegic directs wiring of female-differentiated fruitless sex peptide response-inducing neurons

Female reproductive success requires coordinated behavioural responses following mating. In Drosophila melanogaster, these responses are induced by male-derived sex-peptide (SP) and include reduced receptivity to further mating and increased oviposition. Although the neural pathways controlling these behaviours have been partially characterized, the developmental mechanisms that establish and maintain these circuits remain poorly understood. Using a genetic approach, we identified an EMS-induced mutant that retains eggs and fails to reduce receptivity following SP exposure. We mapped this mutation to the transcription termination zone after the polyA site of the dpp locus and show that this allele dppHB3 affects expression. Dpp/BMP signalling acts within SP response-inducing neurons (SPRINz) and is required for correct neuronal wiring in dppHB3 mutants. We further find that the SPRINZ-fru11/12 enhancer induces gene expression upon Dpp exposure. Also, female sexual differentiation trough the sex determination gene tra is required in SPRINz to display post-mating behaviours. Together, these findings suggest a new role for dpp in specifying neuronal connectivity in the context of sexual differentiation by the Drosophila canonical sex determination pathway to implement neuronal wiring for post-mating behaviours.