Sex peptide regulates female receptivity through serotoninergic neurons in Drosophila

The courtship ritual is a dynamic interplay between males and females. Courtship successfully leading to copulation is determined by the intention of both parties which is conveyed by complex action sequences. In Drosophila, the neural mechanisms controlling the female’s willingness to mate, or sexual receptivity, have only recently become the focus of investigations. Here, we report that pre-mating sexual receptivity in females requires activity within a subset of serotonergic projection neurons (SPNs), which positively regulate courtship success. Of interest, a male-derived sex peptide, SP, which was transferred to females during copulation acted to inhibit the activity of SPN and suppressed receptivity. Downstream of 5-HT, subsets of 5-HT7 receptor neurons played critical roles in SP-induced suppression of sexual receptivity. Together, our study reveals a complex serotonin signaling system in the central brain of Drosophila which manages the female’s desire to mate.