Sex peptide targets distinct higher order processing neurons in the brain to induce the female post-mating response.

Abstract

Sex peptide (SP) transferred during mating induces female post-mating responses including refractoriness to re-mate and increased oviposition in <i>Drosophila</i>. Yet, where SP-target neurons reside remained uncertain. Here, we show that expression of membrane-tethered SP (mSP) predominantly in the head or trunk either reduces receptivity or increases oviposition, respectively. Using fragments from large regulatory regions of <i>Sex Peptide Receptor</i>, <i>fruitless,</i> and <i>doublesex</i> genes together with intersectional expression of mSP, we identified distinct interneurons in the brain and abdominal ganglion controlling receptivity and oviposition. These SP response-inducing neurons (SPRINz) can induce post-mating responses through SP received by mating. Trans-synaptic mapping of neuronal connections reveals input from sensory processing neurons and two post-synaptic trajectories as output. Hence, SP-target neurons operate as key integrators of sensory information for decision-making of behavioural outputs. Multi-modularity of SP-targets further allows females to adjust SP-mediated male manipulation to physiological state and environmental conditions for maximising reproductive success.