Mating activates neuroendocrine pathways signaling hunger in Drosophila females

Mated females reallocate resources to offspring production, causing changes in nutritional requirements and challenges to energy homeostasis. Although observed in most species, the neural and endocrine mechanisms that regulate the nutritional needs of mated females are not well understood. Here, we investigate the neural circuitry that regulates sugar appetite in mated Drosophila melanogaster females. During copulation, a male-derived sex peptide is transferred to females, silencing the mating status circuit to elicit many postmating behavioral changes ^1-3 . We find that increased sucrose consumption is a postmated female behavior and show that it is mediated by the mating status circuit. We discovered that sexually dimorphic insulin receptor (Lgr3) neurons integrate mating status and nutritional state signals to adjust sucrose consumption. Lgr3+ cells receive inhibitory input from the mating status circuit via female specific pCd-2 neurons. In mated females, the inhibition of Lgr3 cells from pCd-2 is attenuated, transforming the mated signal into a long-term hunger signal that promotes sugar intake. Our results thus demonstrate that the mating circuit alters nutrient sensing centers in females to promote sugar consumption, providing a mechanism to increase intake in anticipation of the energetic costs associated with reproduction.