Receptor for the neuropeptide SIFamide (PubMed:16378592). Modulates sexual behavior by playing a role in male sex discrimination (PubMed:26469541). Also involved in promoting sleep (PubMed:24658384). In the larva, expressed in a bilateral pair of neurons in each of the abdominal rhabdomeres. In the adult, expressed predominantly in the central nervous system with expression also detected in two neurons in the uterus. RNAi-mediated knockdown causes a significant reduction in total sleep amount (PubMed:24658384). It also causes significant male-male courtship behavior although a number of flies appear to behave normally (PubMed:26469541). Belongs to the G-protein coupled receptor 1 family.