A signaling hub in the mosquito rectum coordinates reproductive investment after blood feeding

After a blood meal, female Aedes aegypti mosquitoes suppress host-seeking while converting ingested nutrients into yolk protein for egg development. Neuropeptide Y-related pathways regulate feeding in many animals, and loss of neuropeptide Y-like receptor 7 (NPYLR7) disrupts host-seeking regulation in Aedes aegypti. However, its physiological role and sites of action were unknown. Here, we identify a specialized, non-neuronal population of npylr7-expressing cells in the rectal pads of the mosquito hindgut. Although this tissue is generally associated with fluid and ion balance, npylr7 mutants maintain intact fluid regulation but show impaired oocyte provisioning. These cells display neuroendocrine features, including calcium responses to the NPYLR7 ligand RYamide and to amino acids, as well as expression of neurotransmitter synthesis and vesicle release machinery. Vesicle recruitment occurs in these cells after blood feeding in wild-type females but not in npylr7 mutants. Our findings reveal an unexpected role for a conserved neuropeptide receptor in a rectal cell population that is capable of sensing nutritional cues and communicating with the nervous system to regulate reproductive physiology, paralleling gut-brain circuits in mammals.