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-like Receptor 7 (NPYLR7) is required for this behavioral switch, but its physiological role and sites of action were unknown. We identify a specialized, non-neuronal population of npylr7-expressing cells in the rectal pads of the mosquito hindgut. While this tissue is associated with fluid and ion balance, npylr7 mutants maintain fluid regulation but show impaired oocyte provisioning. These cells display neuroendocrine features, including calcium responses to the NPYLR7 ligand RYamide and amino acids, as well as expression of neurotransmitter synthesis and vesicle release machinery. Vesicle recruitment occurs in these cells post-blood meal in wild-type, but not npylr7 mutants. Our findings reveal an unexpected role for NPYLR7 in a rectal cell population senses nutritional cues and communicates with the nervous system to regulate reproductive physiology, paralleling gut-brain circuits in mammals.