Fertility decline in female mosquitoes is regulated by theorcoolfactory co-receptor

Abstract

SUMMARYFemaleAedes aegyptimosquitoes undergo multiple rounds of reproduction, known as gonotrophic cycles. These cycles span the period from blood meal intake to oviposition. Understanding how reproductive success is maintained across gonotrophic cycles allows for the identification of molecular targets to reduce mosquito population growth. Odorant receptor co-receptor (orco) encodes a conserved insect-specific transmembrane ion channel that complexes with tuning odorant receptors (ORs) to form a functional olfactory receptor.orcoexpression has been identified in the male and female mosquito germline, but its role is unclear. We report anorco-dependent, maternal effect reduction in fertility after the first gonotrophic cycle. This decline was rescued by repairing theorcomutant locus. Eggs deposited byorcomutant females are fertilized but the embryos reveal developmental defects, reduced hatching, and changes in ion channel signaling gene transcription. We present an unexpected role for an olfactory receptor pathway in mosquito reproduction.HIGHLIGHTSLoss of theorcoolfactory co-receptor promotes female mosquito fertility decline.After their first reproductive cycle completes,Ae. aegypti orcomutant females produce embryos with disrupted development and reduced hatching.CRISPR/Cas9-mediated repair of theorcomutation rescues the fertility defect.Gene expression profiling of embryos fromorcomutant females supports a role for ion channel signaling in mosquito development.