D3107: A closer look at vitellogenesis in the understudied vector, Culicoides sonorensis

Culicoides sonorensis biting midges are hematophagous dipterans, which vector multiple arboviruses to susceptible livestock. Female midges are able to transmit pathogens to naive hosts through blood feeding, as they require multiple blood meals throughout their lifespan to produce egg clutches. Although arboviruses transmitted by these insects result in severe economic losses to the livestock industry, there is a gap in knowledge concerning the characterization and molecular regulation of vitellogenesis in this understudied vector. To fill this gap in knowledge, we first used immunohistochemistry techniques to characterize follicular development in midge females throughout vitellogenesis. Using previously reported Christophers’ stages of the well-studied mosquito, we successfully major stages of follicular development. Furthermore, we followed expression of two potential vitellogenin orthologs in Culicoides using molecular biology techniques. Our data showed increased expression at 24 hours post blood meal (hpbm), which is similar to vitellogenin expression in mosquitoes. To confirm the location of vitellogenin expression in midges, ovary, midgut, abdominal walls (fat body), and remaining (head and thorax) tissues were dissected 24 hpbm. Our data showed that the majority of expression was found in the fat body. Together these data serve as a base for future work to determine the molecular mechanisms of vitellogenesis in C. sonorensis.