Species composition of Culicoides (Diptera: Ceratopogonidae) in the Ridge and Valley region of Tennessee, USA.

Biting midges in the genus Culicoides Latreille (Diptera: Ceratopogonidae) are known to transmit many pathogens of veterinary and medical concern. Although much work has been done globally and in certain regions of North America, Culicoides spp. research in rural Appalachia is limited. To begin characterizing the distribution and community structure of Culicoides spp. in Appalachia, we surveyed 2 distinct sites in the Ridge and Valley ecoregion of northeastern Tennessee, USA, from April 2021-September 2021. Culicoides spp. were sampled using 2 methods: Centers for Disease Control ultraviolet LED light traps and potential larval habitat substrate collection (coupled with water chemistry values). Site 1 was dominated by natural features, and Site 2 was a beef cattle operation. During 96 trap nights, a total of 1,568 Culicoides were collected, representing 24 species. Site 1 yielded the highest diversity, with 24 species, while Site 2 yielded 12 species. Overall, the most abundant species in light traps were C. stellifer Coquillett (44%), C. bergi Cochrane (18%), C. haematopotus Malloch (12%), and C. debilipalpis Lutz (11%). From substrate sampling, 8 species were identified. Culicoides haematopotus was the most abundant and was collected during each sampling period. Water chemistry values taken at the time of substrate collection were not significantly related to which Culicoides spp. emerged from a given substrate. Our results indicate a diverse community of Culicoides spp. in our study area, however, further work is needed to identify Culicoides species composition across a variety of landscapes in Appalachia and inform research on vector presence and associated vector disease dynamics.