Effects of ultraviolet LED versus incandescent bulb and carbon dioxide for sampling abundance and diversity of Culicoides in Florida.

Biting midges (Ceratopogonidae: Culicoides) are vectors of bluetongue virus and epizootic hemorrhagic disease virus which cause significant morbidity and mortality in ruminants. Recently, ultraviolet light emitting diodes (UV/LEDs) in conjunction with suction traps have been widely utilized for Culicoides spp. collections. Despite the use of these traps, limited work has been done comparing sampling variability associated with these light types with and without CO2. For this objective, mini-CDC light traps with four different attractant combinations were operated at eight sites across Florida between April and October 2017. Trap attractants included white-incandescent lights and UV/LEDs with and without CO2 to determine optimum combinations of light type and attractant for species richness, diversity, and abundance of Culicoides spp. in Florida. The results of the study demonstrate that traps with UV/LED light collect greater richness, diversity, and abundance of Culicoides species than traps with white-incandescent light. Addition of CO2 resulted in greater diversity in traps with UV/LED lights, but lower diversity in traps with white-incandescent light. Therefore, CO2 may be used to increase the abundance of Culicoides spp. collected by traps, regardless of light type, but the ability for CO2 to attract a higher number and diversity of species to traps varies by the light type used. Therefore, we suggest using CO2 primarily in conjunction with UV/LED light. When CO2 is not available, UV/LED light used alone can be substituted without a significant loss in species richness or diversity, although abundance of most Culicoides species will be significantly lower in the absence of CO2.