D3241: Circadian rhythms of Culicoides sonorensis biting midges infected with arboviruses

The biting midge Culicoides sonorensis (Diptera: Ceratopogonidae) is a nuisance pest and an important vector of viral pathogens of livestock that cause significant economic damage worldwide, such as bluetongue virus (BTV) and vesicular stomatitis virus (VSV). Previous research has demonstrated that these arboviruses can disseminate to the sensory tissues of Culicoides, including the ommatidia and cerebral ganglia. We hypothesize that viral infection of these tissues alters midge sensory functions, leading to changes in their circadian rhythmic behaviors. In this study, we utilized Drosophila activity monitors (DAMs) to evaluate the circadian activity of C. sonorensis. Colonized C. sonorensis females were microinjected with either purified BTV, VSV, or sterile PBS. Four days post-injection, midges were placed in DAMs, and their movement, rest, and position were recorded for 96 hours. Recordings were repeated monthly from March through October. Changes in periods of rest, movement, and response to light as a result of arbovirus infection were noted. This study provides a foundational understanding of C. sonorensis circadian activity and offers insight into how arbovirus infection influences these behaviors. These findings contribute to our understanding of the behavioral changes associated with arboviral infection in biting midges which could help improve management and trapping strategies.