The Culicoides biting midge, a tiny fly in the order Diptera, transmits several important animal viruses. One of the most significant is the bluetongue virus, which causes bluetongue disease in cattle, sheep, deer and other ruminants. A new study gets closer to answering how biting midges such as Culicoides sonorensis (shown here) maintain transmission of bluetongue virus to cattle in temperate regions year after year, even though individual midges are unlikely to survive entire winters. (Photo by Xinmi Zhang, Ph.D.)