Breeding Habitat Preferences of Major Culicoides Species (Diptera: Ceratopogonidae) in Germany

Biting midges of the genus Culicoides (Diptera, Ceratopognidae) are demonstrably or putatively involved in the transmission of both bluetongue (BTV) and Schmallenberg viruses (SBV) in Central Europe. Although these insects are ubiquitous in Europe, relatively little is known about their requirements in terms of breeding habitats and substrates. Culicoides species composition and relative abundance in potential breeding habitats were therefore studied at various locations in Northeastern Germany and one location in Western Germany by emergence trap collections. Forty-three potential breeding sites were analyzed in ten landscape structures, with 28,091 adult biting midges emerging from them. Among these, 2116 specimens belonged to the genus Culicoides. Species of the culicoid subgenus Avaritia were most abundant (70.6% of all specimens) and widespread (91.6% of all sites), while the subgenus Culicoides accounted for 15.6% of the specimens registered but emerged from 70.8% of all sites sampled. Culicoides species of other subgenera were collected in 75.0% of all studied sites, with a relative abundance of 8.7%. The results indicate that various types of dung, but probably also some landscape habitats, offer suitable substrates for the development of potential Culicoides vector species. Adaptations in dung management on farms and landscape design and use might therefore be appropriate approaches to reduce the risk of BTV or SBV transmission.