The current taxonomic status of the Culicoides vectors of bluetongue viruses.

In the regions where bluetongue (BT) viruses are known to occur the taxomonic literature is generally adequate for confident identification of the commoner species that are the most likely vectors. Unfortunately in each region there are difficult taxonomic problems in the accurate determination of some proven or potential vectors. These problems involve the so-called imicola and obsoletus groups of the subgenus Avaritia, the variipennis complex in the subgenus Monoculicoides and the schultzei group of the ill-defined subgenus Oecacta. In the imicola and schultzei groups sophisticated taxonomic studies now in progress have been successful in finding useful morphological as well as biological characters for recognition of the vector species. In the variipennis complex morphologically distinct eastern and western populations can be recognized, but their characteristics with respect to ease of colonization and ability to transmit BT virus (BTV) are not yet well known. The taxonomic status of the subspecies of variipennis known to breed in saline and alkaline habitats is still confused and badly in need of detailed study.