Research Areas

Species of the subgenus Culicoides based on ITS2 sequences

Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) include vectors for the economically important animal diseases, bluetongue (BT) and African horse sickness (AHS). In the Mediterranean Basin these diseases are transmitted by four species of Culicoides: the first three belong in the subgenus Avaritia Fox and are C. imicola Kieffer, C. obsoletus (Meigen) and C. scoticus Downes and Kettle; the fourth is C. pulicaris (Linnaeus) in the subgenus Culicoides Latreille. In the Palaearctic Region this subgenus (usually referred to as the C. pulicaris group) now includes a loose miscellany of some 50 taxa. The lack of clarity surrounding its taxonomy stimulated the present morphological and molecular study of 11 species collected in Italy. Phylogenetic analysis of nuclear ribosomal DNA ITS2 sequence variation demonstrated a high degree of divergence. These results, combined with those from a parallel morphological study, disclosed: 1. that some previously described taxa should be resurrected from synonymy; 2. that there are new species to be described, and 3. that the subgenus Culicoides (as currently employed) is a polyphyletic assemblage of four lineages - the subgenus Culicoides sensu stricto, the subgenus Silvicola Mirzaeva and Isaev, the subgenus Hoffmania Fox and the hitherto unrecognised Fagineus species complex. Strong congruence between morphological and molecular data holds promise for resolving many of the difficult taxonomic issues plaguing the accurate identification of vector Culicoides around the world.