Molecular phylogenetics of blackflies of the Simulium damnosum complex and cytophylogenetic implications

The molecular phylogenetics of the Simulium damnosum complex, including vectors of the human parasite Onchocerca volvulus, from various parts of Africa was studied and compared with results of cytogenetic analyses. The sequence data of mitochondrial 16s and nuclear ITS2 rDNA revealed that the complex comprises two main clades, roughly covering the more easterly and westerly African taxa, respectively. However, striking inconsistencies in the tree topologies turned up between the DNA fragments regarding the position of certain subcomplexes and species. The cytophylogenetic relationships are better reflected in the ITS2 tree where Simulium pandanophilum and Simulium mengense constitute a basal, Central African clade of the entire complex and are therefore suggested to be the chromosomal roots too. Further divisions and the corresponding biogeographic interpretations are discussed. Several species and cytoforms are placed within the system for the first time. The phylogenetic relationships within the complex do hardly correlate with host preferences or other behavioral and ecological characteristics.