Utility of the mitochondrial cytochrome oxidase II gene for resolving relationships among black flies (Diptera : Simuliidae)

The complete mitochondrial cytochrome oxidase II gene was sequenced from 17 black flies, representing 13 putative species, and used to infer phylogene tic relationships, A midge (Paratanytarsus sp,) and three mosquitoes (Aedes aegypti, Anopheles quadrimaculatus, and Culex quinquefasciatus) were used as outgroup taxa, All outgroup taxa were highly divergent from black flies. Phylogenetic trees based on weighted parsimony (a priori and a posteriori) , maximum likelihood, and neighbor-joining (log-determinant distances) diff ered topologically, with deeper nodes being the least well-supported. All a nalyses supported current classification into species groups but relationsh ips among those groups were poorly resolved. The majority of phylogenetic s ignal came from closely related sister taxa, The CO-II gene may be useful f or exploring relationships at or below the subgeneric level, but is of ques tionable value at higher taxonomic levels. The weighting method employed ga ve phylogenetic results similar to those reported by other authors for othe r insect CO-II data sets. A best estimate of phylogenetic relationships bas ed on the CO-II gene is presented and discussed in relation to current blac k fly classification. (C) 2000 Academic Press.