Preliminary evolutionary relationships within the parasitoid wasp genus Cotesia (Hymenoptera: Braconidae: Microgastrinae): Combined analysis of four genes

The braconid wasp genus Cotesia Cameron (Braconidae: Microgastrinae) is one of the largest genera of parasitoid wasps, and its species are employed frequently as biological control agents against pest insects. Several Cotesia species are also used as model organisms in physiology, ecology and population genetics studies. The genus thus has considerable importance from both applied and basic science perspectives. We investigated the phylogenetic relationships of twenty-five species of Cotesia commonly used in field and laboratory research, using the genes 16S, ND1, 28S and LW opsin and employing a range of phylogeny estimation methods including maximum parsimony, maximum likelihood, minimum evolution and Bayesian inference. Phylogenetic estimates differed little among methods, especially for the combined data analysis. The combined analysis of four genes identified four well-supported clades within Cotesia: the melanoscela group (containing C. melanoscela, the C. flavipes species complex and probably also C. ruficrus), the kariyai group (containing C. kariyai, C. kazak, C. cyaniridis, C. flaviconchae and probably also C. anisotae and C. griffini), the rubecula group (containing C. congregata, C. electrae, C. euchaetis, C. marginiventris, C. obsuricornis and C. schizurae), and the glomerata group (consisting of C. glomerata, C. melitaearum and C. plutellae), plus a basal unresolved complex including C. hyphantriae, C. diacrisiae and C. empretiae. These groups correspond poorly with previous broad subgroups of Cotesia defined by Papp based on morphology. The current work constitutes the first real framework for comparative studies in systematics, ecology, physiology and population genetics of Cotesia. A preliminary analysis of the evolution of gregarious development from solitary is presented, in which it is apparent that solitary development is ancestral, and gregariousness has arisen several times independently within separate groups.