Phylogenetic relationships among the microgastroid wasps (Hymenoptera : Braconidae): Combined analysis of 16S and 28S rDNA genes and morphological data

Relationships among the microgastroid complex of braconid wasps were invest igated using sequence data from the 16S mitochondrial rDNA and 285 (D2 expa nsion region) nuclear rDNAgenes, as well as morphological data. Parsimony a nalysis of these gene fragments, both separately and combined, indicated th at Neoneurus (Neoneurinae) and Ichneutes (Ichneutinae) were no more closely related to the microgastroids than were a range of helconoid taxa. Combine d parsimony analysis of the microgastroids indicated the relationships ((Ca rdiochilinae + Microgastrinae) + Miracinae) + Cheloninae, with Adeliinae fa lling inside the Cheloninae. Bootstrap proportions for each of these nodes were greater than 70%. Character reweighting (sensu Farris), using the resc aled consistency index, also recovered these relationships. Mapping of life style traits onto this relatively well supported phylogeny indicated that s olitary endoparasitism is ancestral for the microgastroids, with a single o rigin for egg-larval endoparasitism in the Cheloninae + Adeliinae. Mapping of the radiation of the microgastroids into lepidopteran hosts was less cle ar, due to the specialized biology of the most basal microgastroid clade, t he Cheloninae + Adeliinae. Our data are consistent with attack of concealed lepidopteran hosts as the plesiomorphic lifestyle, at least for the Miraci nae + Cardiochilinae + Microgastrinae, with radiation into more exposed hos ts in the Cardiochilinae + Microgastrinae. (C) 1998 Academic Press.