Simultaneous analysis of 16S, 28S, COI and morphology in the Hymenoptera: Apocrita - evolutionary transitions among parasitic wasps

Simultaneous analysis of morphological and molecular characters from the 16S rDNA, 28S rDNA and cytochrome oxidase 1 genes was employed to resolve phylogenetic relationships among the apocritan (Insecta: Hymenoptera: Apocrita) wasps. Parsimony analyses, employing a broad range of models, consistently recovered the Proctotrupomorpha as a natural group, the Megalyridae and Trigonalidae as sister groups, a clade comprising the Monomachidae, Diapriidae, and Maamingidae, the Vanhorniidae and Proctotrupidae as sister groups, the Proctotrupoidea as polyphyletic, and the Evaniomorpha as a grade (but including the Ichneumonoidea, Aculeata, and Stephanidae). The Proctotrupomorpha, containing virtually all of the wholly endoparasitic lineages, was consistently recovered as an apical clade, with the remaining groups forming a paraphyletic grade below them. Although the relative placement of the groups forming this basal grade varied among analyses, the most commonly recovered arrangement is consistent with the ancestral biology being ectoparasitism of coleopteran, wood-boring larvae. Furthermore, the recovery of the ectoparasitic-containing proctotrupomorphs (Chalcidoidea and, in some analyses, Ceraphronoidea) as apical lineages argues that these biologies are reversals. (C) 2001 The Linnean Society of London.