Molecular phylogenetics of Vespoidea indicate paraphyly of the superfamily and novel relationships of its component families and subfamilies

The 24 000+ described species of Vespoidea include many well-known stinging wasps, such as paper wasps and hornets (Vespidae), velvet ants (Mutillidae), spider wasps (Pompilidae) and ants (Formicidae). The compelling behaviours of vespoids have been instrumental in developing theories of stepwise evolutionary transitions, which necessarily depend on an understanding of phylogeny, yet, existing morphological phylogenies for Vespoidea conflict. We collected molecular data from four nuclear genes (elongation factor-1α F2 copy, long-wavelength rhodopsin, wingless and the D2–D3 regions of 28S ribosomal RNA (2700 bp in total)) to produce the first molecular phylogeny of Vespoidea. We analysed molecular data alone and in combination with published morphological data from Brothers and Carpenter. Parsimony analyses left many deeper nodes unsupported, but suggested paraphyly of three families. Total-evidence Bayesian inference produced a more resolved tree, in which the monophyly of Vespoidea was nevertheless ambiguous. Bayesian inference of molecular data alone returned a well-resolved consensus with posterior probabilities of over 95% for most nodes. We used this topology as the best estimate of phylogeny at the family and subfamily levels. Notable departures from previous estimates include: (i) paraphyly of Vespoidea resulting from the nesting of Apoidea within a lineage comprising Formicidae, Scoliidae and two subfamilies of Bradynobaenidae; (ii) paraphyly of Bradynobaenidae, Mutillidae and Tiphiidae; (iii) a sister relationship between Rhopalosomatidae and Vespidae; and (iv) Rhopalosomatidae + Vespidae as sister to all other vespoids/apoids. We discuss character evidence in light of the new phylogeny, and propose a new classification of Aculeata that recognizes eight superfamilies: Apoidea, Chrysidoidea, Formicoidea, Pompiloidea, Scolioidea, Tiphioidea, Thynnoidea and Vespoidea.