Phylogenetic relationships of yellowjackets inferred from nine loci (Hymenoptera: Vespidae, Vespinae, Vespula and Dolichovespula)

Eusociality has arisen repeatedly and independently in insects, each time leading to evolutionary success and ecological dominance. Eusocial wasps of the genera Vespula and Dolichovespula, or yellowjackets, have developed advanced social traits in a relatively small number of species. The origin of traits such as effective paternity and colony size has been interpreted with reference to an established phylogenetic hypothesis that is based on phenotypic data. So far, the application of molecular evidence to phylogenetic analysis within yellowjackets has been limited. We investigate the evolutionary history of yellowjackets on the basis of mitochondrial and nuclear markers (nuclear: 28S, EF1α, Pol II, wg; mitochondrial: 12S, 16S, COI, COII, and Cytb). We use parsimony and Bayesian methods to infer the relationships of yellowjacket genera, test the monophyly of species groups, and resolve species-level relationships within each yellowjacket genus. Our results either ambiguously supported (parsimony) or rejected (Bayesian inference) a yellowjacket clade. But the monophyly of each yellowjacket genus as well as taxonomic species groups are strongly supported and concordant among methods. Our study agrees with previous studies regarding the monophyly of the Vespula vulgaris group and the sister group relationship between the V. rufa group and V. squamosa. This suggests convergence of large colony size and high effective paternity in the vulgaris group and V. squamosa, or a single origin of both traits in the most recent common ancestor of all Vespula species and their evolutionary loss in the rufa group.