Molecular systematics of the parasitoid subfamily Phasiinae (Diptera: Tachinidae)

The subfamily Phasiinae (Diptera: Tachinidae) is composed of obligate endoparasitoid flies that attack heteropteran insects, including many important agricultural pests. Phasiines identify potential hosts through the use of specialized antennal receptors that are extremely sensitive to their host’s pheromones, indicating great potential for biological control. The phylogenetic relationships within Phasiinae were explored using sequences from CAD, 28S, and three novel nuclear coding genes (LGL, MCS, and MAC). A total of 122 taxa were included in the analyses, representing 67 genera. Maximum likelihood and Bayesian inference methods were employed to reconstruct phylogenetic relationships in separate analyses of each gene and in a combined dataset. Phylogenetic reconstructions generally supported recent morphological classifications based on oviposition strategies and postabdomen characters. All tribes in Phasiinae were recovered as monophyletic or could become so with minor changes to current classification schemes. The Tachinidae were recovered as a monophyletic family, and the monophyly of the subfamilies Tachininae, Exoristinae, and Phasiinae was resolved with varying levels of statistical support. Dexiinae were paraphyletic. This phylogeny provides the first molecular support for the following hypothesized taxonomic relationships: 1) Removing Litophasia from Catharosiini, 2) Transferring Euclytia, Eliozeta, Ectophasia, and Clytiomya from Phasiini to Gymnosomatini, 3) Including Strongygaster and Rondaniooestrus in Phasiinae, 4) Placing Rondaniooestrus in Strongygastrini, and 5) Including Litophasia, Euthera, and Epigrimyia in Dexiinae.