A molecular phylogeny for Yponomeutoidea (Lepidoptera: Ditrysia): new light on phylogenetic relationships and insect-plant interactions in basal ditrysian Lepidoptera

Yponomeutoidea represent one of the major radiations in the basal ditrysian Lepidoptera. Yponomeutoidea are especially important for tracing the early evolutionary history of Lepidoptera-plant interactions because they are one of the earliest groups to evolve external feeding (Powell et al., 1998) and to extensively colonize herbs as well as shrubs and trees (Grimaldi and Engel, 2005). Despite its importance to tracing the early evolution of Lepidoptera, the superfamily Yponomeutoidea has been neglected by systematists, and its biodiversity and phylogeny remain poorly understood. Due to the lack of phylogenetic approaches, several researchers have suggested different definitions of Yponomeutoidea which are still in contention. Disagreements on the phylogeny of Yponomeutoidea in turn have helped to obscure inter-relationships of the basal lepidopteran groups and hindered the testing of evolutionary hypotheses on which these bear. To improve the systematic resolution of Yponomeutoidea, phylogenetic analyses based on 5 to 26 nuclear genes were conducted. The resulting trees were dated by relaxed molecular clock methods with fossil calibration constraints. The molecular approaches suggested a phylogeny of Yponomeutoidea which is different from other morphology-based hypotheses. The results provide new insights on the circumscription of Yponomeutoidea and on the evolution of host plant associations in the basal ditrysian Lepidoptera.