Phylogenetic relationships of the euchromiine tiger moths (Erebidae: Arctiinae: Arctiini)

Tiger moths are known for their colorful adult forms, and for their larval association with toxic host plants. Larvae sequester these toxins, often storing these chemicals throughout their lives as a chemical defense. These moths are often aposematic, warning predators of their toxicity. Lack of phylogenetic information hampers efforts to study the evolution of aposematic adult forms within the Arctiinae. One lineage, the euchromiines, are precise Müllerian mimics of wasps and other noxious insects. Recent studies have demonstrated that a core set of genera comprise a monophyletic Euchromiina with respect to sister clades Ctenuchina and Phageopterina, but strong support for group’s monophyly is lacking probably due to a paucity of sampled genes appropriate for examining relationships at this taxonomic level. I examined the monophyly of the Euchromiina and phylogenetic relationships within the subtribe. I used seven genes: DI, DII, EF1a, GAPDH, IDH, RPS5 and wgl, which have been demonstrated to be useful for phylogenetic studies Lepidoptera. We found that the Euchromiina is monophyletic with the respect to the Ctenuchina and Phagopterina with high support. There is also evidence for well-defined monophyletic Ctenuchina and a paraphyletic Phagopterina.  Results also show that several large genera (i.e. Cosmosoma, Isanthrene, and Sphecosoma) are artificial assemblages, and should be split into multiple genera. Our results provide a stable framework for the euchromiines, which will facilitate further revisionary work and studies involving the evolution of mimetic traits.