Monophyly, composition, and relationships within Saturniinae (Lepidoptera: Saturniidae): Evidence from two nuclear genes

Abstract

The approximately 1500 species of Saturniidae or wild silk moths, which include some of the largest of all lepidopterans, have provided important model systems for studies of ecology, developmental genetics, and behavior. Such studies would benefit from a robust comparative framework, but there has been little phylogenetic analysis of this family. To address this, we use nuclear gene sequences to test hypotheses about the monophyly and internal relationships of the large and geographically widespread subfamily Saturniinae (63 genera, 644 spp.). Extending our previous examination of the genera of Attacini, we analyze coding sequence from elongation factor-1α (1240 nt) and dopa decarboxylase (typically 1051 nt) in 64 species representing four of five tribes in Saturniinae, 11 of 16 genera in Saturniini, and outgroups in Saturniidae and other bombycoids. The results support a recent postulate that Saturniinae, largely Oriental and Palearctic in distribution, should include the African Micragonini. The alternative that Micragonini or some subgroup thereof constitute its own subfamily (previously called Ludiinae) is shown to result in a paraphyletic Saturniinae. Micragonini group strongly with the tribe Bunaeini, also African. Monophyly for Saturniinae, including Micragonini, is strongly supported, as is a basal split between Attacini + Saturniini and Bunaeini + Micragonini. As a consequence, a postulated affinity to the African tribes of two Madagascan endemic Saturniini, thus rendering Saturniini paraphyletic, is rejected. However, there is no strong evidence either way on monophyly of Saturniini versus paraphyly with respect to the clearly monophyletic Attacini (atlas moths and relatives). This result reflects generally weak resolution of deeper divergences in Saturnini. Several lower-level groupings within Saturniini are strongly corroborated, including the tailed-hindwinged 'moon moths' (Argema, Actias, Graellsia) that specialize on resinous hostplants, and Saturnia sensu lato, a consolidation of eight small, former genera.