Phylogenomics resolves major relationships and reveals significant diversification rate shifts in the evolution of silk moths and relatives

Abstract Background The silkmoths and their relatives constitute the ecologically and taxonomically diverse superfamily Bombycoidea, which includes some of the most charismatic species of Lepidoptera. Despite displaying some of the most spectacular forms and ecological traits among insects, relatively little attention has been given to understanding their evolution and the drivers of their diversity. Results To begin to address this problem, we created a new Bombycoidea-specific Anchored Hybrid Enrichment (AHE) probe set and sampled up to 571 loci for 117 taxa across all major lineages of the Bombycoidea, producing a well-supported phylogeny. The tree was overall consistent with prior morphological and molecular studies, although some taxa (e.g., Arotros Schaus) were misplaced in the Bombycidae and here formally transferred to Apatelodidae. We identified important evolutionary patterns (e.g., morphology, biogeography, and differences in speciation and extinction), and our analysis of diversification rates highlights the stark increases that exist within the Sphingidae (hawkmoths) and Saturniidae (wild silkmoths). Conclusions We postulate that these rate shifts are due to the well-documented bat-moth “arms race” and differences in selective pressures from insectivorous bats. The study establishes a backbone for future evolutionary, comparative, and taxonomic studies, and presents a modified DNA extraction protocol that allows Lepidoptera specimens to be readily sequenced from pinned natural history collections, succeeding in samples up to 30 years old. Our research highlights the flexibility of AHE to generate genomic data from a wide range of museum specimens, both age and preservation method, and will allow researchers to tap into the wealth of biological data residing in natural history collections around the globe.