Butterflies and moths (Lepidoptera) are one of the major superradiations of insects, comprising nearly 160,000 described extant species. As herbivores, pollinators, and prey, Lepidoptera play a fundamental role in almost every terrestrial ecosystem. Lepidoptera are also indicators of environmental change and serve as models for research on mimicry and genetics. They have been central to the development of coevolutionary hypotheses, such as butterflies with flowering plants and moths’ evolutionary arms race with echolocating bats. However, these hypotheses have not been rigorously tested, because a robust lepidopteran phylogeny and timing of evolutionary novelties are lacking. To address these issues, we inferred a comprehensive phylogeny of Lepidoptera, using the largest dataset assembled for the order (2,098 orthologous protein-coding genes from transcriptomes of 186 species, representing nearly all superfamilies), and dated it with carefully evaluated synapomorphy-based fossils. The oldest members of the Lepidoptera crown group appeared in the Late Carboniferous (∼300 Ma) and fed on nonvascular land plants. Lepidoptera evolved the tube-like proboscis in the Middle Triassic (∼241 Ma), which allowed them to acquire nectar from flowering plants. This morphological innovation, along with other traits, likely promoted the extraordinary diversification of superfamily-level lepidopteran crown groups. The ancestor of butterflies was likely nocturnal, and our results indicate that butterflies became day-flying in the Late Cretaceous (∼98 Ma). Moth hearing organs arose multiple times before the evolutionary arms race between moths and bats, perhaps initially detecting a wide range of sound frequencies before being co-opted to specifically detect bat sonar. Our study provides an essential framework for future comparative studies on butterfly and moth evolution.

Gracillariidae are one of the most diverse families of internally feeding insects, and many species are economically important. Study of this family has been hampered by lack of a robust and comprehensive phylogeny. In the present paper, we sequenced up to 22 genes in 96 gracillariid species, representing all previously recognized subfamilies and genus groups, plus 20 outgroups representing other families and superfamilies. Following objective identification and removal of two rogue taxa, two datasets were constructed: dataset 1, which included 12 loci totalling 9927 bp for 94 taxa, and dataset 2, which supplemented dataset 1 with 10 additional loci for 10 taxa, for a total of 22 loci and 16 167 bp. Maximum likelihood analyses strongly supported the monophyly of Gracillariidae and most previously recognized subfamilies and genus groups. On this basis, we propose a new classification consisting of eight subfamilies, four of which are newly recognized or resurrected: Acrocercopinae Kawahara & Ohshima subfam. n.; Gracillariinae Stainton; Lithocolletinae Stainton; Marmarinae Kawahara & Ohshima subfam. n.; Oecophyllembiinae Réal & Balachowsky; Parornichinae Kawahara & Ohshima subfam. n.; Ornixolinae Kuznetzov & Baryshnikova stat. rev.; and Phyllocnistinae Zeller. The subfamily Gracillariinae is restricted to the monophyletic group comprising Gracillaria Haworth and closely related genera. We also formally transfer Acrocercops scriptulata Meyrick to Ornixolinae and use the name Diphtheroptila Vári, creating Diphtheroptila scriptulata comb. n. An exploratory mapping of larval host‐use traits on the phylogeny shows strong conservation of modes of leaf mining but much higher lability of associations with host plant orders and families, suggesting that host shifts could play a significant role in gracillariid diversification. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:942814A2-DE66-41D4-8AB6-FF0B18C87EDB.

Butterflies are a diverse and charismatic insect group that are thought to have evolved with plants and dispersed throughout the world in response to key geological events. However, these hypotheses have not been extensively tested because a comprehensive phylogenetic framework and datasets for butterfly larval hosts and global distributions are lacking. We sequenced 391 genes from nearly 2,300 butterfly species, sampled from 90 countries and 28 specimen collections, to reconstruct a new phylogenomic tree of butterflies representing 92% of all genera. Our phylogeny has strong support for nearly all nodes and demonstrates that at least 36 butterfly tribes require reclassification. Divergence time analyses imply an origin ~100 million years ago for butterflies and indicate that all but one family were present before the K/Pg extinction event. We aggregated larval host datasets and global distribution records and found that butterflies are likely to have first fed on Fabaceae and originated in what is now the Americas. Soon after the Cretaceous Thermal Maximum, butterflies crossed Beringia and diversified in the Palaeotropics. Our results also reveal that most butterfly species are specialists that feed on only one larval host plant family. However, generalist butterflies that consume two or more plant families usually feed on closely related plants.

Insect silk is a versatile biomaterial. Lepidoptera and Trichoptera display some of the most diverse uses of silk, with varying strength, adhesive qualities, and elastic properties. Silk fibroin genes are long (>20 Kbp), with many repetitive motifs that make them challenging to sequence.Most research thus far has focused on conserved N-and C-terminal regions of fibroin genes because a full comparison of repetitive regions across taxa has not been possible. Using the PacBio Sequel II system and SMRT sequencing, we generated high fidelity (HiFi) long-read genomic and transcriptomic sequences for the Indianmeal moth (Plodia interpunctella) and genomic sequences for the caddisfly Eubasilissa regina. Both genomes were highly contiguous (N50 = 9.7 Mbp/32.4 Mbp, L50 = 13/11) and complete (BUSCO complete = 99.3%/95.2%), with complete and contiguous recovery of silk heavy fibroin gene sequences. We show that HiFi long-read sequencing is helpful for understanding genes with long, repetitive regions.