Tiger Swallowtail Genome Reveals Mechanisms for Speciation and Caterpillar Chemical Defense

Phylogenetic and Comparative Genomics Study of Papilionidae Based on Mitochondrial Genomes

Most species of Papilionidae are large and beautiful ornamental butterflies. They are recognized as model organisms in ecology, evolutionary biology, genetics, and conservation biology but present numerous unresolved phylogenetic problems. Complete mitochondrial genomes (mitogenomes) have been widely used in phylogenetic studies of butterflies, but mitogenome knowledge within the family Papilionidae is limited, and its phylogeny is far from resolved. In this study, we first report the mitogenome of Byasa confusa from the subfamily Papilioninae of Papilionidae. The mitogenome of B. confusa is 15,135 bp in length and contains 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and an AT-rich control region (CR), closely mirroring the genomic structure observed in related butterfly species. Comparative analysis of 77 Papilionidae mitogenomes shows gene composition and order to be identical to that of an ancestral insect, and the AT bias, Ka/Ks, and relative synonymous codon usage (RSCU) are all consistent with that of other reported butterfly mitogenomes. We conducted phylogenetic analyses using maximum-likelihood (ML) and Bayesian-inference (BI) methods, with 77 Papilionidae species as ingroups and two species of Nymphalidae and Lycaenidae as outgroups. The phylogenetic analysis indicated that B. confusa were clustered within Byasa. The phylogenetic trees show the monophyly of the subfamily Papilioninae and the tribes Leptocircini, Papilionini, and Troidini. The data supported the following relationships in tribe level on Papilioninae: (((Troidini + Papilionini) + Teinopalpini) + Leptocircini). The divergence time analysis suggests that Papilionidae originated in the late Creataceous. Overall, utilizing the largest number of Papilionidae mitogenomes sequenced to date, with the current first exploration in a phylogenetic analysis on Papilionidae (including four subfamilies), this study comprehensively reveals the mitogenome characteristics and mitogenome-based phylogeny, providing information for further studies on the mitogenome, phylogeny, evolution, and taxonomic revision of the Papilionidae family.

Complete mitochondrial genome data and phylogenetic analysis of Papilio macilentus Janson, 1877 (Lepidoptera: Papilionoidea: Papilionidae)

In the present study, the complete mitochondrial genome (mitogenome) of the Papilio macilentus (Lepidoptera: Papilionoidea: Papilionidae) was sequenced by next-generation sequencing method. The mitochondrial genome is a circular DNA molecule of 15,264 bp in size with 80.7% AT content, including 37 genes (13 protein-coding genes, 2 rRNA genes, and 22 tRNA genes), and a long non-coding region (Control region). All protein-coding genes are initiated by ATN codons, and terminated with TAA, TAG, or single T. All tRNAs can be folded into common clover leaf secondary structure, except trn-S1. Phylogenetic analyses based on 13 protein-coding genes and 2 rRNA genes using maximum likelihood and Bayesian inference confirmed that P. macilentus and Papilio memnon are clustered into a clade, and revealed the relationships between Papilionini, Troidini, Teinopaippini and Leptocircini.

What one genus of showy moths can say about migration, adaptation, and wing pattern

The Ornate Moth, Utetheisa ornatrix, has served as a model species in chemical ecology studies for decades. Like in the widely publicized stories of the Monarch and other milkweed butterflies, the Ornate Moth and its relatives are tropical insects colonizing whole continents assisted by their chemical defenses. With the recent advances in genomic techniques and evo-devo research, it is becoming a model for studies in other areas, from wing pattern development to phylogeography, from toxicology to epigenetics. We used a genomic approach to learn about Utetheisa's evolution, detoxification, dispersal abilities, and wing pattern diversity. We present an evolutionary genomic analysis of the worldwide genus Utetheisa, then focusing on U. ornatrix. Our reference genome of U. ornatrix reveals gene duplications in the regions possibly associated with detoxification abilities, which allows them to feed on toxic food plants. Finally, comparative genomic analysis of over 100 U. ornatrix specimens from the museum with apparent differences in wing patterns suggest the potential roles of cortex and lim3 genes in wing pattern formation of Lepidoptera and the utility of museum-preserved collection specimens for wing pattern research.

A draft reference genome assembly of the Pipevine Swallowtail butterfly, Battus philenor hirsuta

The California Pipevine Swallowtail Butterfly, Battus philenor hirsuta, and its host plant, the California Pipevine or Dutchman's Pipe, Aristolochia californica Torr., are an important California endemic species pair. While this species pair is an ideal system to study co-evolution, genomic resources for both are lacking. Here, we report a new, chromosome-level assembly of B. philenor hirsuta as part of the California Conservation Genomics Project (CCGP). Following the sequencing and assembly strategy of the CCGP, we used Pacific Biosciences HiFi long reads and Hi-C chromatin proximity sequencing technology to produce a de novo assembled genome. Our genome assembly, the first for any species in the genus, contains 109 scaffolds spanning 443 mega base (Mb) pairs, with a contig N50 of 14.6 Mb, a scaffold N50 of 15.2 Mb, and BUSCO complete score of 98.9%. In combination with the forthcoming A. californica reference genome, the B. philenor hirsuta genome will be a powerful tool for documenting landscape genomic diversity and plant-insect co-evolution in a rapidly changing California landscape.

Base Composition, Codon Usage, and Patterns of Gene Sequence Evolution in Butterflies

Coding sequence evolution is influenced by both natural selection and neutral evolutionary forces. In many species, the effects of mutation bias, codon usage, and GC-biased gene conversion (gBGC) on gene sequence evolution have not been detailed. Quantification of how these forces shape substitution patterns is therefore necessary to understand the strength and direction of natural selection. Here, we used comparative genomics to investigate the association between base composition and codon usage bias on gene sequence evolution in butterflies and moths (Lepidoptera), including an in-depth analysis of underlying patterns and processes in one species, Leptidea sinapis. The data revealed significant G/C to A/T substitution bias at third codon position with some variation in the strength among different butterfly lineages. However, the substitution bias was lower than expected from previously estimated mutation rate ratios, partly due to the influence of gBGC. We found that A/T-ending codons were overrepresented in most species, but there was a positive association between the magnitude of codon usage bias and GC-content in third codon positions. In addition, the tRNA-gene population in L. sinapis showed higher GC-content at third codon positions compared to coding sequences in general and less overrepresentation of A/T-ending codons. There was an inverse relationship between synonymous substitutions and codon usage bias indicating selection on synonymous sites. We conclude that the evolutionary rate in Lepidoptera is affected by a complex interaction between underlying G/C -> A/T mutation bias and partly counteracting fixation biases, predominantly conferred by overall purifying selection, gBGC, and selection on codon usage.

Genome-Wide Analysis of Odorant and Gustatory Receptors in Six Papilio Butterflies (Lepidoptera: Papilionidae)

The chemical interactions of insects and host plants are shaping the evolution of chemosensory receptor gene families. However, the correlation between host range and chemoreceptor gene repertoire sizes is still elusive in Papilionidae. Here, we addressed the issue of whether host plant diversities are correlated with the expansions of odorant (ORs) or gustatory (GRs) receptors in six Papilio butterflies. By combining genomics, transcriptomics and bioinformatics approaches, 381 ORs and 328 GRs were annotated in the genomes of a generalist P. glaucus and five specialists, P. xuthus, P. polytes, P. memnon, P. machaon and P. dardanus. Orthologous ORs or GRs in Papilio had highly conserved gene structure. Five Papilio specialists exhibited a similar frequency of intron lengths for ORs or GRs, but which was different from those in the generalist. Phylogenetic analysis revealed 60 orthologous OR groups, 45 of which shared one-to-one relationships. Such a single gene in each butterfly also occurred in 26 GR groups. Intriguingly, bitter GRs had fewer introns than other GRs and clustered into a large clade. Focusing on the two chemoreceptor gene families in P. xuthus, most PxutORs (52/58) were expressed in antennae and 31 genes in reproductive tissues. Eleven out of 28 foretarsus-expressed PxutGRs were female-biased genes, as strong candidates for sensing oviposition stimulants. These results indicate that the host range may not shape the large-scale expansions of ORs and GRs in Papilio butterflies and identify important molecular targets involved in olfaction, oviposition or reproduction in P. xuthus.

Taxonomic changes suggested by the genomic analysis of Hesperiidae (Lepidoptera)

Our expanded efforts in genomic sequencing to cover additional skipper butterfly (Lepidoptera: Hesperiidae) species and populations, including primary type specimens, call for taxonomic changes to restore monophyly and correct misidentifications by moving taxa between genera and proposing new names. Reconciliation between phenotypic characters and genomic trees suggests three new tribes, two new subtribes, 23 new genera, 17 new subgenera and 10 new species that are proposed here: Psolosini Grishin, new tribe (type genus Psolos Staudinger, 1889), Ismini Grishin, new tribe (type genus Isma Distant, 1886), Eetionini Grishin, new tribe (type genus Eetion de Nicéville, 1895), Orphina Grishin, new subtribe (type genus Orphe Godman, 1901), Carystoidina Grishin, new subtribe (type genus Carystoides Godman, 1901), Fulvatis Grishin, new genus (type species Telegonus fulvius Plötz, 1882), Adina Grishin, new genus (type species Nascus adrastor Mabille and Boullet, 1912), Ornilius Grishin, new genus (type species Ornilius rotundus Grishin, new species), Tolius Grishin, new genus (type species Antigonus tolimus Plötz, 1884), Lennia Grishin, new genus (type species Leona lena Evans, 1937), Trida Grishin, new genus (type species Cyclopides barberae Trimen, 1873), Noxys Grishin, new genus (type species Oxynthes viricuculla Hayward, 1951), Gracilata Grishin, new genus (type species Enosis quadrinotata Mabille, 1889), Hermio Grishin, new genus (type species Falga ? hermione Schaus, 1913), Eutus Grishin, new genus (type species Cobalus rastaca Schaus, 1902), Gufa Grishin, new genus (type species Phlebodes gulala Schaus, 1902), Godmia Grishin, new genus (type species Euroto chlorocephala Godman, 1900), Rhomba Grishin, new genus (type species Eutychide gertschi Bell, 1937), Rectava Grishin, new genus (type species Megistias ignarus Bell, 1932), Contrastia Grishin, new genus (type species Hesperia distigma Plötz, 1882), Mit Grishin, new genus (type species Mnasitheus badius Bell, 1930), Picova Grishin, new genus (type species Vorates steinbachi Bell, 1930), Lattus Grishin, new genus (type species Eutocus arabupuana Bell, 1932), Gubrus Grishin, new genus (type species Vehilius lugubris Lindsey, 1925), Koria Grishin, new genus (type species Hesperia kora Hewitson, 1877), Corta Grishin, new genus (type species Eutychide lycortas Godman, 1900), Calvetta Grishin, new genus (type species Hesperia calvina Hewitson, 1866), Oz Grishin, new genus (type species Astictopterus ozias Hewitson, 1878), Praxa Grishin, new subgenus (type species Nascus prax Evans, 1952), Bron Grishin, new subgenus (type species Papilio broteas Cramer, 1780), Turis Grishin, new subgenus (type species Pyrgus (Scelothrix) veturius Plötz, 1884), Tiges Grishin, new subgenus (type species Antigonus liborius Plötz, 1884), Ocrypta Grishin, new subgenus (type species Notocrypta caerulea Evans, 1928), Tixe Grishin, new subgenus (type species Cobalus quadrata Herrich-Schäffer, 1869), Nycea Grishin, new subgenus (type species Pamphila hycsos Mabille, 1891), Nausia Grishin, new subgenus (type species Oenus [sic] nausiphanes Schaus, 1913), Flor Grishin, new subgenus (type species Stomyles florus Godman, 1900), Geia Grishin, new subgenus (type species Pamphila geisa Möschler, 1879), Rotundia Grishin, new subgenus (type species Enosis schausi Mielke and Casagrande, 2002), Volus Grishin, new subgenus (type species Eutocus volasus Godman, 1901), Pseudopapias Grishin, new subgenus (type species Papias tristissimus Schaus, 1902), Septia Grishin, new subgenus (type species Justinia septa Evans, 1955), Brasta Grishin, new subgenus (type species Lychnuchus brasta Evans, 1955), Bina Grishin, new subgenus (type species Cobalus gabina Godman, 1900), Balma Grishin, new subgenus (type species Carystoides balza Evans, 1955), Ornilius rotundus Grishin, new species (type locality in Brazil: Santa Catarina), Salantoia metallica Grishin, new species (type locality in Guyana: Acarai Mts.), Dyscophellus australis Grishin, new species (type locality in Paraguay: Sapucay), Dyscophellus basialbus Grishin, new species (type locality in Brazil: Rondônia), Telegonus subflavus Grishin, new species (type locality in Ecuador: Riobamba), Decinea colombiana Grishin, new species (type locality in Colombia: Bogota), Lerema lucius Grishin, new species (type locality in Panama: Colón), Cynea rope Grishin, new species (type locality in Nicaragua: Chontales), Lerodea sonex Grishin, new species (type locality in Peru: Cuzco), and Metiscus goth Grishin, new species (type locality in Costa Rica). Lectotypes are designated for the following 17 taxa: Telegonus gildo Mabille, 1888, Netrocoryne damias Plötz, 1882, Telegonus erythras Mabille, 1888, Telegonus galesus Mabille, 1888, Eudamus cretellus Herrich-Schäffer, 1869, Leucochitonea chaeremon Mabille, 1891, Antigonus aura Plötz, 1884, Pamphila voranus Mabille, 1891, Hesperia pupillus Plötz, 1882, Cobalus lumina Herrich-Schäffer, 1869, Cobalus stigmula Mabille, 1891, Megistias isus Godman, 1900, Cobalopsis latonia Schaus, 1913, Pamphila nubila Mabille, 1891, Metiscus atheas Godman, 1900, Mnasalcas amatala Schaus, 1902, and Hesperia ina Plötz, 1882. The lectotype of Hesperia infuscata Plötz, 1882 is invalid because it does not agree with the original description and illustration by Plötz, is not from the locality listed in the original description, and therefore is not a syntype. Neotypes are designated for the following five taxa: Telegonus corentinus Plötz, 1882, Hesperia dido Plötz, 1882, Hesperia distigma Plötz, 1882, Hesperia infuscata Plötz, 1882, and Hesperia pruinosa Plötz, 1882. As a result, the following five taxa are junior objective synonyms: Telegonus diophorus Möschler, 1883 of Telegonus corentinus Plötz, 1882, Pamphila puxillius Mabille, 1891 of Hesperia pupillus Plötz, 1882, Cobalus stigmula Mabille, 1891 of Hesperia distigma Plötz, 1882, Mnasalcas amatala Schaus, 1902 of Hesperia infuscata Plötz, 1882, and Hesperia pruinosa Plötz, 1882 of Hesperia uza Hewitson, 1877. Morys valerius valda Evans, 1955 is fixed as the type species of Morys Godman, 1900, and Pamphila compta Butler, 1877 is reaffirmed as the type species of Euroto Godman, 1900. Furthermore, the following taxonomic changes are suggested. Prosopalpus Holland, 1896, Lepella Evans, 1937, and Creteus de Nicéville, 1895 are placed in Aeromachini Tutt, 1906. Triskelionia Larsen and Congdon, 2011 is transferred from Celaenorrhinini Swinhoe, 1912 to Tagiadini Mabille, 1878. Kobelana Larsen and Collins, 2013 is transferred from Tagiadini Mabille, 1878 to Celaenorrhinini Swinhoe, 1912. The following nine genus-group names are resurrected from synonymy and treated as valid genera: Abaratha Moore, 1881 (not in Caprona Wallengren, 1857), Bibla Mabille, 1904 (not in Taractrocera Butler, 1870), Kerana Distant, 1886 and Tamela Swinhoe, 1913 (not in Ancistroides Butler, 1874), Metrocles Godman, 1900 (not in Metron Godman, 1900), Alerema Hayward, 1942 (not in Tigasis Godman, 1900), Metiscus Godman, 1900 (not in Enosis Mabille, 1889), Vistigma Hayward, 1939 (not in Phlebodes Hübner, [1819]), and Mnasalcas Godman, 1900 (not in Mnasitheus Godman, 1900). The genus-group names Daimio Murray, 1875 and Pterygospidea Wallengren, 1857 are resurrected from synonymy and treated as valid subgenera of Tagiades Hübner, [1819]. We confirm Apallaga Strand, 1911 as a valid genus. The following 24 genera are placed as subgenera, new status: Pseudonascus Austin, 2008 of Nascus Watson, 1893; Albiphasma Huang, Chiba, Wang and Fan, 2016 of Pintara Evans, 1932; Ctenoptilum de Nicéville, 1890 of Tapena Moore, [1881]; Odontoptilum de Nicéville, 1890 of Abaratha Moore, 1881; Caprona Wallengren, 1857 of Abantis Hopffer, 1855; Timochreon Godman and Salvin, 1896 of Zopyrion Godman and Salvin, 1896; Pulchroptera Hou, Fan and Chiba, 2021 of Heteropterus Duméril, 1806; Stimula de Nicéville, 1898 of Koruthaialos Watson, 1893; Udaspes Moore, [1881] and Notocrypta de Nicéville, 1889 of Ancistroides Butler, 1874; Cravera de Jong, 1983 of Xeniades Godman, 1900; Cobaloides Hayward, 1939 of Oligoria Scudder, 1872; Saniba O. Mielke and Casagrande, 2003 of Psoralis Mabille, 1904; Quinta Evans, 1955 of Cynea Evans, 1955; Styriodes Schaus, 1913 and Remella Hemming, 1939 of Mnasicles Godman, 1901; Repens Evans, 1955 of Eprius Godman, 1901; Morys Godman, 1900 of Lerema Scudder, 1872; Enosis Mabille, 1889 of Lychnuchus Hübner, [1831]; Penicula Evans, 1955 of Vistigma Hayward, 1939; Mnasinous Godman, 1900 of Methionopsis Godman, 1901; and Moeros Evans, 1955, Argon Evans, 1955, and Synale Mabille, 1904 of Carystus Hübner, [1819]. The following 20 genera are treated as junior subjective synonyms: Leucochitonea Wallengren, 1857 of Abantis Hopffer, 1855; Sapaea Plötz, 1879 and Netrobalane Mabille, 1903 of Caprona Wallengren, 1857; Parasovia Devyatkin, 1996 of Sebastonyma Watson, 1893; Pemara Eliot, 1978 of Oerane Elwes and Edwards, 1897; Ankola Evans, 1937 of Pardaleodes Butler, 1870; Arotis Mabille, 1904 of Mnaseas Godman, 1901; Chalcone Evans, 1955, Hansa Evans, 1955, and Propertius Evans, 1955 of Metrocles Godman, 1900; Jongiana O. Mielke and Casagrande, 2002 of Cobaloides Hayward, 1939; Pamba Evans, 1955 of Psoralis Mabille, 1904; Brownus Grishin, 2019 of Styriodes Schaus, 1913; Mnasilus Godman, 1900 of Papias Godman, 1900; Sucova Evans, 1955 of Mnasitheus Godman, 1900; Pyrrhocalles Mabille, 1904 and Asbolis Mabille, 1904 of Choranthus Scudder, 1872; Miltomiges Mabille, 1903 of Methionopsis Godman, 1901; Sacrator Evans, 1955 of Thracides Hübner, [1819]; and Lychnuchoides Godman, 1901 of Perichares Scudder, 1872. Arunena Swinhoe, 1919 is a junior subjective synonym of Stimula de Nicéville, 1898 (not of Koruthaialos Watson, 1893). The following 27 names are species-level taxa (some in new combinations) reinstated from synonymy: Salantoia gildo (Mabille, 1888) (not Salatis cebrenus (Cramer, 1777)), Bungalotis corentinus (Plötz, 1882) (not Bungalotis midas (Cramer, 1775)), Telegonus cretellus (Herrich-Schäffer, 1869) (not Telegonus cassander (Fabricius, 1793)), Santa palica (Mabille, 1888) (not Chiothion asychis (Stoll, 1780)), Camptopleura cincta Mabille and Boullet, 1917 (not Camptopleura auxo (Möschler, 1879)), Camptopleura orsus (Mabille, 1889) (not Nisoniades mimas (Cramer, 1775)), Metron voranus (Mabille, 1891) and Metron fasciata (Möschler, 1877) (not Metron zimra (Hewitson, 1877)), Limochores catahorma (Dyar, 1916) (not Limochores pupillus (Plötz, 1882)), Pares viridiceps (Mabille, 1889) (not Thoon modius (Mabille, 1889)), Tigasis wellingi (Freeman, 1969) (not Tigasis arita (Schaus, 1902)), Rectava sobrinus (Schaus, 1902) (not Papias phainis Godman, 1900), Nastra subsordida (Mabille, 1891) (not Adlerodea asema (Mabille, 1891), previously in Eutychide Godman, 1900), Lerema pattenii Scudder, 1872 (not Lerema accius (J. E. Smith, 1797)), Lerema (Morys) ancus (Möschler, 1879) (not Cymaenes tripunctus theogenis (Capronnier, 1874)), Cobalopsis zetus (Bell, 1942) (not Cobalopsis nero (Herrich-Schäffer, 1869)), Lerema (Geia) etelka (Schaus, 1902) (not Lerema (Geia) geisa (Möschler, 1879), previously in Morys Godman, 1900), Cymaenes isus (Godman, 1900) (not Cymaenes trebius (Mabille, 1891)), Vehilius labdacus (Godman, 1900) (not Vehilius inca (Scudder, 1872)), Papias amyrna (Mabille, 1891) (not Papias allubita (Butler, 1877), previously in Mnasilus Godman, 1900), Papias integra (Mabille, 1891) (not Papias subcostulata (Herrich-Schäffer, 1870)), Metiscus atheas Godman, 1900 (not Hesperia achelous Plötz, 1882), Dion agassus (Mabille, 1891) (not Dion uza (Hewitson, 1877), previously in Enosis Mabille, 1889), Picova incompta (Hayward, 1942) (not Lerema (Morys) micythus (Godman, 1900), previously in Morys Godman, 1900), Lucida melitaea (Draudt, 1923) (not Lucida lucia (Capronnier, 1874)), Methionopsis modestus Godman, 1901 (not Methionopsis ina (Plötz, 1882)), and Thargella (Volus) volasus (Godman, 1901) (not Eutocus facilis (Plötz, 1884)). The following 57 taxa are elevated from subspecies to species, new status (some in new combinations): Dyscophellus doriscus (Hewitson, 1867) (not Dyscophellus porcius (C. Felder and R. Felder, 1862), Phocides vida (A. Butler, 1872) (not Phocides urania (Westwood, 1852)), Tagiades (Daimio) ceylonica Evans, 1932 (not Tagiades litigiosa Möschler, 1878), Tagiades (Daimio) tubulus Fruhstorfer, 1910 (not Tagiades sambavana Elwes and Edwards, 1897), Tagiades (Daimio) kina Evans, 1934, Tagiades (Daimio) sheba Evans, 1934, Tagiades (Daimio) martinus Plötz, 1884, Tagiades (Daimio) sem Mabille, 1883, and Tagiades (Daimio) neira Plötz, 1885 (not Tagiades trebellius (Hopffer, 1874)), Tagiades (Daimio) korela Mabille, 1891 and Tagiades (Daimio) presbyter Butler, 1882 (not Tagiades nestus (C. Felder, 1860)), Tagiades obscurus Mabille, 1876, Tagiades ravi (Moore, [1866]), Tagiades atticus (Fabricius, 1793), Tagiades titus Plötz, 1884, Tagiades janetta Butler, 1870, Tagiades inconspicua Rothschild, 1915, and Tagiades hovia Swinhoe, 1904 (not Tagiades japetus (Stoll, [1781])), Tagiades silvia Evans, 1934 and Tagiades elegans Mabille, 1877 (not Tagiades gana (Moore, [1866])), Tapena bornea Evans, 1941 and Tapena minuscula Elwes and Edwards, 1897 (not Tapena thwaitesi Moore, [1881]), Darpa dealbata (Distant, 1886) (not Darpa pteria (Hewitson, 1868)), Perus manx (Evans, 1953) (not Perus minor (Schaus, 1902)), Canesia pallida (Röber, 1925) (not Carrhenes canescens (R. Felder, 1869)), Carrhenes conia Evans, 1953 (not Carrhenes fuscescens (Mabille, 1891)), Anisochoria extincta Hayward, 1933 and Anisochoria polysticta Mabille, 1876 (not Anisochoria pedaliodina (Butler, 1870)), Anisochoria verda Evans, 1953 (not Anisochoria minorella Mabille, 1898), Bralus alco (Evans, 1953) (not Bralus albida (Mabille, 1888)), Ephyriades jamaicensis (Möschler, 1879) (not Ephyriades brunnea (Herrich-Schäffer, 1865)), Koruthaialos (Stimula) frena Evans, 1949 (not Koruthaialos focula (Plötz, 1882)), Euphyes kiowah (Reakirt, 1866) (not Euphyes vestris (Boisduval, 1852)), Mnaseas inca Bell, 1930 (not Mnaseas bicolor (Mabille, 1889)), Metron hypochlora (Draudt, 1923) (not Metrocles schrottkyi (Giacomelli, 1911), previously in Metron Godman, 1900), Decinea huasteca (H. Freeman, 1969), Decinea denta Evans, 1955, and Decinea antus (Mabille, 1895) (not Decinea decinea (Hewitson, 1876)), Xeniades pteras Godman, 1900 (not Xeniades chalestra (Hewitson, 1866)), Xeniades difficilis Draudt, 1923 (not Xeniades orchamus (Cramer, 1777)), Xeniades hermoda (Hewitson, 1870) (not Tisias quadrata (Herrich-Schäffer, 1869)), Hermio vina (Evans, 1955) (not Hermio hermione (Schaus, 1913), previously in Lento Evans, 1955), Cymaenes loxa Evans, 1955, (not Cymaenes laureolus (Schaus, 1913)), Niconiades peri (Evans, 1955) (not Rhinthon bajula (Schaus, 1902), previously in Neoxeniades Hayward, 1938), Gallio danius (Bell, 1941) (not Vehilius seriatus (Mabille, 1891)), Gallio massarus (E. Bell, 1940) (not Gallio garima (Schaus, 1902) previously in Tigasis Godman, 1900), Cymaenes edata (Plötz, 1882), Cymaenes miqua (Dyar, 1913) and Cymaenes aequatoria (Hayward, 1940) (not Cymaenes odilia (Burmeister, 1878)), Lychnuchus (Enosis) demon (Evans, 1955) (not Lychnuchus (Enosis) immaculata (Hewitson, 1868), previously in Enosis Mabille, 1889), Naevolus naevus Evans, 1955 (not Naevolus orius (Mabille, 1883)), Lucida scopas (Mabille, 1891), Lucida oebasus (Godman, 1900), and Lucida leopardus (Weeks, 1901) (not Lucida lucia (Capronnier, 1874)), Corticea schwarzi (E. Bell, 1941) and Corticea sylva (Hayward, 1942) (not Corticea mendica (Mabille, 1898)), and Choranthus orientis (Skinner, 1920) (not Choranthus antiqua (Herrich-Schäffer, 1863), previously in Pyrrhocalles Mabille, 1904). Borbo impar bipunctata (Elwes and J. Edwards, 1897) is a valid subspecies, not a synonym of Borbo impar tetragraphus (Mabille, 1891), here placed in synonymy with Lotongus calathus (Hewitson, 1876), new synonym. We confirm the species status of Telegonus cassius (Evans, 1952) and Lerema (Morys) valda Evans, 1955. Euphyes chamuli Freeman, 1969 is placed as a subspecies of Euphyes kiowah (Reakirt, 1866), new status. The following 41 taxa are junior subjective synonyms, either newly proposed or transferred from synonymy with other species or subspecies: Telegonus mutius Plötz, 1882 of Euriphellus phraxanor (Hewitson, 1876), Telegonus erythras Mabille, 1888 of Dyscophellus damias (Plötz, 1882), Aethilla jaira Butler, 1870 of Telegonus cretellus (Herrich-Schäffer, 1869), Paches era Evans, 1953 of Santa palica (Mabille, 1888), Antigonus alburnea Plötz, 1884 of Tolius tolimus robigus (Plötz, 1884) (not of Echelatus sempiternus simplicior (Möschler, 1877)), Echelatus depenicillus Strand, 1921 of E. sempiternus simplicior (not of T. tolimus robigus), Antigonus aura Plötz, 1884 of Theagenes dichrous (Mabille, 1878) (not of Helias phalaenoides palpalis (Latreille, [1824])), Achlyodes impressus Mabille, 1889 of Camptopleura orsus (Mabille, 1889), Augiades tania Schaus, 1902 of Metron voranus (Mabille, 1891), Pamphila verdanta Weeks, 1906 of Metron fasciata (Möschler, 1877), Niconiades viridis vista Evans, 1955 of Niconiades derisor (Mabille, 1891), Pamphila binaria Mabille, 1891 of Conga chydaea (A. Butler, 1877) (not of Cynea cynea (Hewitson, 1876)), Psoralis concolor Nicolay, 1980 of Ralis immaculatus (Hayward, 1940), Hesperia dido Plötz, 1882 of Cynea (Quinta) cannae (Herrich-Schäffer, 1869) (not of Lerema lochius (Plötz, 1882)), Proteides osembo Möschler, 1883 of Cynea (Cynea) diluta (Herrich-Schäffer, 1869) (not of Cynea (Quinta) cannae (Herrich-Schäffer, 1869)), Cobalopsis brema E. Bell, 1959 of Eutus rastaca (Schaus, 1902), Psoralis panamensis Anderson and Nakamura, 2019 of Rhomba gertschi (Bell, 1937), Cobalus asella Herrich-Schäffer, 1869 of Amblyscirtes alternata (Grote and Robinson, 1867) (not of Amblyscirtes vialis (W. H. Edwards, 1862)), Papias trimacula Nicolay, 1973 of Nastra subsordida (Mabille, 1891), Pamphila bipunctata Mabille, 1889 and Sarega staurus Mabille, 1904 of Lerema pattenii Scudder, 1872 (not of Cymaenes lumina (Herrich-Schäffer, 1869), previously in Lerema Scudder, 1872), Hesperia aethra Plötz, 1886 of Lerema lineosa (Herrich-Schäffer, 1865) (not of Lerema (Morys) compta Butler, 1877), Megistias miaba Schaus, 1902 of Cobalopsis valerius (Möschler, 1879), Phanis sylvia Kaye, 1914 of Lerema etelka (Schaus, 1902) (not of Lerema (Geia) geisa (Möschler, 1879), previously in Morys Godman, 1900), Carystus odilia Burmeister, 1878, Pamphila trebius Mabille, 1891 and Megistias corescene Schaus, 1902 of Cymaenes lumina (Herrich-Schäffer, 1869), Hesperia phocylides Plötz, 1882 of Cymaenes edata (Plötz, 1882) (not of Lerema accius (J. E. Smith, 1797)), Pamphila xenos Mabille, 1898 of Vehilius inca (Scudder, 1872), Mnasilus guianae Lindsey, 1925 of Papias amyrna (Mabille, 1891), Pamphila nubila Mabille, 1891 of Papias integra (Mabille, 1891) (not of Cynea corisana (Plötz, 1882)), Enosis matheri H. Freeman, 1969 of Metiscus atheas Godman, 1900 (previously in Enosis Mabille, 1889), Hesperia infuscata Plötz, 1882 of Mnaseas derasa derasa (Herrich-Schäffer, 1870) (previously Arotis Mabille, 1904), (not of Papias subcostulata (Herrich-Schäffer, 1870)), Pamphila astur Mabille, 1891 of Metiscus angularis (Möschler, 1877) (not of Cymaenes tripunctus theogenis (Capronnier, 1874)), Anthoptus macalpinei H. Freeman, 1969 of Anthoptus inculta (Dyar, 1918), Methionopsis typhon Godman, 1901 of Methionopsis ina (Plötz, 1882), Methionopsis dolor Evans, 1955 of Thargella volasus (Godman, 1901), Hesperia cinica Plötz, 1882 of Dubiella dubius (Stoll, 1781), Cobalus disjuncta Herrich-Schäffer, 1869 of Dubiella dubius (Stoll, 1781) (not of Vettius lafrenaye (Latreille, [1824])), and Saliana vixen Evans, 1955 of Neoxeniades parna (Evans, 1955). The following are new and revised genus-species combinations: Euriphellus cebrenus (Cramer, 1777) (not Salatis Evans, 1952), Gorgopas extensa (Mabille, 1891) (not Polyctor Evans, 1953), Clytius shola (Evans, 1953) (not Staphylus Godman and Salvin, 1896), Perus narycus (Mabille, 1889) (not Ouleus Lindsey, 1925), Perus parvus (Steinhauser and Austin, 1993) (not Staphylus Godman and Salvin, 1896), Pholisora litus (Dyar, 1912) (not Bolla Mabille, 1903), Carrhenes decens (A. Butler, 1874) (not Antigonus Hübner, [1819]), Santa palica (Mabille, 1888) (not Chiothion Grishin, 2019), Bralus nadia (Nicolay, 1980) (not Anisochoria Mabille, 1876), Acerbas sarala (de Nicéville, 1889) (not Lotongus Distant, 1886), Caenides sophia (Evans, 1937) (not Hypoleucis Mabille, 1891), Hypoleucis dacena (Hewitson, 1876) (not Caenides Holland, 1896), Dotta tura (Evans, 1951) (not Astictopterus C. Felder and R. Felder, 1860), Nervia wallengrenii (Trimen, 1883) (not Kedestes Watson, 1893), Testia mammaea (Hewitson, 1876) (not Decinea Evans, 1955), Oxynthes trinka (Evans, 1955) (not Orthos Evans, 1955), Metrocles argentea (Weeks, 1901) (not Paratrytone Godman, 1900), Metrocles scitula (Hayward, 1951) (not Mucia Godman, 1900), Metrocles schrottkyi (Giacomelli, 1911) (not Metron Godman, 1900), Niconiades derisor (Mabille, 1891) (not Decinea Evans, 1955), Paratrytone samenta (Dyar, 1914) (not Ochlodes Scudder, 1872), Oligoria (Cobaloides) locutia (Hewitson, 1876) (not Quinta Evans, 1955), Psoralis (Saniba) laska (Evans, 1955) (not Vidius Evans, 1955), Psoralis (Saniba) arva (Evans, 1955) and Psoralis (Saniba) umbrata (Erschoff, 1876) (not Vettius Godman, 1901), Psoralis (Saniba) calcarea (Schaus, 1902) and Psoralis (Saniba) visendus (E. Bell, 1942) (not Molo Godman, 1900), Alychna gota (Evans, 1955) (not Psoralis Mabille, 1904), Adlerodea asema (Mabille, 1891) and Adlerodea subpunctata (Hayward, 1940) (not Eutychide Godman, 1900), Ralis immaculatus (Hayward, 1940) (not Mucia Godman, 1900), Rhinthon braesia (Hewitson, 1867) and Rhinthon bajula (Schaus, 1902) (not Neoxeniades Hayward, 1938), Cymaenes lochius Plötz, 1882 (not Lerema Scudder, 1872), Paracarystus ranka (Evans, 1955) (not Thoon Godman, 1900), Tricrista aethus (Hayward, 1951), Tricrista canta (Evans, 1955), Tricrista slopa (Evans, 1955), Tricrista circellata (Plötz, 1882), and Tricrista taxes (Godman, 1900) (not Thoon Godman, 1900), Gallio madius (E. Bell, 1941) and Gallio seriatus (Mabille, 1891) (not Vehilius Godman, 1900), Gallio garima (Schaus, 1902) (not Tigasis Godman, 1900), Tigasis corope (Herrich-Schäffer, 1869) (not Cynea Evans, 1955), Tigasis perloides (Plötz, 1882) (not Cymaenes Scudder, 1872), Amblyscirtes (Flor) florus (Godman, 1900) (not Repens Evans, 1955), Vidius fraus (Godman, 1900) (not Cymaenes Scudder, 1872), Nastra celeus (Mabille, 1891) (not Vehilius Godman, 1900), Nastra nappa (Evans, 1955) (not Vidius Evans, 1955), Vehilius warreni (Weeks, 1901) and Vehilius limae (Lindsey, 1925) (not Cymaenes Scudder, 1872), Cymaenes lumina (Herrich-Schäffer, 1869) (not Lerema Scudder, 1872), Cobalopsis valerius (Möschler, 1879) (not Cobalopsis Godman, 1900), Cobalopsis dictys (Godman, 1900) (not Papias Godman, 1900), Lerema (Morys) venias (Bell, 1942) (not Cobalopsis Godman, 1900), Papias latonia (Schaus, 1913) (not Cobalopsis Godman, 1900), Dion iccius (Evans, 1955) and Dion uza (Hewitson, 1877) (not Enosis Mabille, 1889), Vistigma (Vistigma) opus (Steinhauser, 2008) (not Thoon Godman, 1900), Saturnus fartuga (Schaus, 1902) (not Parphorus Godman, 1900), Phlebodes fuldai (E. Bell, 1930) (not Vettius Godman, 1901), Mnasitheus padus (Evans, 1955) (not Moeris Godman, 1900), Naevolus brunnescens (Hayward, 1939) (not Psoralis Mabille, 1904), Lamponia ploetzii (Capronnier, 1874) (not Vettius Godman, 1901), Mnestheus silvaticus Hayward, 1940 (not Ludens Evans, 1955), Rigga spangla (Evans, 1955) (not Sodalia Evans, 1955), Corticea vicinus (Plötz, 1884) (not Lento Evans, 1955), Mnasalcas thymoetes (Hayward, 1942) (not Mnasicles Godman, 1901), Mnasalcas boyaca (Nicolay, 1973) (not Pamba Evans, 1955), Vertica brasta (Evans, 1955) (not Lychnuchus Hübner, [1831]), Carystina discors Plötz, 1882 (not Cobalus Hübner, [1819]), Zetka irena (Evans, 1955) (not Neoxeniades Hayward, 1938), and Neoxeniades parna (Evans, 1955) (not Niconiades Hübner, [1821]). The following are new or revised species-subspecies combinations: Tagiades neira moti Evans, 1934, Tagiades neira canonicus Fruhstorfer, 1910, Tagiades sheba vella Evans, 1934, Tagiades sheba lola Evans, 1945, Tagiades korela biakana Evans, 1934, Tagiades korela mefora Evans, 1934, Tagiades korela suffusus Rothschild, 1915, Tagiades korela brunta Evans, 1949, Tagiades ravi ravina Fruhstorfer, 1910, Tagiades atticus carnica Evans, 1934, Tagiades atticus nankowra Evans, 1934, Tagiades atticus helferi C. Felder, 1862, Tagiades atticus balana Fruhstorfer, 1910, Tagiades inconspicua mathias Evans, 1934, Tagiades hovia kazana Evans, 1934, Tagiades elegans fuscata de Jong and Treadaway, 2007, Tagiades elegans semperi Fruhstorfer, 1910, Metron hypochlora tomba Evans, 1955, Decinea denta pruda Evans, 1955, and Choranthus orientis eleutherae (Bates, 1934) (previously in Pyrrhocalles Mabille, 1904). In addition to the abovementioned changes, the following new combinations involve newly proposed genus group names: Fulvatis fulvius (Plötz, 1882) and Fulvatis scyrus (E. Bell, 1934) (not Salatis Evans, 1952); Adina adrastor (Mabille and Boullet, 1912) (not Bungalotis Watson, 1893); Nascus (Praxa) prax Evans, 1952, Nascus (Bron) broteas (Cramer, 1780), and Nascus (Bron) solon (Plötz, 1882) (not Pseudonascus Austin, 2008); Chirgus (Turis) veturius (Plötz, 1884); Paches (Tiges) liborius (Plötz, 1884), and Paches (Tiges) mutilatus (Hopffer, 1874) (not Antigonus Hübner, [1819]); Paches (Tiges) exosa (A. Butler, 1877); Tolius tolimus (Plötz, 1884) and Tolius luctuosus (Godman & Salvin, 1894) (not Echelatus Godman and Salvin, 1894); Ancistroides (Ocrypta) caerulea (Evans, 1928), Ancistroides (Ocrypta) renardi (Oberthür, 1878), Ancistroides (Ocrypta) waigensis (Plötz, 1882), Ancistroides (Ocrypta) aluensis (Swinhoe, 1907), Ancistroides (Ocrypta) flavipes (Janson, 1886), and Ancistroides (Ocrypta) maria (Evans, 1949) (not Notocrypta de Nicéville, 1889); Lennia lena (Evans, 1937), Lennia binoevatus (Mabille, 1891), Lennia maracanda (Hewitson, 1876), and Lennia lota (Evans, 1937) (not Leona Evans, 1937); Trida barberae (Trimen, 1873) and Trida sarahae (Henning and Henning, 1998) (not Kedestes Watson, 1893); Noxys viricuculla (Hayward, 1951) (not Oxynthes Godman, 1900); Xeniades (Tixe) quadrata (Herrich-Schäffer, 1869), Xeniades (Tixe) rinda (Evans, 1955), Xeniades (Tixe) putumayo (Constantino and Salazar, 2013) (not Tisias Godman, 1901); Gracilata quadrinotata (Mabille, 1889) (not Styriodes Schaus, 1913); Hermio hermione (Schaus, 1913) (not Lento Evans, 1955); Cynea (Nycea) hycsos (Mabille, 1891), Cynea (Nycea) corisana (Plötz, 1882), Cynea (Nycea) popla Evans, 1955, Cynea (Nycea) iquita (E. Bell, 1941), Cynea (Nycea) robba Evans, 1955, Cynea (Nycea) melius (Geyer, 1832), and Cynea (Nycea) irma (Möschler, 1879); Eutus rastaca (Schaus, 1902) (not Eutychide Godman, 1900); Eutus yesta (Evans, 1955) (not Thoon Godman, 1900); Eutus mubevensis (E. Bell, 1932) (not Tigasis Godman, 1900); Gufa gulala (Schaus, 1902) (not Mucia Godman, 1900); Gufa fusca (Hayward, 1940) (not Tigasis Godman, 1900); Godmia chlorocephala (Godman, 1900) (not Onophas Godman, 1900); Rhomba gertschi (E. Bell, 1937) (not Justinia Evans, 1955); Mnasicles (Nausia) nausiphanes (Schaus, 1913) (not Tigasis Godman, 1900); Amblyscirtes (Flor) florus (Godman, 1900) (not Repens Evans, 1955); Rectava ignarus (E. Bell, 1932) (not Papias Godman, 1900); Rectava vorgia (Schaus, 1902) (not Cobalopsis Godman, 1900); Rectava nostra (Evans, 1955) (not not Vidius Evans, 1955); Lerema (Geia) geisa (Möschler, 1879) and Lerema (Geia) lyde (Godman, 1900) (not Morys Godman, 1900); Contrastia distigma (Plötz, 1882) (not Cymaenes Scudder, 1872); Mit (Mit) badius (E. Bell, 1930) (not Styriodes Schaus, 1913); Mit (Mit) gemignanii (Hayward, 1940), (not Mnasitheus Godman, 1900); Mit (Rotundia) schausi (Mielke and Casagrande, 2002), (not Enosis Mabille, 1889); Picova steinbachi (E. Bell, 1930) (not Saturnus Evans, 1955); Lattus arabupuana (E. Bell, 1932) (not Eutocus Godman, 1901); Gubrus lugubris (Lindsey, 1925) (not Vehilius Godman, 1900); Thargella (Pseudopapias) tristissimus (Schaus, 1902) (not Papias Godman, 1900); Koria kora (Hewitson, 1877) (not Justinia Evans, 1955); Justinia (Septia) septa Evans, 1955; Corta lycortas (Godman, 1900) (not Orthos Evans, 1955); Vertica (Brasta) brasta (Evans, 1955) (not Lychnuchus Hübner, [1831]); Calvetta calvina (Hewitson, 1866) (not Cobalus Hübner, [1819]); Neoxeniades (Bina) gabina (Godman, 1900) (not Orthos Evans, 1955); Oz ozias (Hewitson, 1878) and Oz sebastiani Salazar and Constantino, 2013 (not Lychnuchoides Godman, 1901); and Carystoides (Balma) balza Evans, 1955 and Carystoides (Balma) maroma (Möschler, 1877). Finally, unless stated otherwise, all subgenera, species, subspecies and synonyms of mentioned genera and species are transferred together with their parent taxa, and taxa not mentioned in this work remain as previously classified.

Genomics Reveals the Origins of Historical Specimens

Centuries of zoological studies have amassed billions of specimens in collections worldwide. Genomics of these specimens promises to reinvigorate biodiversity research. However, because DNA degrades with age in historical specimens, it is a challenge to obtain genomic data for them and analyze degraded genomes. We developed experimental and computational protocols to overcome these challenges and applied our methods to resolve a series of long-standing controversies involving a group of butterflies. We deduced the geographical origins of several historical specimens of uncertain provenance that are at the heart of these debates. Here, genomics tackles one of the greatest problems in zoology: countless old specimens that serve as irreplaceable embodiments of species concepts cannot be confidently assigned to extant species or population due to the lack of diagnostic morphological features and clear documentation of the collection locality. The ability to determine where they were collected will resolve many on-going disputes. More broadly, we show the utility of applying genomics to historical museum specimens to delineate the boundaries of species and populations, and to hypothesize about genotypic determinants of phenotypic traits.

Disentangling Population History and Character Evolution among Hybridizing Lineages

Understanding the origin and maintenance of adaptive phenotypic novelty is a central goal of evolutionary biology. However, both hybridization and incomplete lineage sorting can lead to genealogical discordance between the regions of the genome underlying adaptive traits and the remainder of the genome, decoupling inferences about character evolution from population history. Here, to disentangle these effects, we investigated the evolutionary origins and maintenance of Batesian mimicry between North American admiral butterflies (Limenitis arthemis) and their chemically defended model (Battus philenor) using a combination of de novo genome sequencing, whole-genome resequencing, and statistical introgression mapping. Our results suggest that balancing selection, arising from geographic variation in the presence or absence of the unpalatable model, has maintained two deeply divergent color patterning haplotypes that have been repeatedly sieved among distinct mimetic and nonmimetic lineages of Limenitis via introgressive hybridization.

Rational design of Lepidoptera-specific insecticidal inhibitors targeting farnesyl diphosphate synthase, a key enzyme of the juvenile hormone biosynthetic pathway

Reducing the use of broad-spectrum insecticides is one of the many challenges currently faced by insect pest management practitioners. For this reason, efforts are being made to develop environmentally benign pest-control products through bio-rational approaches that aim at disrupting physiological processes unique to specific groups of pests. Perturbation of hormonal regulation of insect development and reproduction is one such strategy. It has long been hypothesized that some enzymes in the juvenile hormone biosynthetic pathway of moths, butterflies and caterpillars (order Lepidoptera) display unique structural features that could be targeted for the development of Lepidoptera-specific insecticides, a promising avenue given the numerous agricultural and forest pests belonging to this order. Farnesyl diphosphate synthase, FPPS, is one such enzyme, with recent work suggesting that it has structural characteristics that may enable its selective inhibition. This review synthesizes current knowledge on FPPS and summarizes recent advances in its use as a target for insecticide development.

Genome-wide macroevolutionary signatures of key innovations in butterflies colonizing new host plants

The mega-diversity of herbivorous insects is attributed to their co-evolutionary associations with plants. Despite abundant studies on insect-plant interactions, we do not know whether host-plant shifts have impacted both genomic adaptation and species diversification over geological times. We show that the antagonistic insect-plant interaction between swallowtail butterflies and the highly toxic birthworts began 55 million years ago in Beringia, followed by several major ancient host-plant shifts. This evolutionary framework provides a valuable opportunity for repeated tests of genomic signatures of macroevolutionary changes and estimation of diversification rates across their phylogeny. We find that host-plant shifts in butterflies are associated with both genome-wide adaptive molecular evolution (more genes under positive selection) and repeated bursts of speciation rates, contributing to an increase in global diversification through time. Our study links ecological changes, genome-wide adaptations and macroevolutionary consequences, lending support to the importance of ecological interactions as evolutionary drivers over long time periods.

Chromosome-level genome of the peach fruit moth Carposina sasakii (Lepidoptera: Carposinidae) provides a resource for evolutionary studies on moths

The peach fruit moth (PFM), Carposina sasakii Matsumura, is a major phytophagous orchard pest widely distributed across Northeast Asia. Here, we report the chromosome-level genome for the PFM, representing the first genome for the family Carposinidae, from the lepidopteran superfamily Copromorphoidea. The genome was assembled into 404.83 Mb sequences using PacBio long-read and Illumina short-read sequences, including 275 contigs, with a contig N50 length of 2.62 Mb. All contigs were assembled into 31 linkage groups assisted by the Hi-C technique, including 30 autosomes and a Z chromosome. BUSCO analysis showed that 98.3% of genes were complete and 0.4% of genes were fragmented, while 1.3% of genes were missing in the assembled genome. In total, 21,697 protein-coding genes were predicted, of which 84.80% were functionally annotated. Because of the importance of diapause triggered by photoperiod in PFM, five circadian genes in the PFM as well as in the other related species were annotated, and potential genes related to diapause and photoperiodic reaction were also identified from transcriptome sequencing. In addition, manual annotation of detoxification gene families was undertaken and showed a higher number of glutathione S-transferase (GST) gene in PFM than in most other lepidopterans, in contrast to a lower number of uridine diphosphate (UDP)-glycosyltransferase (UGT) gene, carboxyl/cholinesterases (CCE) gene and cytochrome P450 monooxygenase (P450) gene, suggesting different detoxication pathways in this moth. The high-quality genome provides a resource for comparative evolutionary studies of this moth and its relatives within the context of radiations across Lepidoptera.

Genomic evidence suggests further changes of butterfly names

Further genomic sequencing of butterflies by our research group expanding the coverage of species and specimens from different localities, coupled with genome-scale phylogenetic analysis and complemented by phenotypic considerations, suggests a number of changes to the names of butterflies, mostly those recorded from the United States and Canada. Here, we present evidence to support these changes. The changes are intended to make butterfly classification more internally consistent at the genus, subgenus and species levels. I.e., considering all available evidence, we attempt to assign similar taxonomic ranks to the clades of comparable genetic differentiation, which on average is correlated with the age of phylogenetic groups estimated from trees. For species, we use criteria devised by genomic analysis of the genetic differentiation across suture zones and comparison of sympatric populations of closely related species. As a result, we resurrect 4 genera and 1 subgenus from subgeneric status or synonymy, change the rank of 8 currently used genera to subgenus, synonymize 7 genus-group names, summarize evidence to support 19 taxa as species instead of subspecies and 1 taxon as subspecies instead of species, along with a number of additional changes. One new genus and one new subspecies are described. Namely, the following taxa are treated as genera Tharsalea Scudder, 1876, Helleia Verity, 1943, Apangea Zhdanko, 1995, and Boldenaria Zhdanko, 1995. Tetracharis Grote, 1898 is a valid subgenus (not a synonym of Anthocharis Boisduval, Rambur, [Duménil] & Graslin, [1833]) that consists of Anthocharis cethura C. Felder & R. Felder, 1865 (Müller, 1764), Anthocharis midea (Hübner, [1809]), and Anthocharis limonea (A. Butler, 1871). The following are subgenera: Speyeria Scudder, 1872 of Argynnis Fabricius, 1807; Aglais Dalman, 1816 and Polygonia Hübner, [1819] of Nymphalis Kluk, 1780; Palaeonympha Butler, 1871 of Megisto Hübner, [1819]; Hyponephele Muschamp, 1915 of Cercyonis Scudder, 1875; Pyronia Hübner, [1819] and Aphantopus Wallengren, 1853 of Maniola Schrank, 1801 and Pseudonymphidia Callaghan, 1985 of Pachythone. Lafron Grishin, gen. n. (type species Papilio orus Stoll, [1780], parent subfamily Lycaeninae [Leach], [1815]) is described. Dipsas japonica Murray, 1875 is fixed as the type species of Neozephyrus Sibatani & Ito, 1942. The following taxa are junior subjective synonyms: Falcapica Klots, 1930 of Tetracharis Grote, 1898; Habrodais Scudder, 1876, Favonius Sibatani & Ito, 1942, Neozephyrus Sibatani & Ito, 1942, Quercusia Verity, 1943, Chrysozephyrus Shirôzu & Yamamoto, 1956, and Sibataniozephyrus Inomata, 1986 of Hypaurotis Scudder, 1876; Plesioarida Trujano & García, 2018 of Roeberella Strand, 1932; Papilio temenes Godart, 1819 (lectotype designated herein) of Heraclides aristodemus (Esper, 1794), Speyeria hydaspe conquista dos Passos & Grey, 1945 of Argynnis hesperis tetonia (dos Passos & Grey, 1945), and Erycides imbreus Plötz, 1879 of Phocides polybius polybius (Fabricius, 1793). The following are revised genus-species combinations: Pachythone lencates (Hewitson, 1875) Pachythone flocculus (Brévignon & Gallard, 1993), Pachythone floccus (Brévignon, 2013), Pachythone heberti (P. Jauffret & J. Jauffret, 2007), Pachythone marajoara (P. Jauffret & J. Jauffret, 2007) and Cissia cleophes (Godman & Salvin, 1889). The following species are transferred between subgenera: Anthocharis lanceolata Lucas, 1852 belongs to Anthocharis Boisduval, Rambur, [Duménil] & Graslin, [1833] instead of Paramidea Kuznetsov, 1929 and Danaus eresimus (Cramer, 1777) belongs to Danaus Kluk, 1780, and not to Anosia Hübner, 1816. The following taxa are distinct species rather than subspecies (of species shown in parenthesis): Heraclides ponceana (Schaus, 1911) (not Heraclides aristodemus (Esper, 1794)), Colias elis Strecker, 1885 (not Colias meadii W. H. Edwards, 1871), Argynnis irene Boisduval, 1869 and Argynnis nausicaa W. H. Edwards, 1874 (not Argynnis hesperis W. H. Edwards, 1864), Coenonympha california Westwood, [1851] (not Coenonympha tullia (Müller, 1764)), Dione incarnata N. Riley, 1926 (not Dione vanillae (Linnaeus, 1758)), Chlosyne coronado (M. Smith & Brock, 1988) (not Chlosyne fulvia (W. H. Edwards, 1879)), Chlosyne chinatiensis (Tinkham, 1944) (not Chlosyne theona (Ménétriés, 1855)), Phocides lilea (Reakirt, [1867]) (not Phocides polybius (Fabricius, 1793)), Cecropterus nevada (Scudder, 1872) and Cecropterus dobra (Evans, 1952) (not Cecropterus mexicana (Herrich-Schäffer, 1869)), Telegonus anausis Godman & Salvin, 1896, (not Telegonus anaphus (Cramer, 1777)), Epargyreus huachuca Dixon, 1955 (not Epargyreus clarus (Cramer, 1775)), Nisoniades bromias (Godman & Salvin, 1894) (not Nisoniades rubescens (Möschler, 1877)), Pholisora crestar J. Scott & Davenport, 2017 (not Pholisora catullus (Fabricius, 1793)), Carterocephalus mandan (W. H. Edwards, 1863) and Carterocephalus skada (W. H. Edwards, 1870) (not Carterocephalus palaemon (Pallas, 1771)), Amblyscirtes arizonae H. Freeman, 1993 (not Amblyscirtes elissa Godman, 1900), and Megathymus violae D. Stallings & Turner, 1956 (not Megathymus ursus Poling, 1902). Resulting from these changes, the following are revised species-subspecies combinations: Heraclides ponceana bjorndalae (Clench, 1979), Heraclides ponceana majasi L. Miller, 1987, Argynnis irene dodgei Gunder, 1931, Argynnis irene cottlei J. A. Comstock, 1925, Argynnis irene hanseni (J. Emmel, T. Emmel & Mattoon, 1998), Argynnis nausicaa elko (Austin, 1984), Argynnis nausicaa greyi (Moeck, 1950), Argynnis nausicaa viola (dos Passos & Grey, 1945), Argynnis nausicaa tetonia (dos Passos & Grey, 1945), Argynnis nausicaa chitone W. H. Edwards, 1879, Argynnis nausicaa schellbachi (Garth, 1949), Argynnis nausicaa electa W. H. Edwards, 1878, Argynnis nausicaa dorothea (Moeck, 1947), and Argynnis nausicaa capitanensis (R. Holland, 1988), Argynnis zerene atossa W. H. Edwards, 1890, Dione incarnata nigrior (Michener, 1942), Chlosyne coronado pariaensis (M. Smith & Brock, 1988), Cecropterus nevada aemilea (Skinner, 1893), Cecropterus nevada blanca (J. Scott, 1981), Telegonus anausis annetta (Evans, 1952), Telegonus anausis anoma (Evans, 1952), Telegonus anausis aniza (Evans, 1952), Epargyreus huachuca profugus Austin, 1998, Carterocephalus mandan mesapano (Scudder, 1868) and Carterocephalus skada magnus Mattoon & Tilden, 1998. American Coenonympha subspecies placed under C. tullia other than Coenonympha tullia kodiak W. H. Edwards, 1869, Coenonympha tullia mixturata Alpheraky, 1897 and Coenonympha tullia yukonensis W. Holland, 1900 belong to C. california. Heraclides ponceana latefasciatus Grishin, ssp. n. is described from Cuba. Argynnis coronis carolae dos Passos & Grey, 1942 is considered a subspecies-level taxon. Unless stated otherwise, all subgenera, species, subspecies and synonyms of mentioned genera and species are transferred together with their parent taxa, and others remain as previously classified.

Speciation in North American Junonia from a genomic perspective

Delineating species boundaries in phylogenetic groups undergoing recent radiation is a daunting challenge akin to discretizing continuity. Here, we propose a general approach exemplified by American butterflies from the genus Junonia Hübner notorious for the variety of similar phenotypes, ease of hybridization, and the lack of consensus about their classification. We obtain whole-genome shotgun sequences of about 200 specimens. We reason that discreteness emerges from continuity by means of a small number of key players, and search for the proteins that diverged markedly between sympatric populations of different species, while keeping low polymorphism within these species. Being 0.25% of the total number, these three dozen 'speciation' proteins indeed partition pairs of Junonia populations into two clusters with a prominent break in between, while all proteins taken together fail to reveal this discontinuity. Populations with larger divergence from each other, comparable to that between two sympatric species, form the first cluster and correspond to different species. The other cluster is characterized by smaller divergence, similar to that between allopatric populations of the same species and comprise conspecific pairs. Using this method, we conclude that J. genoveva (Cramer), J. litoralis Brévignon, J. evarete (Cramer), and J. divaricata C. & R. Felder are restricted to South America. We find that six species of Junonia are present in the United States, one of which is new: Junonia stemosa Grishin, sp.n. (i), found in south Texas and phenotypically closest to J. nigrosuffusa W. Barnes & McDunnough (ii) in its dark appearance. In the pale nudum of the antennal club, these two species resemble J. zonalis C. & R. Felder (iii) from Florida and the Caribbean Islands. The pair of sister species, J. grisea Austin & J. Emmel (iv) and J. coenia Hübner (v), represent the classic west/east U.S.A. split. The mangrove feeder (as caterpillar), dark nudum J. neildi Brévignon (vi) enters south Texas as a new subspecies Junonia neildi varia Grishin ssp.n. characterized by more extensive hybridization with and introgression from J. coenia, and, as a consequence, more variable wing patterns compared with the nominal J. n. neildi in Florida. Furthermore, a new mangrove-feeding species from the Pacific Coast of Mexico is described as Junonia pacoma Grishin sp.n. Finally, genomic analysis suggests that J. nigrosuffusa may be a hybrid species formed by the ancestors of J. grisea and J. stemosa sp.n.

Assessing ecological and physiological costs of melanism in North American Papilio glaucus females: two decades of dark morph frequency declines

Polymorphisms for melanic form of insects may provide various selective advantages. However, melanic alleles may have significant/subtle pleiotrophic "costs." Several potential pleiotrophic effects of the W (=Y)-linked melanism gene in Papilio glaucus L. (Lepidoptera) showed no costs for melanic versus yellow in adult size, oviposition preferences, fecundity, egg viability, larval survival/growth rates, cold stress tolerance, or postdiapause emergence times. Sexual selection (males choosing yellow rather than mimetic dark females) had been suggested to provide a balanced polymorphism in P. glaucus, but spermatophore counts in wild females and direct field tethering studies of size-matched pairs of virgin females (dark and yellow), show that male preferences are random or frequency-dependent from Florida to Michigan, providing no yellow counter-advantages. Recent frequency declines of dark (melanic/mimetic) females in P. glaucus populations are shown in several major populations from Florida (27.3°N latitude) to Ohio (38.5° N). Summer temperatures have increased significantly at all these locations during this time (1999-2018), but whether dark morphs may be more vulnerable (in any stage) to such climate warming remains to be determined. Additional potential reasons for the frequency declines in mimetic females are discussed: (i) genetic introgression of Z-linked melanism suppressor genes from P. canadensis (R & J) and the hybrid species, P. appalachiensis (Pavulaan & Wright), (ii) differential developmental incompatibilities, or Haldane effects, known to occur in hybrids, (iii) selection against intermediately melanic ("dusty") females (with the W-linked melanic gene, b+) which higher temperatures can cause.

Genomes reveal drastic and recurrent phenotypic divergence in firetip skipper butterflies (Hesperiidae: Pyrrhopyginae)

Biologists marvel at the powers of adaptive convergence, when distantly related animals look alike. While mimetic wing patterns of butterflies have fooled predators for millennia, entomologists inferred that mimics were distant relatives despite similar appearance. However, the obverse question has not been frequently asked. Who are the close relatives of mimetic butterflies and what are their features? As opposed to close convergence, divergence from a non-mimetic relative would also be extreme. When closely related animals look unalike, it is challenging to pair them. Genomic analysis promises to elucidate evolutionary relationships and shed light on molecular mechanisms of divergence. We chose the firetip skipper butterfly as a model due to its phenotypic diversity and abundance of mimicry. We sequenced and analysed whole genomes of nearly 120 representative species. Genomes partitioned this subfamily Pyrrhopyginae into five tribes (1 new), 23 genera and, additionally, 22 subgenera (10 new). The largest tribe Pyrrhopygini is divided into four subtribes (three new). Surprisingly, we found five cases where a uniquely patterned butterfly was formerly placed in a genus of its own and separately from its close relatives. In several cases, extreme and rapid phenotypic divergence involved not only wing patterns but also the structure of the male genitalia. The visually striking wing pattern difference between close relatives frequently involves disappearance or suffusion of spots and colour exchange between orange and blue. These differences (in particular, a transition between unspotted black and striped wings) happen recurrently on a short evolutionary time scale, and are therefore probably achieved by a small number of mutations.

Recent hybrids recapitulate ancient hybrid outcomes

Genomic outcomes of hybridization depend on selection and recombination in hybrids. Whether these processes have similar effects on hybrid genome composition in contemporary hybrid zones versus ancient hybrid lineages is unknown. Here we show that patterns of introgression in a contemporary hybrid zone in Lycaeides butterflies predict patterns of ancestry in geographically adjacent, older hybrid populations. We find a particularly striking lack of ancestry from one of the hybridizing taxa, Lycaeides melissa, on the Z chromosome in both the old and contemporary hybrids. The same pattern of reduced L. melissa ancestry on the Z chromosome is seen in two other ancient hybrid lineages. More generally, we find that patterns of ancestry in old or ancient hybrids are remarkably predictable from contemporary hybrids, which suggests selection and recombination affect hybrid genomes in a similar way across disparate time scales and during distinct stages of speciation and species breakdown.

Butterfly Mimicry Polymorphisms Highlight Phylogenetic Limits of Gene Reuse in the Evolution of Diverse Adaptations

Some genes have repeatedly been found to control diverse adaptations in a wide variety of organisms. Such gene reuse reveals not only the diversity of phenotypes these unique genes control but also the composition of developmental gene networks and the genetic routes available to and taken by organisms during adaptation. However, the causes of gene reuse remain unclear. A small number of large-effect Mendelian loci control a huge diversity of mimetic butterfly wing color patterns, but reasons for their reuse are difficult to identify because the genetic basis of mimicry has primarily been studied in two systems with correlated factors: female-limited Batesian mimicry in Papilio swallowtails (Papilionidae) and non-sex-limited Müllerian mimicry in Heliconius longwings (Nymphalidae). Here, we break the correlation between phylogenetic relationship and sex-limited mimicry by identifying loci controlling female-limited mimicry polymorphism Hypolimnas misippus (Nymphalidae) and non-sex-limited mimicry polymorphism in Papilio clytia (Papilionidae). The Papilio clytia polymorphism is controlled by the genome region containing the gene cortex, the classic P supergene in Heliconius numata, and loci controlling color pattern variation across Lepidoptera. In contrast, female-limited mimicry polymorphism in Hypolimnas misippus is associated with a locus not previously implicated in color patterning. Thus, although many species repeatedly converged on cortex and its neighboring genes over 120 My of evolution of diverse color patterns, female-limited mimicry polymorphisms each evolved using a different gene. Our results support conclusions that gene reuse occurs mainly within ∼10 My and highlight the puzzling diversity of genes controlling seemingly complex female-limited mimicry polymorphisms.

Insect genomes: progress and challenges

In the wake of constant improvements in sequencing technologies, numerous insect genomes have been sequenced. Currently, 1219 insect genome-sequencing projects have been registered with the National Center for Biotechnology Information, including 401 that have genome assemblies and 155 with an official gene set of annotated protein-coding genes. Comparative genomics analysis showed that the expansion or contraction of gene families was associated with well-studied physiological traits such as immune system, metabolic detoxification, parasitism and polyphagy in insects. Here, we summarize the progress of insect genome sequencing, with an emphasis on how this impacts research on pest control. We begin with a brief introduction to the basic concepts of genome assembly, annotation and metrics for evaluating the quality of draft assemblies. We then provide an overview of genome information for numerous insect species, highlighting examples from prominent model organisms, agricultural pests and disease vectors. We also introduce the major insect genome databases. The increasing availability of insect genomic resources is beneficial for developing alternative pest control methods. However, many opportunities remain for developing data-mining tools that make maximal use of the available insect genome resources. Although rapid progress has been achieved, many challenges remain in the field of insect genomics.

Expansion of LINEs and species-specific DNA repeats drives genome expansion in Asian Gypsy Moths

Two subspecies of Asian gypsy moth (AGM), Lymantria dispar asiatica and L. dispar japonica, pose a serious alien invasive threat to North American forests. Despite decades of research on the ecology and biology of this pest, limited AGM-specific genomic resources are currently available. Here, we report on the genome sequences and functional content of these AGM subspecies. The genomes of L.d. asiatica and L.d. japonica are the largest lepidopteran genomes sequenced to date, totaling 921 and 999 megabases, respectively. Large genome size in these subspecies is driven by the accumulation of specific classes of repeats. Genome-wide metabolic pathway reconstructions suggest strong genomic signatures of energy-related pathways in both subspecies, dominated by metabolic functions related to thermogenesis. The genome sequences reported here will provide tools for probing the molecular mechanisms underlying phenotypic traits that are thought to enhance AGM invasiveness.

Fifty new genera of Hesperiidae (Lepidoptera)

Genomic sequencing and analysis of worldwide skipper butterfly (Lepidoptera: Hesperiidae) fauna points to imperfections in their current classification. Some tribes, subtribes and genera as they are circumscribed today are not monophyletic. Rationalizing genomic results from the perspective of phenotypic characters suggests two new tribes, two new subtribes and 50 new genera that are named here: Ceratrichiini Grishin, trib. n., Gretnini Grishin, trib. n., Falgina Grishin, subtr. n., Apaustina Grishin, subtr. n., Flattoides Grishin, gen. n., Aurivittia Grishin, gen. n., Viuria Grishin, gen. n., Clytius Grishin, gen. n., Incisus Grishin, gen. n., Perus Grishin, gen. n., Livida Grishin, gen. n., Festivia Grishin, gen. n., Hoodus Grishin, gen. n., Anaxas Grishin, gen. n., Chiothion Grishin, gen. n., Crenda Grishin, gen. n., Santa Grishin, gen. n., Canesia Grishin, gen. n., Bralus Grishin, gen. n., Ladda Grishin, gen. n., Willema Grishin, gen. n., Argemma Grishin, gen. n., Nervia Grishin, gen. n., Dotta Grishin, gen. n., Lissia Grishin, gen. n., Xanthonymus Grishin, gen. n., Cerba Grishin, gen. n., Avestia Grishin, gen. n., Zetka Grishin, gen. n., Turmosa Grishin, gen. n., Mielkeus Grishin, gen. n., Coolus Grishin, gen. n., Daron Grishin, gen. n., Barrolla Grishin, gen. n., Brownus Grishin, gen. n., Tava Grishin, gen. n., Rigga Grishin, gen. n., Haza Grishin, gen. n., Dubia Grishin, gen. n., Pares Grishin, gen. n., Chitta Grishin, gen. n., Artonia Grishin, gen. n., Lurida Grishin, gen. n., Corra Grishin, gen. n., Fidius Grishin, gen. n., Veadda Grishin, gen. n., Tricrista Grishin, gen. n., Viridina Grishin, gen. n., Alychna Grishin, gen. n., Ralis Grishin, gen. n., Testia Grishin, gen. n., Buzella Grishin, gen. n., Vernia Grishin, gen. n., and Lon Grishin, gen. n. In addition, the following taxonomic changes are suggested. Prada Evans is transferred from Hesperiinae to Trapezitinae. Echelatus Godman and Salvin, Systaspes Weeks, and Oenides Mabille are removed from synonymy and are treated as valid genera. The following genera are new junior subjective synonyms: Tosta Evans of Eantis Boisduval; Turmada Evans of Neoxeniades Hayward, Arita Evans of Tigasis Godman, and Alera Mabille of Perichares Scudder. Eantis pallida (R. Felder) (not Achlyodes Hübner), Gindanes kelso (Evans) (not Onenses Godman and Salvin), Isoteinon abjecta (Snellen) (not Astictopterus C. and R. Felder), Neoxeniades ethoda (Hewitson) (not Xeniades Godman), Moeris anna (Mabille) (not Vidius Evans), and Molo pelta Evans (not Lychnuchus Hübner) are new genus-species combinations. The following are species-level taxa: Livida assecla (Mabille) (not a subspecies of Livida grandis (Mabille), formerly Pythonides Hübner) and Alychna zenus (E. Bell) (not a junior subjective synonym of Alychna exclamationis (Mabille), formerly Psoralis Mabille); and Barrolla molla E. Bell (formerly Vacerra Godman) is a junior subjective synonym of Barrolla barroni Evans (formerly Paratrytone Godman). All these changes to taxonomic status of names are propagated to all names currently treated as subspecies (for species), subgenera (for genera) and synonyms of these taxa. Finally, taxa not mentioned in this work are considered to remain at the ranks and in taxonomic groups they have been previously assigned to.

Chromosomal-level reference genome of Chinese peacock butterfly (Papilio bianor) based on third-generation DNA sequencing and Hi-C analysis

BACKGROUND

Papilio bianor Cramer, 1777 (commonly known as the Chinese peacock butterfly) (Insecta, Lepidoptera, Papilionidae) is a widely distributed swallowtail butterfly with a wide number of geographic populations ranging from the southeast of Russia to China, Japan, India, Vietnam, Myanmar, and Thailand. Its wing color consists of both pigmentary colored scales (black, reddish) and structural colored scales (iridescent blue or green dust). A high-quality reference genome of P. bianor is an important foundation for investigating iridescent color evolution, phylogeography, and the evolution of swallowtail butterflies.

FINDINGS

We obtained a chromosome-level de novo genome assembly of the highly heterozygous P. bianor using long Pacific Biosciences sequencing reads and high-throughput chromosome conformation capture technology. The final assembly is 421.52 Mb on 30 chromosomes (29 autosomes and 1 Z sex chromosome) with 13.12 Mb scaffold N50. In total, 15,375 protein-coding genes and 233.09 Mb of repetitive sequences were identified. Phylogenetic analyses indicated that P. bianor separated from a common ancestor of swallowtails ∼23.69-36.04 million years ago. Demographic history suggested that the population expansion of this species from the last interglacial period to the last glacial maximum possibly resulted from its decreased natural enemies and its adaptation to climate change during the glacial period.

CONCLUSIONS

We present a high-quality chromosome-level reference genome of P. bianor using long-read single-molecule sequencing and Hi-C-based chromatin interaction maps. Our results lay the foundation for exploring the genetic basis of special biological features of P. bianor and also provide a useful data source for comparative genomics and phylogenomics among butterflies and moths.

Genomic analysis of the tribe Emesidini (Lepidoptera: Riodinidae)

We obtained and phylogenetically analyzed whole genome shotgun sequences of nearly all species from the tribe Emesidini Seraphim, Freitas & Kaminski, 2018 (Riodinidae) and representatives from other Riodinidae tribes. We see that the recently proposed genera Neoapodemia Trujano, 2018 and Plesioarida Trujano & García, 2018 are closely allied with Apodemia C. & R. Felder, [1865] and are better viewed as its subgenera, new status. Overall, Emesis Fabricius, 1807 and Apodemia (even after inclusion of the two subgenera) are so phylogenetically close that several species have been previously swapped between these two genera. New combinations are: Apodemia (Neoapodemia) zela (Butler, 1870), Apodemia (Neoapodemia) ares (Edwards, 1882), and Apodemia (Neoapodemia) arnacis (Stichel, 1928) (not Emesis); and Emesis phyciodoides (Barnes & Benjamin, 1924) (not Apodemia), assigned to each genus by their monophyly in genomic trees with the type species (TS) of the genus. Surprisingly, we find that Emesis emesia Hewitson, 1867 is not grouped with Emesis, but in addition to Apodemia forms a third lineage of similar rank, here named Curvie Grishin, gen. n. (TS: Symmachia emesia Hewitson, 1867). Furthermore, we partition Emesis into 6 subgenera (4 new): Emesis (TS: Hesperia ovidius Fabricius, 1793, a subjective junior synonym of Papilio cereus Linnaeus, 1767), Aphacitis Hübner, [1819] (TS: Papilio dyndima Cramer, [1780], a subjective junior synonym of Papilio lucinda Cramer, [1775]), Poeasia Grishin, subgen. n. (TS: Emesis poeas Godman, [1901]), Mandania Grishin, subgen. n. (TS: Papilio mandana Cramer, [1780]), Brimia Grishin, subgen. n. (TS: Emesis brimo Godman & Salvin, 1889), and Tenedia Grishin, subgen. n. (TS: Emesis tenedia C. & R. Felder, 1861). Next, genomic comparison of primary type specimens suggests new status for Emesis vimena Schaus, 1928 as a subspecies of Emesis brimo Godman & Salvin, 1889, Emesis adelpha Le Cerf, 1958 with E. a. vicaria Le Cerf, 1958 are subspecies of Emesis heteroclita Stichel, 1929, and Emesis tristis Stichel, 1929 is not a synonym of E. brimo vimena but of Emesis lupina Godman & Salvin, 1886. A new status of a species is given to the following taxa: Emesis furor A. Butler & H. Druce, 1872 (not a subspecies of E. mandana (Cramer, 1780)), Emesis melancholica Stichel, 1916 (not a subspecies of E. lupina Godman & Salvin, 1886), Emesis progne (Godman, 1903) (not a subspecies of E. brimo Godman & Salvin, 1889), and Emesis opaca Stichel, 1910 (not a synonym of E. lucinda (Cramer, 1775)). Emesis castigata diringeriGallard 2008 is a subjective junior synonym of E. opaca, new status. Finally, Xanthosa Grishin, gen. n. (TS: Charmona xanthosa Stichel, 1910) is proposed for a sister lineage of Sertania Callaghan & Kaminski, 2017 and Befrostia Grishin, gen. n. (TS: Emesis elegia Stichel, 1929) is proposed for a clade without apparent phylogenetic affinities that we place in Befrostiini Grishin, trib. n. In conclusion, genomic data reveal a number of errors in the current classification of Emesidini and allow us to confidently reclassify the tribe partitioning it in three genera: Apodemia, Curvie gen. n. and Emesis.

Three new subfamilies of skipper butterflies (Lepidoptera, Hesperiidae)

We obtained and analyzed whole genome data for more than 160 representatives of skipper butterflies (family Hesperiidae) from all known subfamilies, tribes and most distinctive genera. We found that two genera, Katreus Watson, 1893 and Ortholexis Karsch, 1895, which are sisters, are well-separated from all other major phylogenetic lineages and originate near the base of the Hesperiidae tree, prior to the origin of some subfamilies. Due to this ancient origin compared to other subfamilies, this group is described as Katreinae Grishin, subfam. n. DNA sequencing of primary type specimens reveals that Ortholexismelichroptera Karsch, 1895 is not a female of Ortholexisholocausta Mabille, 1891, but instead a female of Ortholexisdimidia Holland, 1896. This finding establishes O.dimidia as a junior subjective synonym of O.melichroptera. Furthermore, we see that Chamunda Evans, 1949 does not originate within Pyrginae Burmeister, 1878, but, unexpectedly, forms an ancient lineage of its own at the subfamily rank: Chamundinae Grishin, subfam. n. Finally, a group of two sister genera, Barca de Nicéville, 1902 and Apostictopterus Leech, [1893], originates around the time Hesperiinae Latreille, 1809 have split from their sister clade. A new subfamily Barcinae Grishin, subfam. n. sets them apart from all other Hesperiidae.

Whole Genome Shotgun Phylogenomics Resolves the Pattern and Timing of Swallowtail Butterfly Evolution

Evolutionary relationships have remained unresolved in many well-studied groups, even though advances in next-generation sequencing and analysis, using approaches such as transcriptomics, anchored hybrid enrichment, or ultraconserved elements, have brought systematics to the brink of whole genome phylogenomics. Recently, it has become possible to sequence the entire genomes of numerous nonbiological models in parallel at reasonable cost, particularly with shotgun sequencing. Here, we identify orthologous coding sequences from whole-genome shotgun sequences, which we then use to investigate the relevance and power of phylogenomic relationship inference and time-calibrated tree estimation. We study an iconic group of butterflies—swallowtails of the family Papilionidae—that has remained phylogenetically unresolved, with continued debate about the timing of their diversification. Low-coverage whole genomes were obtained using Illumina shotgun sequencing for all genera. Genome assembly coupled to BLAST-based orthology searches allowed extraction of 6621 orthologous protein-coding genes for 45 Papilionidae species and 16 outgroup species (with 32% missing data after cleaning phases). Supermatrix phylogenomic analyses were performed with both maximum-likelihood (IQ-TREE) and Bayesian mixture models (PhyloBayes) for amino acid sequences, which produced a fully resolved phylogeny providing new insights into controversial relationships. Species tree reconstruction from gene trees was performed with ASTRAL and SuperTriplets and recovered the same phylogeny. We estimated gene site concordant factors to complement traditional node-support measures, which strengthens the robustness of inferred phylogenies. Bayesian estimates of divergence times based on a reduced data set (760 orthologs and 12% missing data) indicate a mid-Cretaceous origin of Papilionoidea around 99.2 Ma (95% credibility interval: 68.6–142.7 Ma) and Papilionidae around 71.4 Ma (49.8–103.6 Ma), with subsequent diversification of modern lineages well after the Cretaceous-Paleogene event. These results show that shotgun sequencing of whole genomes, even when highly fragmented, represents a powerful approach to phylogenomics and molecular dating in a group that has previously been refractory to resolution.

Genome survey sequencing for the characterization of genetic background of Dracaena cambodiana and its defense response during dragon's blood formation

Dragon's blood collected from the genus Dracaena is used as a renowned traditional medicine in various cultures worldwide. However, the genetics of the genus Dracaena and the formation mechanism of dragon's blood remain poorly understood. Here, we generate the first draft genome reference assembly of an elite Chinese Dracaena species, Dracaena cambodiana, from next-generation sequencing data with 89.46× coverage. The reads were assembled into 2,640,704 contigs with an N50 length of 1.87 kb, and a 1.05 Gb assembly was finally assembled with 2,379,659 scaffolds. Furthermore, 97.75% of the 267,243 simple sequence repeats identified from these scaffolds were mononucleotide, dinucleotide, and trinucleotide repeats. Among all 53,700 predicted genes, 158 genes involved in cell wall and plant hormone synthesis and reactive oxygen species scavenging showed altered regulation during the formation of dragon's blood. This study provides a genomic characterization of D. cambodiana and improves understanding of the molecular mechanism of dragon's blood formation. This report represents the first genome-wide characterization of a Dracaena species in the Asparagaceae.

Comparative analysis of swallowtail transcriptomes suggests molecular determinants for speciation and adaptation

Genetic determinants of speciation in closely related species are poorly understood. We sequenced and analyzed transcriptomes of swallowtail butterflies Heraclides cresphontes (northeastern species) and Heraclides rumiko (southwestern species), a pair of mostly allopatric sister species whose distribution ranges overlap narrowly in central Texas. We found that the two swallowtails confidently differ (FST > 0.5 for both species) in about 5% of genes, similarly to the divergence in another pair of swallowtail species Pterourus glaucus (southern species) and Pterourus canadensis (northern species). The same genes tend to diverge in both species pairs, suggesting similar speciation paths in Heraclides and Pterourus. The most significant differences for both species pairs were found in the circadian clock genes that were conserved within each species and diverged strongly between species (P-value < 0.01 and FST > 0.7). This divergence implied that adaptations to different climates and photoperiod at different latitudes or differences in mating behavior, including mating time and copulation duration, may be possible factors in ecological or behavioral-based speciation. Finally, we suggest several nuclear DNA regions that consistently and prominently differ between the sister swallowtail species as nuclear barcodes for swallowtail identification, with the best barcode being an exon from the protein TIMELESS.

The Bear Giant-Skipper genome suggests genetic adaptations to living inside yucca roots

Giant-Skippers (Megathymini) are unusual thick-bodied, moth-like butterflies whose caterpillars feed inside Yucca roots and Agave leaves. Giant-Skippers are attributed to the subfamily Hesperiinae and they are endemic to southern and mostly desert regions of the North American continent. To shed light on the genotypic determinants of their unusual phenotypic traits, we sequenced and annotated a draft genome of the largest Giant-Skipper species, the Bear (Megathymus ursus violae). The Bear skipper genome is the least heterozygous among sequenced Lepidoptera genomes, possibly due to much smaller population size and extensive inbreeding. Their lower heterozygosity helped us to obtain a high-quality genome with an N50 of 4.2 Mbp. The ~ 430 Mb genome encodes about 14000 proteins. Phylogenetic analysis supports placement of Giant-Skippers with Grass-Skippers (Hesperiinae). We find that proteins involved in odorant and taste sensing as well as in oxidative reactions have diverged significantly in Megathymus as compared to Lerema, another Grass-Skipper. In addition, the Giant-Skipper has lost several odorant and gustatory receptors and possesses many fewer (1/3-1/2 of other skippers) anti-oxidative enzymes. Such differences may be related to the unusual life style of Giant-Skippers: they do not feed as adults, and their caterpillars feed inside Yuccas and Agaves, which provide a source of antioxidants such as polyphenols.

The analysis of genetic variation in the mitochondrial genome and its application for the identification of Papilio species

Mitochondrial DNA (mtDNA) markers are ideal for evolutionary studies, including phylogeography, population genetics, phylogeny, etc. However, different mitochondrial genes always own different evolutionary rate. In this study, we analysed the genetic variation across the 16 complete mtDNA from 13 species in the genus Papilio and recognized the best DNA barcoding for Papilio species. The mitochondrial gene arrangement for each species shares a similar order, similar to the typical Papilionidae species, which indicated the relatively conservative state of gene arrangement in Papilio. The sliding window of genetic diversity showed that there was a significant difference in the genetic diversity of each gene in the mitochondrial genome of Papilio. The relatively mean clock rate of the ND1 was broadly lower than the other genes in mitochondrial genome of Papilio; while the ATP8 owns the largest values of mean clock rate. Those results suggested that the rate of evolution of each gene is not balanced and all mitochondrial genes except ND1 and ATP8 could act as barcoding for the identification of Papilio species. The phylogenetic analyses of complete mtDNA data for 13 Papilio species divided them into five major branches, which keep the same topological structure with previous studies.

The role of latitudinal, genetic and temperature variation in the induction of diapause of Papilio glaucus (Lepidoptera: Papilionidae)

A key adaptation in insects for dealing with variable environmental conditions is the ability to diapause. The tiger swallowtail butterflies, Papilio glaucus and P. canadensis are ideal species to explore the genetic causes and population genetic consequences of diapause because divergence in this trait is believed to be a salient factor in maintaining a hybrid zone between these species. Yet little is known about the factors that influence diapause induction in this system. Here we explored how spatial (latitudinal), environmental (temperature) and genetic (hybridization) factors affect diapause induction in this system. Specifically, a series of growth chamber experiments using wild caught individuals from across the eastern United States were performed to: (1) evaluate how critical photoperiod varies with latitude, (2) isolate the stage in which induction occurs, (3) test whether changes in temperature affected rates of diapause induction, and (4) explore how the incidence of diapause is affected in hybrid offspring. We find that induction occurs in the larval stage, is not sensitive to a relatively broad range of temperatures, appears to have a complex genetic basis (i.e., is not simply a dominant trait following a Mendelian inheritance pattern) and that the critical photoperiod increases by 0.4 h with each increasing degree in latitude. This work deepens our understanding of how spatial, environmental and genetic variation influences a key seasonal adaptation (diapause induction) in a well-developed ecological model system and will make possible future studies that explore how climatic variation affects the population dynamics and genetics of this system.

Climate-mediated hybrid zone movement revealed with genomics, museum collection, and simulation modeling

Climate-mediated changes in hybridization will dramatically alter the genetic diversity, adaptive capacity, and evolutionary trajectory of interbreeding species. Our ability to predict the consequences of such changes will be key to future conservation and management decisions. Here we tested through simulations how recent warming (over the course of a 32-y period) is affecting the geographic extent of a climate-mediated developmental threshold implicated in maintaining a butterfly hybrid zone (Papilio glaucus and Papilio canadensis; Lepidoptera: Papilionidae). These simulations predict a 68-km shift of this hybrid zone. To empirically test this prediction, we assessed genetic and phenotypic changes using contemporary and museum collections and document a 40-km northward shift of this hybrid zone. Interactions between the two species appear relatively unchanged during hybrid zone movement. We found no change in the frequency of hybridization, and regions of the genome that experience little to no introgression moved largely in concert with the shifting hybrid zone. Model predictions based on climate scenarios predict this hybrid zone will continue to move northward, but with substantial spatial heterogeneity in the velocity (55-144 km/1 °C), shape, and contiguity of movement. Our findings suggest that the presence of nonclimatic barriers (e.g., genetic incompatibilities) and/or nonlinear responses to climatic gradients may preserve species boundaries as the species shift. Further, we show that variation in the geography of hybrid zone movement could result in evolutionary responses that differ for geographically distinct populations spanning hybrid zones, and thus have implications for the conservation and management of genetic diversity.

Current Status of the Blue Butterfly in Fukushima Research

Adverse biological impacts of the Fukushima nuclear accident have been revealed using the pale grass blue butterfly, Zizeeria maha, since 2012, which were often considered incompatible with the conventional understanding of radiation biology. This discrepancy likely originates from different system conditions and methodologies. In this article, we first respond to comments from the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) regarding our study; "technical errors" in unit usage and mathematical models noted by UNSCEAR are not errors but reflect our research philosophy not to introduce theoretical assumptions associated with unit conversion and mathematical fit. Second, we review our recent studies to support the original 2012 conclusions. Because the high morphological abnormality rate and small body size detected in Fukushima in 2011 have already ceased, likely through adaptive evolution, their present geographical distributions were investigated throughout Japan. Local populations showing relatively high abnormality rates and small body sizes were rare and basically restricted to Miyagi and its northern populations excluding the Fukushima populations, supporting the causal involvement of the accident. Lastly, we stress the importance of understanding the whole picture of the biological impacts of the Fukushima accident. In addition to the direct radiation impacts, indirect impacts through unknown radiation-associated mechanisms, such as immunological responses to insoluble particulate matter and nutritional deficiencies in plants and animals, would be in effect. Further environmental studies beyond conventional radiation biology and physics are necessary to understand the complex responses of organisms, including humans, to the Fukushima nuclear accident.

Lepidoptera genomes: current knowledge, gaps and future directions

Butterflies and moths (Lepidoptera) are one of the most ecologically diverse and speciose insect orders. With recent advances in genomics, new Lepidoptera genomes are regularly being sequenced, and many of them are playing principal roles in genomics studies, particularly in the fields of phylo-genomics and functional genomics. Thus far, assembled genomes are only available for <10 of the 43 Lepidoptera superfamilies. Nearly all are model species, found in the speciose clade Ditrysia. Community support for Lepidoptera genomics is growing with successful management and dissemination of data and analytical tools in centralized databases. With genomic studies quickly becoming integrated with ecological and evolutionary research, the Lepidoptera community will unquestionably benefit from new high-quality reference genomes that are more evenly distributed throughout the order.

Wolbachia in the Genus Bicyclus: a Forgotten Player

Bicyclus butterflies are key species for studies of wing pattern development, phenotypic plasticity, speciation and the genetics of Lepidoptera. One of the key endosymbionts in butterflies, the alpha-Proteobacterium Wolbachia pipientis, is affecting many of these biological processes; however, Bicyclus butterflies have not been investigated systematically as hosts to Wolbachia. In this study, we screen for Wolbachia infection in several Bicyclus species from natural populations across Africa as well as two laboratory populations. Out of the 24 species tested, 19 were found to be infected, and no double infection was found, but both A- and B-supergroup strains colonise this butterfly group. We also show that many of the Wolbachia strains identified in Bicyclus butterflies belong to the ST19 clonal complex. We discuss the importance of our results in regard to routinely screening for Wolbachia when using Bicyclus butterflies as the study organism of research in eco-evolutionary biology.

Bayesian Analysis of Evolutionary Divergence with Genomic Data under Diverse Demographic Models

We present a new Bayesian method for estimating demographic and phylogenetic history using population genomic data. Several key innovations are introduced that allow the study of diverse models within an Isolation-with-Migration framework. The new method implements a 2-step analysis, with an initial Markov chain Monte Carlo (MCMC) phase that samples simple coalescent trees, followed by the calculation of the joint posterior density for the parameters of a demographic model. In step 1, the MCMC sampling phase, the method uses a reduced state space, consisting of coalescent trees without migration paths, and a simple importance sampling distribution without the demography of interest. Once obtained, a single sample of trees can be used in step 2 to calculate the joint posterior density for model parameters under multiple diverse demographic models, without having to repeat MCMC runs. Because migration paths are not included in the state space of the MCMC phase, but rather are handled by analytic integration in step 2 of the analysis, the method is scalable to a large number of loci with excellent MCMC mixing properties. With an implementation of the new method in the computer program MIST, we demonstrate the method's accuracy, scalability, and other advantages using simulated data and DNA sequences of two common chimpanzee subspecies: Pan troglodytes (P. t.) troglodytes and P. t. verus.

Complete Genome of Achalarus lyciades, The First Representative of the Eudaminae Subfamily of Skippers

Background:

The Hoary Edge Skipper (Achalarus lyciades) is an eastern North America endemic butterfly from the Eudaminae subfamily of skippers named for an underside whitish patch near the hindwing edge. Its caterpillars feed on legumes, in contrast to Grass skippers (subfamily Hesperiinae) which feed exclusively on monocots.

Results:

To better understand the evolution and phenotypic diversification of Skippers (family Hesperiidae), we sequenced, assembled and annotated a complete genome draft and transcriptome of a wild-caught specimen of A. lyciades and compared it with the available genome of the Clouded Skipper (Lerema accius) from the Grass skipper subfamily. The genome of A. lyciades is nearly twice the size of L. accius (567 Mbp vs. 298 Mbp), however it encodes a smaller number of proteins (15881 vs. 17411). Gene expansions we identified previously in L. accius apparently did not occur in the genome of A. lyciades. For instance, a family of hypothetical cellulases that diverged from an endochitinase (possibly associated with feeding of L. accius caterpillars on nutrient-poor grasses) is absent in A. lyciades. While L. accius underwent gene expansion in pheromone binding proteins, A. lyciades has more opsins. This difference may be related to the mate recognition mechanisms of the two species: visual cues might be more important for the Eudaminae skippers (which have more variable wing patterns), whereas odor might be more important for Grass skippers (that are hardly distinguishable by their wings). Phylogenetically, A. lyciades is a sister species of L. accius, the only other Hesperiidae with a complete genome.

Conclusions:

A new reference genome of a dicot-feeding skippers, the first from the Eudaminae subfamily, reveals its larger size and suggests hypotheses about phenotypic traits and differences from monocot-feeding skippers.

Nuclear genomes distinguish cryptic species suggested by their DNA barcodes and ecology

DNA sequencing brings another dimension to exploration of biodiversity, and large-scale mitochondrial DNA cytochrome oxidase I barcoding has exposed many potential new cryptic species. Here, we add complete nuclear genome sequencing to DNA barcoding, ecological distribution, natural history, and subtleties of adult color pattern and size to show that a widespread neotropical skipper butterfly known as Udranomia kikkawai (Weeks) comprises three different species in Costa Rica. Full-length barcodes obtained from all three century-old Venezuelan syntypes of U. kikkawai show that it is a rainforest species occurring from Costa Rica to Brazil. The two new species are Udranomia sallydaleyae Burns, a dry forest denizen occurring from Costa Rica to Mexico, and Udranomia tomdaleyi Burns, which occupies the junction between the rainforest and dry forest and currently is known only from Costa Rica. Whereas the three species are cryptic, differing but slightly in appearance, their complete nuclear genomes totaling 15 million aligned positions reveal significant differences consistent with their 0.00065-Mbp (million base pair) mitochondrial barcodes and their ecological diversification. DNA barcoding of tropical insects reared by a massive inventory suggests that the presence of cryptic species is a widespread phenomenon and that further studies will substantially increase current estimates of insect species richness.

A high-coverage draft genome of the mycalesine butterfly Bicyclus anynana

The mycalesine butterfly Bicyclus anynana, the "Squinting bush brown," is a model organism in the study of lepidopteran ecology, development, and evolution. Here, we present a draft genome sequence for B. anynana to serve as a genomics resource for current and future studies of this important model species. Seven libraries with insert sizes ranging from 350 bp to 20 kb were constructed using DNA from an inbred female and sequenced using both Illumina and PacBio technology; 128 Gb of raw Illumina data was filtered to 124 Gb and assembled to a final size of 475 Mb (∼×260 assembly coverage). Contigs were scaffolded using mate-pair, transcriptome, and PacBio data into 10 800 sequences with an N50 of 638 kb (longest scaffold 5 Mb). The genome is comprised of 26% repetitive elements and encodes a total of 22 642 predicted protein-coding genes. Recovery of a BUSCO set of core metazoan genes was almost complete (98%). Overall, these metrics compare well with other recently published lepidopteran genomes. We report a high-quality draft genome sequence for Bicyclus anynana. The genome assembly and annotated gene models are available at LepBase (http://ensembl.lepbase.org/index.html).

Novel microsatellite markers for the oriental fruit moth Grapholita molesta (Lepidoptera: Tortricidae) and effects of null alleles on population genetics analyses

The oriental fruit moth (OFM) Grapholita molesta (Lepidoptera: Tortricidae) is an important economic pest of stone and pome fruits worldwide. We sequenced the OFM genome using next-generation sequencing and characterized the microsatellite distribution. In total, 56,674 microsatellites were identified, with 11,584 loci suitable for primer design. Twenty-seven polymorphic microsatellites, including 24 loci with trinucleotide repeat and three with pentanucleotide repeat, were validated in 95 individuals from four natural populations. The allele numbers ranged from 4 to 40, with an average value of 13.7 per locus. A high frequency of null alleles was observed in most loci developed for the OFM. Three marker panels, all of the loci, nine loci with the lowest null allele frequencies, and nine loci with the highest null allele frequencies, were established for population genetics analyses. The null allele influenced estimations of genetic diversity parameters but not the OFM's genetic structure. Both a STRUCTURE analysis and a discriminant analysis of principal components, using the three marker panels, divided the four natural populations into three groups. However, more individuals were incorrectly assigned by the STRUCTURE analysis when the marker panel with the highest null allele frequency was used compared with the other two panels. Our study provides empirical research on the effects of null alleles on population genetics analyses. The microsatellites developed will be valuable markers for genetic studies of the OFM.

Mitogenomes of Giant-Skipper Butterflies reveal an ancient split between deep and shallow root feeders

Background: Giant-Skipper butterflies from the genus Megathymus are North American endemics. These large and thick-bodied Skippers resemble moths and are unique in their life cycles. Grub-like at the later stages of development, caterpillars of these species feed and live inside yucca roots. Adults do not feed and are mostly local, not straying far from the patches of yucca plants. Methods: Pieces of muscle were dissected from the thorax of specimens and genomic DNA was extracted (also from the abdomen of a specimen collected nearly 60 years ago). Paired-end libraries were prepared and sequenced for 150bp from both ends. The mitogenomes were assembled from the reads followed by a manual gap-closing procedure and a phylogenetic tree was constructed using a maximum likelihood method from an alignment of the mitogenomes. Results: We determined mitogenome sequences of nominal subspecies of all five known species of Megathymus and Agathymus mariae to confidently root the phylogenetic tree. Pairwise sequence identity indicates the high similarity, ranging from 88-96% among coding regions for 13 proteins, 22 tRNAs and 2 rRNA, with a gene order typical for mitogenomes of Lepidoptera. Phylogenetic analysis confirms that Giant-Skippers (Megathymini) originate within the subfamily Hesperiinae and do not warrant a subfamily rank. Genus Megathymus is monophyletic and splits into two species groups. M. streckeri and M. cofaqui caterpillars feed deep in the main root system of yucca plants and deposit frass underground. M. ursus, M. beulahae and M. yuccae feed in the yucca caudex and roots near the ground, and deposit frass outside through a "tent" (a silk tube projecting from the center of yucca plant). M. yuccae and M. beulahae are sister species consistently with morphological similarities between them. Conclusions: We constructed the first DNA-based phylogeny of the genus Megathymus from their mitogenomes. The phylogeny agrees with morphological considerations.

Genetic basis of allochronic differentiation in the fall armyworm

BACKGROUND

Very little is known on how changes in circadian rhythms evolve. The noctuid moth Spodoptera frugiperda (Lepidoptera: Noctuidae) consists of two strains that exhibit allochronic differentiation in their mating time, which acts as a premating isolation barrier between the strains. We investigated the genetic basis of the strain-specific timing differences to identify the molecular mechanisms of differentiation in circadian rhythms.

RESULTS

Through QTL analyses we identified one major Quantitative trait chromosome (QTC) underlying differentiation in circadian timing of mating activity. Using RADtags, we identified this QTC to be homologous to Bombyx mori C27, on which the clock gene vrille is located, which thus became the major candidate gene. In S. frugiperda, vrille showed strain-specific polymorphisms. Also, vrille expression differed significantly between the strains, with the rice-strain showing higher expression levels than the corn-strain. In addition, RT-qPCR experiments with the other main clock genes showed that pdp1, antagonist of vrille in the modulatory feedback loop of the circadian clock, showed higher expression levels in the rice-strain than in the corn-strain.

CONCLUSIONS

Together, our results indicate that the allochronic differentiation in the two strains of S. frugiperda is associated with differential transcription of vrille or a cis-acting gene close to vrille, which contributes to the evolution of prezygotic isolation in S. frugiperda.

When COI barcodes deceive: complete genomes reveal introgression in hairstreaks

Two species of hairstreak butterflies from the genus Calycopis are known in the United States: C. cecrops and C. isobeon Analysis of mitochondrial COI barcodes of Calycopis revealed cecrops-like specimens from the eastern US with atypical barcodes that were 2.6% different from either USA species, but similar to Central American Calycopis species. To address the possibility that the specimens with atypical barcodes represent an undescribed cryptic species, we sequenced complete genomes of 27 Calycopis specimens of four species: C. cecrops, C. isobeon, C. quintana and C. bactra Some of these specimens were collected up to 60 years ago and preserved dry in museum collections, but nonetheless produced genomes as complete as fresh samples. Phylogenetic trees reconstructed using the whole mitochondrial and nuclear genomes were incongruent. While USA Calycopis with atypical barcodes grouped with Central American species C. quintana by mitochondria, nuclear genome trees placed them within typical USA C. cecrops in agreement with morphology, suggesting mitochondrial introgression. Nuclear genomes also show introgression, especially between C. cecrops and C. isobeon About 2.3% of each C. cecrops genome has probably (p-value < 0.01, FDR < 0.1) introgressed from C. isobeon and about 3.4% of each C. isobeon genome may have come from C. cecrops. The introgressed regions are enriched in genes encoding transmembrane proteins, mitochondria-targeting proteins and components of the larval cuticle. This study provides the first example of mitochondrial introgression in Lepidoptera supported by complete genome sequencing. Our results caution about relying solely on COI barcodes and mitochondrial DNA for species identification or discovery.

Complete genome of Pieris rapae, a resilient alien, a cabbage pest, and a source of anti-cancer proteins

The Small Cabbage White ( Pieris rapae) is originally a Eurasian butterfly. Being accidentally introduced into North America, Australia, and New Zealand a century or more ago, it spread throughout the continents and rapidly established as one of the most abundant butterfly species. Although it is a serious pest of cabbage and other mustard family plants with its caterpillars reducing crops to stems, it is also a source of pierisin, a protein unique to the Whites that shows cytotoxicity to cancer cells. To better understand the unusual biology of this omnipresent agriculturally and medically important butterfly, we sequenced and annotated the complete genome from USA specimens. At 246 Mbp, it is among the smallest Lepidoptera genomes reported to date. While 1.5% positions in the genome are heterozygous, they are distributed highly non-randomly along the scaffolds, and nearly 20% of longer than 1000 base-pair segments are SNP-free (median length: 38000 bp). Computational simulations of population evolutionary history suggest that American populations started from a very small number of introduced individuals, possibly a single fertilized female, which is in agreement with historical literature. Comparison to other Lepidoptera genomes reveals several unique families of proteins that may contribute to the unusual resilience of Pieris. The nitrile-specifier proteins divert the plant defense chemicals to non-toxic products. The apoptosis-inducing pierisins could offer a defense mechanism against parasitic wasps. While only two pierisins from Pieris rapae were characterized before, the genome sequence revealed eight, offering additional candidates as anti-cancer drugs. The reference genome we obtained lays the foundation for future studies of the Cabbage White and other Pieridae species.

Odonata (dragonflies and damselflies) as a bridge between ecology and evolutionary genomics

Odonata (dragonflies and damselflies) present an unparalleled insect model to integrate evolutionary genomics with ecology for the study of insect evolution. Key features of Odonata include their ancient phylogenetic position, extensive phenotypic and ecological diversity, several unique evolutionary innovations, ease of study in the wild and usefulness as bioindicators for freshwater ecosystems worldwide. In this review, we synthesize studies on the evolution, ecology and physiology of odonates, highlighting those areas where the integration of ecology with genomics would yield significant insights into the evolutionary processes that would not be gained easily by working on other animal groups. We argue that the unique features of this group combined with their complex life cycle, flight behaviour, diversity in ecological niches and their sensitivity to anthropogenic change make odonates a promising and fruitful taxon for genomics focused research. Future areas of research that deserve increased attention are also briefly outlined.