A checklist of European butterfly larval foodplants

Butterflies are charismatic insects and have been well studied, particularly in Europe. They are disproportionately used in generating and testing hypotheses; on everything from general evolutionary processes, such as speciation or host association dynamics; to conservation-related studies, such as climate change or habitat loss. Accurate lists of the larval foodplants for European butterflies are not readily available. Mistakes are propagated and information cannot be checked for accuracy. The level of evidence is unknown, and how usage varies between countries is poorly understood. The study consulted 1119 references to produce 19,488 records of larval foodplants for European butterflies. This resulted in 5589 larval host plant records for 464 European butterfly species, with multiple references, enabling information to be checked. Information was unavailable for 59 species. The level of evidence for each relationship shows the current state of knowledge. Significant issues were identified for 3.9% of records extracted from references due to mistakes, ambiguous or unknown plant names, distribution issues, resulting in information being lost. Plants with questionable distributions suggest either mis-identification or species that have been split. Little is known about plant usage in Eastern Europe. The larval foodplants of many monophagous and Satyrinae butterflies are poorly studied. Only 63% of threatened 2010 Red Listed butterflies have reliable host plant records. The study has provided ecologists with a valuable resource, of a more accurate checklist of the larval foodplants for each European country. Why plant usage varies over a butterfly's distribution opens up some interesting research questions.

Mitogenomic phylogeny of nymphalid subfamilies confirms the basal clade position of Danainae (Insecta: Lepidoptera: Nymphalidae)

The phylogenetic relationships among the nymphalid subfamilies have largely been resolved using both morphological and molecular datasets, with the exception of a conflicting basal clade position for Libytheinae or Danainae that remains contentious between morphological and molecular studies. Several phylogenomic analyses have found that the danaine clade is sister to other nymphalid subfamilies; however, it largely depends on utilizing different molecular datasets, analysis methods, and taxon sampling. This study aimed to resolve the basal clade position and relationships among subfamilies and tribes of Nymphalinae by combining the most comprehensive available mitogenomic datasets with various analyses methods by incorporating a new Symbrenthia lilaea Hewitson sequence data. Phylogenetic relationships among 11 nymphalid subfamilies and the tribes of Nymphalinae were inferred by combining new and available mitogenomic sequence data from 80 ingroup and six outgroup species. The phylogenetic trees were reconstructed using maximum-likelihood (ML) and Bayesian inference (BI) methods based on five concatenated datasets: amino acid sequences and nucleotides from different combinations of protein-coding genes (PCGs), ribosomal RNA (rRNAs), and transfer RNA (tRNAs). Danainae is well-supported as the basal clade and sister to the remaining nymphalid subfamilies, except for the paraphyletic Libytheinae. Libytheinae was either recovered as a sister to the danaine clade followed by the satyrine clade or sister to the nymphaline + heliconiine clades, and is consistent with recent phylogenetic studies on Nymphalidae. The monophyletic Nymphalinae has been recovered in all analyses and resolves tribal-level relationships with high support values in both BI and ML analyses. We supported the monophyletic Nymphalini as a sister clade to Victorini, Melitaeini, and Kallimini + Junoniini with high supporting values in BI and ML analyses, which is consistent with previously published morphological and molecular studies.

One Species, Hundreds of Subspecies? New Insight into the Intraspecific Classification of the Old World Swallowtail (Papilio machaon Linnaeus, 1758) Based on Two Mitochondrial DNA Markers

The Old World swallowtail Papilio machaon Linnaeus, 1758 is one of the most well-known and most characteristic members of the family Papilionidae. Over the past two centuries, the butterfly has been the subject of many studies. P. machaon is characterised by a tendency to change the wing colour pattern. In turn, due to the great interest of collectors and amateur entomologists, these studies have been converted into the description of over 100 colour forms, aberrations and subspecies. In this study, mitochondrial DNA (mtDNA), 16S rDNA and cytochrome b sequences were used to examine the correlation between the intraspecific classification and genetic structure of P. machaon. The study used 87 specimens from 59 different localities covering the geographic distribution of this species in the Palaearctic. The phylogenetic relationships within and between the Old World swallowtail subspecies showed that the intraspecific classification proposed by various authors does not correlate with the variability in mitochondrial DNA sequences. In addition, populations occurring at the species distribution borders in the Palaearctic Region (i.e., Japan, Kamchatka, Morocco and Sakhalin) are genetically distinct from other species.

De novo genome assemblies of butterflies

BACKGROUND

The availability of thousands of genomes has enabled new advancements in biology. However, many genomes have not been investigated for their quality. Here we examine quality trends in a taxonomically diverse and well-known group, butterflies (Papilionoidea), and provide draft, de novo assemblies for all available butterfly genomes. Owing to massive genome sequencing investment and taxonomic curation, this is an excellent group to explore genome quality.

FINDINGS

We provide de novo assemblies for all 822 available butterfly genomes and interpret their quality in terms of completeness and continuity. We identify the 50 highest quality genomes across butterflies and conclude that the ringlet, Aphantopus hyperantus, has the highest quality genome. Our post-processing of draft genome assemblies identified 118 butterfly genomes that should not be reused owing to contamination or extremely low quality. However, many draft genomes are of high utility, especially because permissibility of low-quality genomes is dependent on the objective of the study. Our assemblies will serve as a key resource for papilionid genomics, especially for researchers without computational resources.

CONCLUSIONS

Quality metrics and assemblies are typically presented with annotated genome accessions but rarely with de novo genomes. We recommend that studies presenting genome sequences provide the assembly and some metrics of quality because quality will significantly affect downstream results. Transparency in quality metrics is needed to improve the field of genome science and encourage data reuse.

Composition and diversity of butterflies (Lepidoptera, Papilionoidea) along an atmospheric pollution gradient in the Monterrey Metropolitan Area, Mexico

This study compares the variation of richness, abundance and diversity of butterfly species along an atmospheric pollution gradient and during different seasons in the Monterrey Metropolitan Area, Mexico. Likewise, we analyse the influence of environmental variables on the abundance and richness of butterfly species and quantify the indicator species for each atmospheric pollution category. Based on spatial analysis of the main atmospheric pollutants and the vegetation cover conditions, four permanent sampling sites were delimited. The sampling was carried out monthly in each of the sites using aerial entomological nets and ten Van Someren-Rydon traps during May 2018 to April 2019. A total of 8,570 specimens belonging to six families and 209 species were collected. Both species richness and abundance were significantly different between all sites, except for the comparison between the moderate contamination site and the high contamination site; diversity decreased significantly with increasing levels of contamination. The seasonality effect was absent on species richness; however, for species abundance the differences between dry season and rainy season were significant in each site excepting the moderate contamination site. Regarding diversity, the seasonal effect showed different distribution patterns according to each order. Relative humidity, vegetation cover and three pollution variables were highly correlated with both abundance and species richness. From the total number of species found, only 47 had a significant indicator value. This study constitutes the first faunistic contribution of butterflies as indicators of the environmental quality of urban areas in Mexico, which will help in the development of strategies for the management, planning and conservation of urban biodiversity.

It's a moth! It's a butterfly! It's the complete mitochondrial genome of the American moth-butterfly Macrosoma conifera (Warren, 1897) (Insecta: Lepidoptera: Hedylidae)!

The taxonomic placement of the moth-butterfly, Macrosoma conifera (Warren 1897) (Lepidoptera: Hedylidae), has been controversial. The 15,344 bp complete M. conifera circular mitogenome, assembled by genome skimming, consists of 81.7% AT nucleotides, 22 tRNAs, 13 protein-coding genes, 2 rRNAs and a control region in the typical butterfly gene order. Macrosoma conifera COX1 features an atypical CGA start codon while ATP6, COX1, COX2, and ND5 exhibit incomplete stop codons completed by the post-transcriptional addition of 3' A residues. Phylogenetic reconstruction places M. conifera as sister to the skippers (Hesperiidae), which is consistent with several recent phylogenetic analyses.

Priors and Posteriors in Bayesian Timing of Divergence Analyses: The Age of Butterflies Revisited

The need for robust estimates of times of divergence is essential for downstream analyses, yet assessing this robustness is still rare. We generated a time-calibrated genus-level phylogeny of butterflies (Papilionoidea), including 994 taxa, up to 10 gene fragments and an unprecedented set of 12 fossils and 10 host-plant node calibration points. We compared marginal priors and posterior distributions to assess the relative importance of the former on the latter. This approach revealed a strong influence of the set of priors on the root age but for most calibrated nodes posterior distributions shifted from the marginal prior, indicating significant information in the molecular data set. Using a very conservative approach we estimated an origin of butterflies at 107.6 Ma, approximately equivalent to the latest Early Cretaceous, with a credibility interval ranging from 89.5 Ma (mid Late Cretaceous) to 129.5 Ma (mid Early Cretaceous). In addition, we tested the effects of changing fossil calibration priors, tree prior, different sets of calibrations and different sampling fractions but our estimate remained robust to these alternative assumptions. With 994 genera, this tree provides a comprehensive source of secondary calibrations for studies on butterflies.

Anchored phylogenomics illuminates the skipper butterfly tree of life

BACKGROUND

Butterflies (Papilionoidea) are perhaps the most charismatic insect lineage, yet phylogenetic relationships among them remain incompletely studied and controversial. This is especially true for skippers (Hesperiidae), one of the most species-rich and poorly studied butterfly families.

METHODS

To infer a robust phylogenomic hypothesis for Hesperiidae, we sequenced nearly 400 loci using Anchored Hybrid Enrichment and sampled all tribes and more than 120 genera of skippers. Molecular datasets were analyzed using maximum-likelihood, parsimony and coalescent multi-species phylogenetic methods.

RESULTS

All analyses converged on a novel, robust phylogenetic hypothesis for skippers. Different optimality criteria and methodologies recovered almost identical phylogenetic trees with strong nodal support at nearly all nodes and all taxonomic levels. Our results support Coeliadinae as the sister group to the remaining skippers, the monotypic Euschemoninae as the sister group to all other subfamilies but Coeliadinae, and the monophyly of Eudaminae plus Pyrginae. Within Pyrginae, Celaenorrhinini and Tagiadini are sister groups, the Neotropical firetips, Pyrrhopygini, are sister to all other tribes but Celaenorrhinini and Tagiadini. Achlyodini is recovered as the sister group to Carcharodini, and Erynnini as sister group to Pyrgini. Within the grass skippers (Hesperiinae), there is strong support for the monophyly of Aeromachini plus remaining Hesperiinae. The giant skippers (Agathymus and Megathymus) once classified as a subfamily, are recovered as monophyletic with strong support, but are deeply nested within Hesperiinae.

CONCLUSIONS

Anchored Hybrid Enrichment sequencing resulted in a large amount of data that built the foundation for a new, robust evolutionary tree of skippers. The newly inferred phylogenetic tree resolves long-standing systematic issues and changes our understanding of the skipper tree of life. These resultsenhance understanding of the evolution of one of the most species-rich butterfly families.

Phylogenetics of moth-like butterflies (Papilionoidea: Hedylidae) based on a new 13-locus target capture probe set

The Neotropical moth-like butterflies (Hedylidae) are perhaps the most unusual butterfly family. In addition to being species-poor, this family is predominantly nocturnal and has anti-bat ultrasound hearing organs. Evolutionary relationships among the 36 described species are largely unexplored. A new, target capture, anchored hybrid enrichment probe set ('BUTTERFLY2.0') was developed to infer relationships of hedylids and some of their butterfly relatives. The probe set includes 13 genes that have historically been used in butterfly phylogenetics. Our dataset comprised of up to 10,898 aligned base pairs from 22 hedylid species and 19 outgroups. Eleven of the thirteen loci were successfully captured from all samples, and the remaining loci were captured from ≥94% of samples. The inferred phylogeny was consistent with recent molecular studies by placing Hedylidae sister to Hesperiidae, and the tree had robust support for 80% of nodes. Our results are also consistent with morphological studies, with Macrosoma tipulata as the sister species to all remaining hedylids, followed by M. semiermis sister to the remaining species in the genus. We tested the hypothesis that nocturnality evolved once from diurnality in Hedylidae, and demonstrate that the ancestral condition was likely diurnal, with a shift to nocturnality early in the diversification of this family. The BUTTERFLY2.0 probe set includes standard butterfly phylogenetics markers, captures sequences from decades-old museum specimens, and is a cost-effective technique to infer phylogenetic relationships of the butterfly tree of life.

Two new genera of metalmark butterflies of North and Central America (Lepidoptera, Riodinidae)

Two new genera of Riodinidae (Insecta: Lepidoptera) are described, Neoapodemia Trujano-Ortega, gen. n. (Neoapodemianais (W. H. Edwards, 1876), comb. n., N.chisosensis Freeman, 1964, comb. n.) and Plesioarida Trujano-Ortega & García-Vázquez, gen. n. (Plesioaridapalmeriipalmerii (W. H. Edwards, 1870), comb. n., P.palmeriiarizona (Austin, [1989]), comb. n., P.palmeriiaustralis (Austin, [1989]), comb. n., P.hepburnihepburni (Godman & Salvin, 1886), comb. n., P.hepburniremota (Austin, 1991), comb. n., P.murphyi (Austin, [1989]), comb. n., P.hypoglaucahypoglauca (Godman & Salvin, 1878), comb. n., P.hypoglaucawellingi (Ferris, 1985), comb. n., P.walkeri (Godman & Salvin, 1886), comb. n., P.selvatica (De la Maza & De la Maza, 2017), comb. n.). Neoapodemia Trujano-Ortega, gen. n. is distributed in the southwestern USA and northeastern Mexico, while Plesioarida Trujano-Ortega & García-Vázquez, gen. n. is present from the southern USA to Central America. Species of these genera were previously classified as Apodemia C. Felder & R. Felder but molecular and morphological evidence separate them as new taxa. Morphological diagnoses and descriptions are provided for both new genera, including the main distinctive characters from labial palpi, prothoracic legs, wing venation and genitalia, as well as life history traits. A molecular phylogeny of one mitochondrial gene (COI) and two nuclear genes (EF-1a and wg) are also presented of most species of Apodemia, Neoapodemia Trujano-Ortega, gen. n., Plesioarida Trujano-Ortega & García-Vázquez, gen. n., and sequences of specimens from all tribes of Riodinidae. We compare the characters of Apodemia, Neoapodemia Trujano-Ortega, gen. n. and Plesioarida Trujano-Ortega & García-Vázquez, gen. n. and discuss the differences that support the description of these new taxa. This is a contribution to the taxonomy of the Riodinidae of North America of which the generic diversity is greater than previously recognized.

BUTTERFLIES AND PLANTS: A PHYLOGENETIC STUDY

A database on host plant records from 437 ingroup taxa has been used to test a number of hypotheses on the interaction between butterflies and their host plants using phylogenetic methods (simple character optimization, concentrated changes test, and independent contrasts test). The butterfly phylogeny was assembled from various sources and host plant clades were identified according to Chase et al.'s rbcL-based phylogeny. The ancestral host plant appears to be associated within a highly derived rosid clade, including the family Fabaceae. As fossil data suggest that this clade is older than the butterflies, they must have colonized already diversified plants. Previous studies also suggest that the patterns of association in most insect-plant interactions are more shaped by host shifts, through colonization and specialization, than by cospeciation. Consequently, we have focused explicitly on the mechanisms behind host shifts. Our results confirm, in the light of new phylogenetic evidence, the pattern reported by Ehrlich and Raven that related butterflies feed on related plants. We show that host shifts have generally been more common between closely related plants than between more distantly related plants. This finding, together with the possibility of a higher tendency of recolonizing ancestral hosts, helps to explain the apparent large-scale conservation in the patterns of association between insects and their host plants, patterns which at the same time are more flexible on a more detailed level. Plant growth form was an even more conservative aspect of the interaction between butterflies and their host plants than plant phylogeny. However, this is largely explained by a higher probability of colonizations and host shifts while feeding on trees than on other growth forms.

eButterfly: Leveraging Massive Online Citizen Science for Butterfly Consevation

Data collection, storage, analysis, visualization, and dissemination are changing rapidly due to advances in new technologies driven by computer science and universal access to the internet. These technologies and web connections place human observers front and center in citizen science-driven research and are critical in generating new discoveries and innovation in such fields as astronomy, biodiversity, and meteorology. Research projects utilizing a citizen science approach address scientific problems at regional, continental, and even global scales otherwise impossible for a single lab or even a small collection of academic researchers. Here we describe eButterfly an integrative checklist-based butterfly monitoring and database web-platform that leverages the skills and knowledge of recreational butterfly enthusiasts to create a globally accessible unified database of butterfly observations across North America. Citizen scientists, conservationists, policy makers, and scientists are using eButterfly data to better understand the biological patterns of butterfly species diversity and how environmental conditions shape these patterns in space and time. eButterfly in collaboration with thousands of butterfly enthusiasts has created a near real-time butterfly data resource producing tens of thousands of observations per year open to all to share and explore.

The evolutionary convergence of mid-Mesozoic lacewings and Cenozoic butterflies

Mid-Mesozoic kalligrammatid lacewings (Neuroptera) entered the fossil record 165 million years ago (Ma) and disappeared 45 Ma later. Extant papilionoid butterflies (Lepidoptera) probably originated 80–70 Ma, long after kalligrammatids became extinct. Although poor preservation of kalligrammatid fossils previously prevented their detailed morphological and ecological characterization, we examine new, well-preserved, kalligrammatid fossils from Middle Jurassic and Early Cretaceous sites in northeastern China to unravel a surprising array of similar morphological and ecological features in these two, unrelated clades. We used polarized light and epifluorescence photography, SEM imaging, energy dispersive spectrometry and time-of-flight secondary ion mass spectrometry to examine kalligrammatid fossils and their environment. We mapped the evolution of specific traits onto a kalligrammatid phylogeny and discovered that these extinct lacewings convergently evolved wing eyespots that possibly contained melanin, and wing scales, elongate tubular proboscides, similar feeding styles, and seed–plant associations, similar to butterflies. Long-proboscid kalligrammatid lacewings lived in ecosystems with gymnosperm–insect relationships and likely accessed bennettitalean pollination drops and pollen. This system later was replaced by mid-Cretaceous angiosperms and their insect pollinators.

Species delimitation in the Grayling genus Pseudochazara (Lepidoptera, Nymphalidae, Satyrinae) supported by DNA barcodes

The Palaearctic Grayling genus Pseudochazara encompasses a number of petrophilous butterfly species, most of which are local endemics especially in their centre of radiation in SW Asia and the Balkans. Due to a lack of consistent morphological characters, coupled with habitat induced variability, their taxonomy is poorly understood and species delimitation is hampered. We employed a DNA barcoding approach to address the question of separate species status for several European taxa and provide first insight into the phylogeny of the genus. Unexpectedly we found conflicting patterns with deep divergences between presumably conspecific taxa and lack of divergence among well-defined species. We propose separate species status for Pseudochazara tisiphone, Pseudochazara amalthea, Pseudochazara amymone, and Pseudochazara kermana all of which have separate well supported clades, with the majority of them becoming local endemics. Lack of resolution in the 'Mamurra' species group with well-defined species (in terms of wing pattern and coloration) such as Pseudochazara geyeri, Pseudochazara daghestana and Pseudochazara alpina should be further explored using nuclear molecular markers with higher genetic resolution.

Complete mitochondrial genomes of five skippers (Lepidoptera: Hesperiidae) and phylogenetic reconstruction of Lepidoptera

We sequenced mitogenomes of five skippers (family Hesperiidae, Lepidoptera) to obtain further insight into the characteristics of butterfly mitogenomes and performed phylogenetic reconstruction using all available gene sequences (PCGs, rRNAs, and tRNAs) from 85 species (20 families in eight superfamilies). The general genomic features found in the butterflies also were found in the five skippers: a high A+T composition (79.3%-80.9%), dominant usage of TAA stop codon, similar skewness pattern in both strands, consistently length intergenic spacer sequence between tRNA(Gln) and ND2 (64-87 bp), conserved ATACTAA motif between tRNA(Ser (UCN)) and ND1, and characteristic features of the A+T-rich region (the ATAGA motif, varying length of poly-T stretch, and poly-A stretch). The start codon for COI was CGA in four skippers as typical, but Lobocla bifasciatus evidently possessed canonical ATG as start codon. All species had the ancestral arrangement tRNA(Asn)/tRNA(Ser (AGN)), instead of the rearrangement tRNA(Ser (AGN))/tRNA(Asn), found in another skipper species (Erynnis). Phylogenetic analyses using all available genes (PCGs, rRNAS, and tRNAs) yielded the consensus superfamilial relationships ((((((Bombycoidea+Noctuoidea+Geometroidea)+Pyraloidea)+Papilionoidea)+Tortricoidea)+Yponomeutoidea)+Hepialoidea), confirming the validity of Macroheterocera (Bombycoidea, Noctuoidea, and Geometroidea in this study) and its sister relationship to Pyraloidea. Within Rhopalocera (butterflies and skippers) the familial relationships (Papilionidae+(Hesperiidae+(Pieridae+((Lycaenidae+Riodinidae)+Nymphalidae)))) were strongly supported in all analyses (0.98-1 by BI and 96-100 by ML methods), rendering invalid the superfamily status for Hesperioidea. On the other hand, current mitogenome-based phylogeny did not find consistent superfamilial relationships among Noctuoidea, Geometroidea, and Bombycoidea and the familial relationships within Bombycoidea between analyses, requiring further taxon sampling in future studies.