Chromosome-level genome assembly of the snakefly Mongoloraphidia duomilia (Raphidioptera: Raphidiidae).

Raphidioptera (snakeflies) are a holometabolan order with the least species diversity but play a pivotal role in understanding the origin of complete metamorphosis. Here, we provide an annotated, chromosome-level reference genome assembly for an Asian endemic snakefly Mongoloraphidia duomilia (Yang, 1998) of the family Raphidiidae, assembled using PacBio HiFi and Hi-C data from female specimens. The resulting assembly is 653.56 Mb, of which 97.90% is anchored into 13 chromosomes. The scaffold N50 is 53.50 Mb, and BUSCO completeness is 97.80%. Repetitive elements comprise 64.31% of the genome (366.04 Mb). We identified 599 noncoding RNAs and predicted 11,141 protein-coding genes in the genome (97.70% BUSCO completeness). The new snakefly genome will facilitate comparison of genome architecture across Neuropterida and Holometabola and shed light on the ecological and evolutionary transitions between Neuropterida and Coleopterida.

Comparative analyses of the banded alder borer (Rosalia funebris) and Asian longhorned beetle (Anoplophora glabripennis) genomes reveal significant differences in genome architecture and gene content among these and other Cerambycidae.

Rosalia funebris (RFUNE; Cerambycidae), the banded alder borer, is a longhorn beetle whose larvae feed on the wood of various economically and ecologically significant trees in western North America. Adults are short-lived and not known to consume plant material substantially. We sequenced, assembled and annotated the RFUNE genome using HiFi and RNASeq data. We documented genome architecture and gene content, focusing on genes putatively involved in plant feeding (phytophagy). Comparisons were made to the well-studied genome of the Asian longhorned beetle (AGLAB; Anoplophora glabripennis) and other Cerambycidae. The 814 Mb RFUNE genome assembly was distributed across 42 contigs, with an N50 of 30.18 Mb. Repetitive sequences comprised 60.27 % of the genome, and 99.0 % of expected single-copy orthologous genes were fully assembled. We identified 12657 genes, fewer than in the four other species studied, and 46.4 % fewer than for Aromia moschata (same subfamily as RFUNE). Of the 7258 orthogroups shared between RFUNE and AGLAB, 1461 had more copies in AGLAB and 1023 had more copies in RFUNE. We identified 240 genes in RFUNE that putatively arose via horizontal transfer events. The RFUNE genome encoded substantially fewer putative plant cell wall degrading enzymes than AGLAB, which may relate to the longer-lived plant-feeding adults of the latter species. The RFUNE genome provides new insights into cerambycid genome architecture and gene content and provides a new vantage point from which to study the evolution and genomic basis of phytophagy in beetles.

The genome of the invasive and broadly polyphagous Diaprepes root weevil, Diaprepes abbreviatus (Coleoptera), reveals an arsenal of putative polysaccharide-degrading enzymes.

The Diaprepes root weevil (DRW), Diaprepes abbreviatus, is a broadly polyphagous invasive pest of agriculture in the southern United States and the Caribbean. Its genome was sequenced, assembled, and annotated to study genomic correlates of specialized plant-feeding and invasiveness and to facilitate the development of new methods for DRW control. The 1.69 Gb D. abbreviatus genome assembly was distributed across 653 contigs, with an N50 of 7.8 Mb and the largest contig of 62 Mb. Most of the genome was comprised of repetitive sequences, with 66.17% in transposable elements, 5.75% in macrosatellites, and 2.06% in microsatellites. Most expected orthologous genes were present and fully assembled, with 99.5% of BUSCO genes present and 1.5% duplicated. One hundred and nine contigs (27.19 Mb) were identified as putative fragments of the X and Y sex chromosomes, and homology assessment with other beetle X chromosomes indicated a possible sex chromosome turnover event. Genome annotation identified 18,412 genes, including 43 putative horizontally transferred (HT) loci. Notably, 258 genes were identified from gene families known to encode plant cell wall degrading enzymes and invertases, including carbohydrate esterases, polysaccharide lyases, and glycoside hydrolases (GH). GH genes were unusually numerous, with 239 putative genes representing 19 GH families. Interestingly, several other beetle species with large numbers of GH genes are (like D. abbreviatus) successful invasive pests of agriculture or forestry.

Phylogenomics resolves timing and patterns in the evolution of Australasian Cerambycinae (Coleoptera: Cerambycidae), and reveals new insights into the subfamily-level classification and historical biogeography of longhorn beetles.

Cerambycinae is the second-largest subfamily of longhorn beetles in the Southern Hemisphere. The phylogeny of Cerambycinae is poorly known, resulting in a highly artificial tribal-level classification and a largely speculative evolutionary history. We reconstructed the phylogenetic relationships of Cerambycinae at the generic level using anchored hybrid enrichment data from hundreds of nuclear genes, with a primary focus on the extraordinarily diverse faunas of Australia and New Zealand. We also estimated divergence times by incorporating fossil calibrations in our analyses. We identified two main clades within Cerambycinae, which can also be separated morphologically by a distinct type of antennal foramen. We recovered a Late Jurassic origin of crown Cerambycinae. Dorcasominae, which was newly found to have representatives in Australia, was notably derived from within Cerambycinae. We recovered two independent origins of Australian Cerambycinae: one clade originated in the Early Cretaceous and is likely endemic to the Southern Hemisphere, while the other clade appears to have immigrated to Australia, perhaps from the Northern Hemisphere. Within the Australian lineages were multiple independent origins of New Zealand taxa, all of which are relative host-plant generalists. Tribal relationships and assignments are discussed, and based on our results, the following major nomenclatural acts were made: Dorcasominae Lacordaire, 1868 is downgraded to a tribe Dorcasomini of Cerambycinae Latreille, 1804; Neostenini Lacordaire, 1868 syn. nov. is treated as a junior synonym of Uracanthini Blanchard, 1851.

Metagenomic clustering reveals microbial contamination as an essential consideration in ultraconserved element design for phylogenomics with insect museum specimens.

Phylogenomics via ultraconserved elements (UCEs) has led to improved phylogenetic reconstructions across the tree of life. However, inadvertently incorporating non-targeted DNA into the UCE marker design will lead to misinformation being incorporated into subsequent analyses. To date, the effectiveness of basic metagenomic filtering strategies has not been assessed in arthropods. Designing markers from museum specimens requires careful consideration of methods due to the high levels of microbial contamination typically found in such specimens. We investigate if contaminant sequences are carried forward into a UCE marker set we developed from insect museum specimens using a standard bioinformatics pipeline. We find that the methods currently employed by most researchers do not exclude contamination from the final set of targets. Lastly, we highlight several paths forward for reducing contamination in UCE marker design.

Fifty million years of beetle evolution along the Antarctic Polar Front.

Global cooling and glacial-interglacial cycles since Antarctica's isolation have been responsible for the diversification of the region's marine fauna. By contrast, these same Earth system processes are thought to have played little role terrestrially, other than driving widespread extinctions. Here, we show that on islands along the Antarctic Polar Front, paleoclimatic processes have been key to diversification of one of the world's most geographically isolated and unique groups of herbivorous beetles-Ectemnorhinini weevils. Combining phylogenomic, phylogenetic, and phylogeographic approaches, we demonstrate that these weevils colonized the sub-Antarctic islands from Africa at least 50 Ma ago and repeatedly dispersed among them. As the climate cooled from the mid-Miocene, diversification of the beetles accelerated, resulting in two species-rich clades. One of these clades specialized to feed on cryptogams, typical of the polar habitats that came to prevail under Miocene conditions yet remarkable as a food source for any beetle. This clade's most unusual representative is a marine weevil currently undergoing further speciation. The other clade retained the more common weevil habit of feeding on angiosperms, which likely survived glaciation in isolated refugia. Diversification of Ectemnorhinini weevils occurred in synchrony with many other Antarctic radiations, including penguins and notothenioid fishes, and coincided with major environmental changes. Our results thus indicate that geo-climatically driven diversification has progressed similarly for Antarctic marine and terrestrial organisms since the Miocene, potentially constituting a general biodiversity paradigm that should be sought broadly for the region's taxa.

Generic relationships of New World Jerusalem crickets (Orthoptera: Stenopelmatoidea:Stenopelmatinae), including all known species of Stenopelmatus.

The New World Jerusalem crickets currently consist of 4 genera: Stenopelmatus Burmeister, 1838, with 33 named entities; Ammopelmatus Tinkham, 1965, with 2 described species; Viscainopelmatus Tinkham, 1970, with 1 described species, and Stenopelmatopterus Gorochov, 1988, with 3 described species. We redefine the generic boundaries of these 4 genera, synonymize Stenopelmatopterus under Stenopelmatus, and synonymize Viscainopelmatus under Ammopelmatus. We then discuss, and illustrate, all the types of the species of Stenopelmatus, all of which only occur south of the United States' border.                We recognize as valid the following 5 described Mexican and Central American species: S. ater, S. piceiventris, S. sartorianus, S. talpa, and S. typhlops. We declare the following 13 described Mexican and Central American Stenopelmatus taxa as nomen dubium: S. calcaratus, S. erythromelus, S. guatemalae, S. histrio, S. lessonae, S. lycosoides, S. mexicanus, S. minor, S. nieti, S. sallei, S. sumichrasti, S. toltecus, and S. vicinus. We designate a neotype for S. talpa and lectotypes for S. ater, S. guatemalae, S. histrio, S. lessonae, S. mexicanus, S. minor, S. nieti, S. sallei, S. sumichrasti, and S. toltecus. We assign a type locality for S. piceiventris. We concur with the previous synonymy of S. politus under S. sartorianus. We describe 14 new species of Stenopelmatus from Mexico, Honduras and Ecuador, based on a combination of adult morphology, DNA, calling song drumming pattern, distribution, and karyotype: S. chiapas sp. nov., S. cusuco sp. nov., S. diezmilpies sp. nov., S. durango sp. nov., S. ecuadorensis sp. nov., S. faulkneri sp. nov., S. honduras sp. nov., S. hondurasito sp. nov., S. mineraldelmonte sp. nov., S. nuevoleon sp. nov., S. perote sp. nov., S. saltillo sp. nov., S. sanfelipe sp. nov., and S. zimapan sp. nov.                  We transfer the following 16 described United States taxa, plus S. cephalotes from the "west coast of North America", from Stenopelmatus to Ammopelmatus: A. cahuilaensis, A. californicus, A. cephalotes, A. fasciatus, A. fuscus, A. hydrocephalus, A. intermedius, A. irregularis, A. longispinus, A. mescaleroensis, A. monahansensis, A. navajo, A. nigrocapitatus, A. oculatus, A. pictus, and A. terrenus, along with the Mexican taxon A. comanchus: these species will be discussed in a subsequent paper (Weissman et al. in prep).                We believe that all new Jerusalem cricket species descriptions should include, at a minimum, calling drum (most important) and DNA information.

Author Correction: Phylogenomic analysis sheds light on the evolutionary pathways towards acoustic communication in Orthoptera.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Phylogenomic analysis sheds light on the evolutionary pathways towards acoustic communication in Orthoptera.

Acoustic communication is enabled by the evolution of specialised hearing and sound producing organs. In this study, we performed a large-scale macroevolutionary study to understand how both hearing and sound production evolved and affected diversification in the insect order Orthoptera, which includes many familiar singing insects, such as crickets, katydids, and grasshoppers. Using phylogenomic data, we firmly establish phylogenetic relationships among the major lineages and divergence time estimates within Orthoptera, as well as the lineage-specific and dynamic patterns of evolution for hearing and sound producing organs. In the suborder Ensifera, we infer that forewing-based stridulation and tibial tympanal ears co-evolved, but in the suborder Caelifera, abdominal tympanal ears first evolved in a non-sexual context, and later co-opted for sexual signalling when sound producing organs evolved. However, we find little evidence that the evolution of hearing and sound producing organs increased diversification rates in those lineages with known acoustic communication.

Gene content evolution in the arthropods.

BACKGROUND: Arthropods comprise the largest and most diverse phylum on Earth and play vital roles in nearly every ecosystem. Their diversity stems in part from variations on a conserved body plan, resulting from and recorded in adaptive changes in the genome. Dissection of the genomic record of sequence change enables broad questions regarding genome evolution to be addressed, even across hyper-diverse taxa within arthropods. RESULTS: Using 76 whole genome sequences representing 21 orders spanning more than 500 million years of arthropod evolution, we document changes in gene and protein domain content and provide temporal and phylogenetic context for interpreting these innovations. We identify many novel gene families that arose early in the evolution of arthropods and during the diversification of insects into modern orders. We reveal unexpected variation in patterns of DNA methylation across arthropods and examples of gene family and protein domain evolution coincident with the appearance of notable phenotypic and physiological adaptations such as flight, metamorphosis, sociality, and chemoperception. CONCLUSIONS: These analyses demonstrate how large-scale comparative genomics can provide broad new insights into the genotype to phenotype map and generate testable hypotheses about the evolution of animal diversity.

The evolution and genomic basis of beetle diversity.

The order Coleoptera (beetles) is arguably the most speciose group of animals, but the evolutionary history of beetles, including the impacts of plant feeding (herbivory) on beetle diversification, remain poorly understood. We inferred the phylogeny of beetles using 4,818 genes for 146 species, estimated timing and rates of beetle diversification using 89 genes for 521 species representing all major lineages and traced the evolution of beetle genes enabling symbiont-independent digestion of lignocellulose using 154 genomes or transcriptomes. Phylogenomic analyses of these uniquely comprehensive datasets resolved previously controversial beetle relationships, dated the origin of Coleoptera to the Carboniferous, and supported the codiversification of beetles and angiosperms. Moreover, plant cell wall-degrading enzymes (PCWDEs) obtained from bacteria and fungi via horizontal gene transfers may have been key to the Mesozoic diversification of herbivorous beetles-remarkably, both major independent origins of specialized herbivory in beetles coincide with the first appearances of an arsenal of PCWDEs encoded in their genomes. Furthermore, corresponding (Jurassic) diversification rate increases suggest that these novel genes triggered adaptive radiations that resulted in nearly half of all living beetle species. We propose that PCWDEs enabled efficient digestion of plant tissues, including lignocellulose in cell walls, facilitating the evolution of uniquely specialized plant-feeding habits, such as leaf mining and stem and wood boring. Beetle diversity thus appears to have resulted from multiple factors, including low extinction rates over a long evolutionary history, codiversification with angiosperms, and adaptive radiations of specialized herbivorous beetles following convergent horizontal transfers of microbial genes encoding PCWDEs.

Patterns and Constraints in the Evolution of Sperm Individualization Genes in Insects, with an Emphasis on Beetles.

Gene expression profiles can change dramatically between sexes and sex bias may contribute specific macroevolutionary dynamics for sex-biased genes. However, these dynamics are poorly understood at large evolutionary scales due to the paucity of studies that have assessed orthology and functional homology for sex-biased genes and the pleiotropic effects possibly constraining their evolutionary potential. Here, we explore the correlation of sex-biased expression with macroevolutionary processes that are associated with sex-biased genes, including duplications and accelerated evolutionary rates. Specifically, we examined these traits in a group of 44 genes that orchestrate sperm individualization during spermatogenesis, with both unbiased and sex-biased expression. We studied these genes in the broad evolutionary framework of the Insecta, with a particular focus on beetles (order Coleoptera). We studied data mined from 119 insect genomes, including 6 beetle models, and from 19 additional beetle transcriptomes. For the subset of physically and/or genetically interacting proteins, we also analyzed how their network structure may condition the mode of gene evolution. The collection of genes was highly heterogeneous in duplication status, evolutionary rates, and rate stability, but there was statistical evidence for sex bias correlated with faster evolutionary rates, consistent with theoretical predictions. Faster rates were also correlated with clocklike (insect amino acids) and non-clocklike (beetle nucleotides) substitution patterns in these genes. Statistical associations (higher rates for central nodes) or lack thereof (centrality of duplicated genes) were in contrast to some current evolutionary hypotheses, highlighting the need for more research on these topics.

Tonantzin, a New Genus of Bess Beetle (Coleoptera, Passalidae) from a Montane Subtropical Forest in Central Mexico, with a Review of the Taxonomic Significance of the Mesofrontal Structure in Proculini.

Mexico has the third highest diversity of passalid beetles in the World. Here we describe Tonantzin new genus, a new monotypic genus, potentially endemic to the mountains of central Mexico. The new genus is diagnosed by a new configuration of characters from the mesofrontal structure (MFS) in addition to other characters. The MFS in Passalidae has been treated either as a composite complex character or a combination of individual characters. Using a broad taxonomic sample within Proculini, we discuss the taxonomic and systematic implications of the MFS for the tribe. We define the MFS type tepetl. Given the importance of the MFS for passalid taxonomy we propose a new delimitation of the structure using boundaries based on internal and external head structures. We argue that the treatment of the MFS as a complex character better captures the nature of this structure but we ultimately find a need to standardize the way in which this structure is described in the taxonomic literature and used in phylogenetic analyses.

Genomic signatures accompanying the dietary shift to phytophagy in polyphagan beetles.

BACKGROUND: The diversity and evolutionary success of beetles (Coleoptera) are proposed to be related to the diversity of plants on which they feed. Indeed, the largest beetle suborder, Polyphaga, mostly includes plant eaters among its approximately 315,000 species. In particular, plants defend themselves with a diversity of specialized toxic chemicals. These may impose selective pressures that drive genomic diversification and speciation in phytophagous beetles. However, evidence of changes in beetle gene repertoires driven by such interactions remains largely anecdotal and without explicit hypothesis testing. RESULTS: We explore the genomic consequences of beetle-plant trophic interactions by performing comparative gene family analyses across 18 species representative of the two most species-rich beetle suborders. We contrast the gene contents of species from the mostly plant-eating suborder Polyphaga with those of the mainly predatory Adephaga. We find gene repertoire evolution to be more dynamic, with significantly more adaptive lineage-specific expansions, in the more speciose Polyphaga. Testing the specific hypothesis of adaptation to plant feeding, we identify families of enzymes putatively involved in beetle-plant interactions that underwent adaptive expansions in Polyphaga. There is notable support for the selection hypothesis on large gene families for glutathione S-transferase and carboxylesterase detoxification enzymes. CONCLUSIONS: Our explicit modeling of the evolution of gene repertoires across 18 species identifies putative adaptive lineage-specific gene family expansions that accompany the dietary shift towards plants in beetles. These genomic signatures support the popular hypothesis of a key role for interactions with plant chemical defenses, and for plant feeding in general, in driving beetle diversification.

Species characteristics affect local extinctions.

PREMISE OF THE STUDY: Human activities threaten thousands of species with extinction. However, it remains difficult to predict extinction risk for many vulnerable species. Species traits, species characteristics such as rarity or habitat use, and phylogenetic patterns are associated with responses to anthropogenic environmental change and may help predict likelihood of extinction. METHODS: We used historical botanical data from Kalamazoo County, Michigan, USA, to examine whether species traits (growth form, life history, nitrogen-fixation, photosynthetic pathway), species characteristics (community association, species origin, range edge, habitat specialization, rarity), or phylogenetic relatedness explain local species loss at the county level. KEY RESULTS: Across Kalamazoo County, prairie species, species at the edge of their native range, regionally rare species, and habitat specialists were most likely to become locally extinct. Prairie species experienced the highest local extinction rates of any habitat type, and among prairie species, regionally rare and specialist species were most vulnerable to loss. We found no evidence for a phylogenetic pattern in plant extinctions. CONCLUSIONS: Our study illustrates the value of historical datasets for understanding and potentially predicting biodiversity loss. Not surprisingly, rare, specialist species occupying threatened habitats are most at risk of local extinction. As a result, identifying mechanisms to conserve or restore rare or declining species and preventing further habitat destruction may be the most effective strategies for reducing future extinction.

Climate and host-plant associations shaped the evolution of ceutorhynch weevils throughout the Cenozoic.

Using molecular phylogenetic data and methods we inferred divergence times and diversification patterns for the weevil subfamily Ceutorhynchinae in the context of host-plant associations and global climate over evolutionary time. We detected four major diversification shifts that correlate with both host shifts and major climate events. Ceutorhynchinae experienced an increase in diversification rate at ∼53 Ma, during the Early Eocene Climate Optimum, coincident with a host shift to Lamiaceae. A second major diversification phase occurred at the end of the Eocene (∼34 Ma). This contrasts with the overall deterioration in climate equability at the Eocene-Oligocene boundary, but tracks the diversification of important host plant clades in temperate (higher) latitudes, leading to increased diversification rates in the weevil clades infesting temperate hosts. A third major phase of diversification is correlated with the rising temperatures of the Late Oligocene Warming Event (∼26.5 Ma); diversification rates then declined shortly after the Middle Miocene Climate Transition (∼14.9 Ma). Our results indicate that biotic and abiotic factors together explain the evolution of Ceutorhynchinae better than each of these drivers viewed in isolation.

Phylogenomics clarifies repeated evolutionary origins of inbreeding and fungus farming in bark beetles (Curculionidae, Scolytinae).

Bark and ambrosia beetles (Curculionidae, Scolytinae) display a conspicuous diversity of unusual genetic and ecological attributes and behaviors. Reconstructing the evolution of Scolytinae, particularly the large and ecologically significant tribe Cryphalini (pygmy borers), has long been problematic. These challenges have not adequately been addressed using morphological characters, and previous research has used only DNA sequence data from small numbers of genes. Through a combination of anchored hybrid enrichment, low-coverage draft genomes, and transcriptomes, we addressed these challenges by amassing a large molecular phylogenetic dataset for bark and ambrosia beetles. The resulting DNA sequence data from 251 protein coding genes (114,276 bp of nucleotide sequence data) support inference of the first robust phylogeny of Scolytinae, with a special focus on the species rich tribe Cryphalini and its close relatives. Key strategies, including inbreeding mating systems and fungus farming, evolved repeatedly across Scolytinae. We confirm 12 of 16 hypothesized origins of fungus farming, 6 of 8 origins of inbreeding polygyny and at least 11 independent origins of a super-generalist host range. These three innovations are statistically correlated, but their appearance within lineages was not necessarily simultaneous. Additionally, the evolution of extreme host plant generalism often preceded, rather than succeeded, fungus farming. Of the high-diversity tribes of Scolytinae, only Xyleborini is monophyletic, Corthylini is paraphyletic and Cryphalini is highly polyphyletic. Cryphalini sensu stricto is part of a clade containing the genera Hypothenemus, Cryphalus and Trypophloeus, and the tribe Xyloterini. Stegomerus and Cryptocarenus (Cryphalini) are part of a clade otherwise containing all Corthylini. Several other genera, including Ernoporus and Scolytogenes (Cryphalini), make up a distantly related clade. Several of the genera of Cryphalini are also intermixed. For example, Cryphalus and Hypocryphalus are intermingled, as well as Ernoporicus, Ptilopodius and Scolytogenes. Our data are consistent with widespread polyphyly and paraphyly across Scolytinae and within Cryphalini, and provides new insights into the evolution of inbreeding mating systems and fungus farming in the species rich and ecologically significant weevil subfamily Scolytinae.

Beetle genomes in the 21st century: prospects, progress and priorities.

The order Coleoptera (beetles) is arguably the most species-rich lineage of animals. Beetles exhibit an extraordinary variety of life histories and occupy most terrestrial environments. Whole genome sequences are available for 11 beetle species, only six of which have been published. Studies of beetle genomes have revealed remarkable new insights into the genomic basis and evolution of beetle life histories and other aspects of beetle biodiversity, including the genes underlying chemoperception, detoxification, and specialized plant feeding, as well as the role of horizontal gene transfer in elaboration of the beetle trophic repertoire. Nonetheless, such studies are in their infancy. The study of beetle genomes has the potential to further revolutionize our understanding of beetle biodiversity, but genomic studies of beetles remain seriously limited in scope and resolution by the very few genomes that are currently available for study.

Phylogenomic Data Yield New and Robust Insights into the Phylogeny and Evolution of Weevils.

The phylogeny and evolution of weevils (the beetle superfamily Curculionoidea) has been extensively studied, but many relationships, especially in the large family Curculionidae (true weevils; > 50,000 species), remain uncertain. We used phylogenomic methods to obtain DNA sequences from 522 protein-coding genes for representatives of all families of weevils and all subfamilies of Curculionidae. Most of our phylogenomic results had strong statistical support, and the inferred relationships were generally congruent with those reported in previous studies, but with some interesting exceptions. Notably, the backbone relationships of the weevil phylogeny were consistently strongly supported, and the former Nemonychidae (pine flower snout beetles) were polyphyletic, with the subfamily Cimberidinae (here elevated to Cimberididae) placed as sister group of all other weevils. The clade comprising the sister families Brentidae (straight-snouted weevils) and Curculionidae was maximally supported and the composition of both families was firmly established. The contributions of substitution modeling, codon usage and/or mutational bias to differences between trees reconstructed from amino acid and nucleotide sequences were explored. A reconstructed timetree for weevils is consistent with a Mesozoic radiation of gymnosperm-associated taxa to form most extant families and diversification of Curculionidae alongside flowering plants-first monocots, then other groups-beginning in the Cretaceous.

Overcoming the loss of blue sensitivity through opsin duplication in the largest animal group, beetles.

Opsin proteins are fundamental components of animal vision whose structure largely determines the sensitivity of visual pigments to different wavelengths of light. Surprisingly little is known about opsin evolution in beetles, even though they are the most species rich animal group on Earth and exhibit considerable variation in visual system sensitivities. We reveal the patterns of opsin evolution across 62 beetle species and relatives. Our results show that the major insect opsin class (SW) that typically confers sensitivity to "blue" wavelengths was lost ~300 million years ago, before the origin of modern beetles. We propose that UV and LW opsin gene duplications have restored the potential for trichromacy (three separate channels for colour vision) in beetles up to 12 times and more specifically, duplications within the UV opsin class have likely led to the restoration of "blue" sensitivity up to 10 times. This finding reveals unexpected plasticity within the insect visual system and highlights its remarkable ability to evolve and adapt to the available light and visual cues present in the environment.