BackgroundRelatively little is known about the genomic basis and evolution of wood-feeding in beetles. We undertook genome sequencing and annotation, gene expression assays, studies of plant cell wall degrading enzymes, and other functional and comparative studies of the Asian longhorned beetle, Anoplophora glabripennis, a globally significant invasive species capable of inflicting severe feeding damage on many important tree species. Complementary studies of genes encoding enzymes involved in digestion of woody plant tissues or detoxification of plant allelochemicals were undertaken with the genomes of 14 additional insects, including the newly sequenced emerald ash borer and bull-headed dung beetle.ResultsThe Asian longhorned beetle genome encodes a uniquely diverse arsenal of enzymes that can degrade the main polysaccharide networks in plant cell walls, detoxify plant allelochemicals, and otherwise facilitate feeding on woody plants. It has the metabolic plasticity needed to feed on diverse plant species, contributing to its highly invasive nature. Large expansions of chemosensory genes involved in the reception of pheromones and plant kairomones are consistent with the complexity of chemical cues it uses to find host plants and mates.ConclusionsAmplification and functional divergence of genes associated with specialized feeding on plants, including genes originally obtained via horizontal gene transfer from fungi and bacteria, contributed to the addition, expansion, and enhancement of the metabolic repertoire of the Asian longhorned beetle, certain other phytophagous beetles, and to a lesser degree, other phytophagous insects. Our results thus begin to establish a genomic basis for the evolutionary success of beetles on plants.Electronic supplementary materialThe online version of this article (doi:10.1186/s13059-016-1088-8) contains supplementary material, which is available to authorized users.

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.

Abstract. Cerambycidae is a species-rich family of mostly wood-feeding (xylophagous) beetles containing nearly 35 000 known species. The higher-level phylogeny of Cerambycidae has never been robustly reconstructed using molecular phylogenetic data or a comprehensive sample of higher taxa, and its internal relationships and evolutionary history remain the subjects of ongoing debate. We reconstructed the higher-level phylogeny of Cerambycidae using phylogenomic data from 522 single copy nuclear genes, generated via anchored hybrid enrichment. Our taxon sample (31 Chrysomeloidea, four outgroup taxa: two Curculionoidea and two Cucujoidea) included exemplars of all families and 23 of 30 subfamilies of Chrysomeloidea (18 of 19 non-chrysomelid Chrysomeloidea), with a focus on the large family Cerambycidae. Our results reveal a monophyletic Cerambycidae s.s. in all but one analysis, and a polyphyletic Cerambycidae s.l. When monophyletic, Cerambycidae s.s. was sister to the family Disteniidae. Relationships among the subfamilies of Cerambycidae s.s. were also recovered with strong statistical support except for Cerambycinae being made paraphyletic by Dorcasomus Audinet-Serville (Dorcasominae) in the nucleotide (but not amino acid) trees. Most other chrysomeloid families represented by more than one terminal taxon -Chrysomelidae, Disteniidae, Vesperidae and Orsodacnidae -were monophyletic, but Megalopodidae was rendered paraphyletic by Cheloderus Gray (Oxypeltidae). Our study corroborates some relationships within Chrysomeloidea that were previously inferred from morphological data, while also reporting several novel relationships. The present work thus provides a robust framework for future, more deeply taxon-sampled, phylogenetic and evolutionary studies of the families and subfamilies of Cerambycidae s.l. and other Chrysomeloidea.

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Taxonomic placement of the enigmatic monotypic Mexican longhorned beetle genus Vesperoctenus Bates is examined through inclusion in and reanalysis of the dataset of Haddad et al. (2018, Systematic Entomology 43: 68–89). We describe and discuss the phylogenetic significance of the internal structures of a recently collected V. flohri female from the Sierra de la Laguna mountain range in Mexico, the same specimen from which phylogenomic data was generated. Our phylogenomic analyses (469 genes) recovered Vesperoctenus with maximal statistical support within the cerambyciform family Vesperidae, sister to Vesperus Dejean (Vesperinae). Vesperus + Vesperoctenus were recovered sister to Philinae, and collectively form a clade sister to Anoplodermatinae. Thus, we place V. flohri within Vesperidae: Vesperinae: Vesperoctenini based on analyses of large-scale phylogenomic data. Finally, we propose that the conservation status of V. flohri merits assessment.