The order Psocodea includes the two historically recognized groups Psocoptera (free-living bark lice) and Phthiraptera (parasitic lice) that were once considered separate orders. Psocodea is divided in three suborders: Trogiomorpha, Troctomorpha, and Psocomorpha, the latter being the largest within the free-living groups. Despite the increasing number of transcriptomes and whole genome sequence (WGS) data available for this group, the relationships among the six known infraorders within Psocomorpha remain unclear. Here, we evaluated the utility of a bait set designed specifically for parasitic lice belonging to suborder Troctomorpha to extract UCE loci from transcriptome and WGS data of 55 bark louse species and explored the phylogenetic relationships within Psocomorpha using these UCE loci markers. Taxon sampling was heavily focused on the families Lachesillidae and Elipsocidae, whose relationships have been problematic in prior phylogenetic studies. We successfully recovered a total of 2,622 UCE loci, with a 40% completeness matrix containing 2,081 UCE loci and an 80% completeness matrix containing 178 UCE loci. The average number of UCE loci recovered for the 55 species was 1,401. The WGS data sets produced a larger number of UCE loci (1,495) on average than the transcriptome data sets (972). Phylogenetic relationships reconstructed with Maximum Likelihood and coalescent-based analysis were concordant regarding the paraphyly of Lachesillidae and Elipsocidae. Branch support values were generally lower in analyses that used a fewer number of loci, even though they had higher matrix completeness.

El orden Psocodea incluye actualmente a dos grupos históricamente reconocidos y que una vez fueron considerados órdenes separados, Psocoptera (piojos de vida libre o de las cortezas) y Phthiraptera (piojos verdaderos). Psocodea está dividido en tres subórdenes: Trogiomorpha, Troctomorpha y Psocomorpha, este último siendo el más grande entre los piojos de vida libre. A pesar de que la cantidad de información disponible sobre transcriptomas y secuenciación del genoma completo (WGS) para este grupo se ha incrementado notablemente en los últimos años, las relaciones filogenéticas dentro de Psocomorpha permanecen poco claras. En este estudio, evaluamos la utilidad de un conjunto de sondas diseñadas específicamente a partir de especies de piojos verdaderos del suborden Troctormorpha, para capturar elementos ultra-conservados (UCE) a partir de las secuencias de transcriptomas y WGS de 55 especies de piojos de las cortezas. Igualmente, exploramos las relaciones filogenéticas dentro de Psocomorpha usando estos marcadores de UCE. El muestreo taxonómico estuvo fuertemente enfocado en las familias Lachesillidae y Elipsocidae, ya que sus relaciones han demostrado ser problemáticas en estudios filogenéticos previos. Como resultado, logramos recuperar exitosamente un total de 2,622 marcadores de UCE, con las matrices de completitud del 40% y 80% conteniendo 2,081 y 178 marcadores de UCE respectivamente. El número promedio de UCE recuperados para las 55 especies fue de 1,401. En promedio, el conjunto de datos de WGS produjo un mayor número de loci de UCE (1,495) que las secuencias de transcriptomas (972). Las relaciones filogenéticas reconstruidas a partir de análisis de máxima verosimilitud y métodos coalescentes fueron concordantes respecto a la parafília de Lachesillidae y Elipsocidae, mientras que los valores de soporte de ramas fueron generalmente más bajos en los análisis que incluyeron menor número de loci aún cuando la matriz de completitud era más grande.

Graphical Abstract

Pseudocryptic species, those that are difficult to diagnose using traditional taxonomic methods, are serious impediments for recognizing the introduction of non-native species. Rapid identification of species facilitates a rapid response to newly introduced species which can lessen their damaging effects. This situation is acute for known pest species such as xyleborine ambrosia beetles which are difficult to identify given minute morphological, often variable, diagnostic characters. These beetles have been introduced into non-native temperate regions and have caused economic and ecological havoc. In this study, we produced DNA-based phylogenies using four genes for individuals of Cyclorhipidion bodoanum (Reitter, 1913), C. distinguendum (Eggers, 1930), and C. pelliculosum (Eichhoff, 1878) sampled from their introduced and native Asian ranges and as well as other Cyclorhipidion species. In addition, we review subtle morphological characters for diagnostic potential for these similar species. Bayesian phylogenetic analysis produced well-resolved and supported phylogeny that provided evidence for multiple introductions of C. bodoanum and C. distinguendum into the United States and the occurrence of pseudocryptic species. The ambrosia beetles Cyclorhipidion tenuigraphum (Schedl, 1953) and C. nemesis Smith & Cognato, sp. nov. are reported in North America for the first time. We find that the pattern of elytral interstrial setae is an unrealized source for the identification of Cyclorhipidion species. This study resulted in the recognition of six species adventive to the United States with the revised status of C. californicum (Wood, 1975). All species known from North American are diagnosed, illustrated and a key is provided.

Plant-associated arthropods have been shown to cross large oceanic distances on floating plant material and to establish themselves on distant landmasses. Xyleborini (Coleoptera: Curculionidae: Scolytinae) ambrosia beetles occur in forests worldwide and are likely capable of long range dispersal. In less than 20 million years, this group dispersed from Asia to tropical regions of Africa and South America. The phylogeny, taxonomy, and biogeography of one Xyleborus species group which occurs on both continents are reviewed for this study. Based on a well-resolved molecular phylogeny resulting from parsimony, likelihood, and Bayesian analyses of four gene loci, we describe a new monophyletic genus, Xenoxylebora Osborn, Smith & Cognato, gen. nov., for this bicontinental Xyleborus species group with seven Afrotropical and six Neotropical species. Six new species are described: Xenoxylebora pilosa Osborn, Smith & Cognato, sp. nov. from Africa, and Xenoxylebora addenda Osborn, Smith & Cognato, sp. nov., Xenoxylebora calculosa Osborn, Smith & Cognato, sp. nov., Xenoxylebora hystricosa Osborn, Smith & Cognato, sp. nov., Xenoxylebora serrata Osborn, Smith & Cognato, sp. nov., and Xenoxylebora sulcata Osborn, Smith & Cognato, sp. nov., from South America. Seven new combinations from Xyleborus are proposed: Xenoxylebora caudata (Schedl 1957) comb. nov., Xenoxylebora collarti (Eggers 1932) comb. nov., Xenoxylebora perdiligens (Schedl 1937) comb. nov., Xenoxylebora sphenos (Sampson 1912) comb. nov., Xenoxylebora subcrenulata (Eggers 1932) comb. nov., and Xenoxylebora syzygii (Nunberg 1959) comb. nov. from Africa, and Xenoxylebora neosphenos (Schedl 1976) comb. nov. from South America. One new synonym is proposed: Xenoxylebora sphenos (Sampson 1912) = Xyleborus tenellus Schedl 1957 syn. nov. Descriptions, diagnoses, images, and a key to the identification of all 13 species are provided. The sequence of colonization between Africa and South America is uncertain for Xenoxylebora. Prevailing ocean currents and predominant locality patterns observed for other organisms suggest an African Xenoxylebora origin. However, the phylogeny, biogeographical analyses, and a calibrated divergence time suggest a possible South American origin for African Xenoxylebora (2.3 Ma, 95% HDP 4.5–0.6 Ma), which is supported by the occurrence of ocean counter currents between the continents and evidence of dispersal from South America to Africa among some plant and arthropod taxa.

Deciphering the timing of lineage diversification and extinction has greatly benefited in the last decade from methodological developments in fossil-based analyses. If these advances are increasingly used to study the past dynamics of vertebrates, other taxa such as insects remain relatively neglected. Our understanding of how insect clades waxed and waned or of the impact of major paleoenvironmental changes during their periods of diversification and extinction (mass extinction) are rarely investigated. Here, we compile and analyze the fossil record of Plecoptera (1,742 vetted occurrences) to investigate their genus-level diversification and diversity dynamics using a Bayesian process-based model that incorporates temporal preservation biases. We found that the Permian-Triassic mass extinction has drastically impacted Plecoptera, while the Cretaceous Terrestrial Revolution corresponds with a turnover of plecopteran fauna. We also unveiled three major gaps in the plecopteran fossil record: the Carboniferous-Permian transition, the late Early Cretaceous, and the late Cenomanian to Bartonian, which will need to be further investigated. Based on the life history of extant Plecoptera, we investigate the correlations between their past dynamic and a series of biotic (Red Queen hypothesis) and abiotic (Court Jester hypothesis) factors. These analyses highlight the major role of continental fragmentation in the evolutionary history of stoneflies, which is in line with phylogeny-based biogeographic analyses showing how vicariance drove their diversification. Our study advocates analyzing the fossil record with caution, while attempting to unveil the diversification and extinction periods plus the likely triggers of these past dynamics of diversification.

In millipedes, gonopods are male copulatory genitalia derived from walking legs that metamorphose during postembryonic development. The morphology of gonopods is critical for genus and species diagnosis in most taxa. However, the form and function of gonopods vary drastically at the family and ordinal level, making intricate morphological comparison practically impossible. Internal morphology could provide the basis for homologizing morphological elements present in the walking legs and gonopods. Therefore, we used x-ray computed tomography to produce 3D segmentations of Pseudopolydesmus Attems, 1898 (Polydesmida: Polydesmidae) millipedes incorporating two types of morphological elements: skeletal elements and muscles. In addition to imaging the trunk and appendages of an adult male, we imaged the developing gonopod across a series of juvenile male stadia in order to trace the identities of morphological elements. Skeletal elements were homologized, but muscle homologies were limited by the dissimilarity of muscle attachment sites between the walking leg and gonopod. Furthermore, images of juvenile males showed that appendage musculature is totally obliterated once gonopod development begins in the fourth stadium. Due to these limitations, we believe it may be more tractable to homologize gonopod musculature of various millipede taxa to each other than to that of the walking legs. Because distinct genetic developmental networks responsible for walking leg and gonopod patterning have been evolving separately since the common ancestor of gonopod-bearing millipedes (a case of paramorphy), skeletomusculature among gonopods of unrelated millipede taxa is expected to be more similar than that of the gonopod and walking leg within a given millipede lineage.

The advent of community-science databases in conjunction with museum specimen locality information has exponentially increased the power and accuracy of ecological niche modeling (ENM). Increased occurrence data has provided colossal potential to understand the distributions of lesser known or endangered species, including arthropods. Although niche modeling of termites has been conducted in the context of invasive and pest species, few studies have been performed to understand the distribution of basal termite genera. Using specimen records from the American Museum of Natural History (AMNH) as well as locality databases, we generated ecological niche models for 12 basal termite species belonging to six genera and three families. We extracted environmental data from the Worldclim 19 bioclimatic dataset v2, along with SoilGrids datasets and generated models using MaxEnt. We chose Optimal models based on partial Receiving Operating characteristic (pROC) and omission rate criterion and determined variable importance using permutation analysis. We also calculated response curves to understand changes in suitability with changes in environmental variables. Optimal models for our 12 termite species ranged in complexity, but no discernible pattern was noted among genera, families, or geographic range. Permutation analysis revealed that habitat suitability is affected predominantly by seasonal or monthly temperature and precipitation variation. Our findings not only highlight the efficacy of largely community-science and museum-based datasets, but our models provide a baseline for predictions of future abundance of lesser-known arthropod species in the face of habitat destruction and climate change.

Graphical Abstract

Despite recent advances in phylogenomics, the early evolution of the largest bee family, Apidae, remains uncertain, hindering efforts to understand the history of Apidae and establish a robust comparative framework. Confirming the position of Anthophorinae—a diverse, globally distributed lineage of apid bees—has been particularly problematic, with the subfamily recovered in various conflicting positions, including as sister to all other Apidae or to the cleptoparasitic Nomadinae. We aimed to resolve relationships in Apidae and Anthophorinae by combining dense taxon sampling, with rigorous phylogenomic analysis of a dataset consisting of ultraconserved elements (UCEs) acquired from multiple sources, including low-coverage genomes. Across a diverse set of analyses, including both concatenation and species tree approaches, and numerous permutations designed to account for systematic biases, Anthophorinae was consistently recovered as the sister group to all remaining Apidae, with Nomadinae sister to (Apinae, [Xylocopinae, Eucerinae]). However, several alternative support metrics (concordance factors, quartet sampling, and gene genealogy interrogation) indicate that this result should be treated with caution. Within Anthophorinae, all genera were recovered as monophyletic, following synonymization of Varthemapistra with Habrophorula. Our results demonstrate the value of dense taxon sampling in bee phylogenomics research and how implementing diverse analytical strategies is important for fully evaluating results at difficult nodes.