Geographic isolation drives speciation in Nearctic aphids.

Across herbivorous insect clades, species richness and host-use diversity tend to positively covary. This could be because host-use divergence drives speciation, or because it raises the ecological limits on species richness. To evaluate these hypotheses, we performed phylogenetic path model analyses of the species diversity of Nearctic aphids. Here, we show that variation in the species richness of aphid clades is caused mainly by host-use divergence, whereas variation in speciation rates is caused more by divergence in non-host-related niche variables. Aphid speciation is affected by both the evolution of host and non-host-related niche components, but the former is largely caused by the latter. Thus, our analyses suggest that host-use divergence can both raise the ecological limits on species richness and drive speciation, although in the latter case, host-use divergence tends to be a step along the causal path leading from non-host-related niche evolution to speciation.

Phylogenomics of braconid wasps (Hymenoptera, Braconidae) sheds light on classification and the evolution of parasitoid life history traits.

The parasitoid lifestyle is largely regarded as a key innovation that contributed to the evolutionary success and extreme species richness of the order Hymenoptera. Understanding the phylogenetic history of hyperdiverse parasitoid groups is a fundamental step in elucidating the evolution of biological traits linked to parasitoidism. We used a genomic-scale dataset based on ultra-conserved elements and the most comprehensive taxon sampling to date to estimate the evolutionary relationships of Braconidae, the second largest family of Hymenoptera. Based on our results, we propose Braconidae to comprise 41 extant subfamilies, confirmed a number of subfamilial placements and proposed subfamily-level taxonomic changes, notably the restoration of Trachypetinae stat. rev. and Masoninae stat. rev. as subfamilies of Braconidae, confirmation that Apozyx penyai Mason belongs in Braconidae placed in the subfamily Apozyginae and the recognition of Ichneutinae sensu stricto and Proteropinae as non-cyclostome subfamilies robustly supported in a phylogenetic context. The correlation between koinobiosis with endoparasitoidism and idiobiosis with ectoparasitoidism, long thought to be an important aspect in parasitoid life history, was formally tested and confirmed in a phylogenetic framework. Using ancestral reconstruction methods based on both parsimony and maximum likelihood, we suggest that the ancestor of the braconoid complex was a koinobiont endoparasitoid, as was that of the cyclostome sensu lato clade. Our results also provide strong evidence for one transition from endo- to ectoparasitoidism and three reversals back to endoparasitoidism within the cyclostome sensu stricto lineage. Transitions of koino- and idiobiosis were identical to those inferred for endo- versus ectoparasitoidism, except with one additional reversal back to koinobiosis in the small subfamily Rhysipolinae.

Molecular phylogeny, historical biogeography and revised classification of andrenine bees (Hymenoptera: Andrenidae).

The mining bee subfamily Andreninae (Hymenoptera: Andrenidae) is a widely distributed and diverse group of ground-nesting solitary bees, including numerous species known to be important pollinators. Most of the species diversity of Andreninae is concentrated in the mainly Holarctic genus Andrena, comprising ca. 1550 described species. The subfamily and especially the genus have remained relatively neglected by recent molecular phylogenetic studies, with current classifications relying largely on morphological characters. We sampled ultraconserved element (UCE) sequences from 235 taxa, including all andrenine genera and 98 out of 104 currently recognized Andrena subgenera. Using 419,858 aligned nucleotide sites from 1009 UCE loci, we present a comprehensive molecular phylogenetic analysis of the subfamily. Our analysis supports the recognition of seven distinct genera in the Andreninae: Alocandrena, Ancylandrena, Andrena, Cubiandrena, Euherbstia, Megandrena, and Orphana. Within the genus Andrena, present-day subgeneric concepts revealed high degrees of paraphyly and polyphyly, due to strong homoplasy of morphological characters, necessitating a thorough, extensive revision of the higher classification of the genus. Based on our findings, we place the subgenus Calcarandrena in synonymy with Andrena (Lepidandrena); Hyperandrena, Nemandrena, Scoliandrena, Tylandrena and Zonandrena with A. (Melandrena); Distandrena, Fumandrena and Proxiandrena with A. (Micrandrena); Carandrena with A. (Notandrena); Agandrena with A. (Plastandrena); Geandrena and Xanthandrena with A. (Ptilandrena); Xiphandrena with A. (Scrapteropsis); and Platygalandrena and Poliandrena with A. (Ulandrena) (new synonymies). We additionally reestablish the groups known as Opandrena and Truncandrena as valid subgenera of Andrena. Our results also show that the MRCA of Andrena + Cubiandrena dispersed from the New World to the Palaearctic probably during the Eocene-early Oligocene, followed by 10-14 Neogene dispersal events from the Palaearctic to the Nearctic and 1-6 Neogene dispersals back into the Palaearctic, all within the genus Andrena.

Anchored Phylogenomics, Evolution and Systematics of Elateridae: Are All Bioluminescent Elateroidea Derived Click Beetles?

Click-beetles (Coleoptera: Elateridae) are an abundant, diverse, and economically important beetle family that includes bioluminescent species. To date, molecular phylogenies have sampled relatively few taxa and genes, incompletely resolving subfamily level relationships. We present a novel probe set for anchored hybrid enrichment of 2260 single-copy orthologous genes in Elateroidea. Using these probes, we undertook the largest phylogenomic study of Elateroidea to date (99 Elateroidea, including 86 Elateridae, plus 5 non-elateroid outgroups). We sequenced specimens from 88 taxa to test the monophyly of families, subfamilies and tribes. Maximum likelihood and coalescent phylogenetic analyses produced well-resolved topologies. Notably, the included non-elaterid bioluminescent families (Lampyridae + Phengodidae + Rhagophthalmidae) form a clade within the otherwise monophyletic Elateridae, and Sinopyrophoridae may not warrant recognition as a family. All analyses recovered the elaterid subfamilies Elaterinae, Agrypninae, Cardiophorinae, Negastriinae, Pityobiinae, and Tetralobinae as monophyletic. Our results were conflicting on whether the hypnoidines are sister to Dendrometrinae or Cardiophorinae + Negastriinae. Moreover, we show that fossils with the eucnemid-type frons and elongate cylindrical shape may belong to Eucnemidae, Elateridae: Thylacosterninae, ancestral hard-bodied cantharoids or related extinct groups. Proposed taxonomic changes include recognition of Plastocerini as a tribe in Dendrometrinae and Hypnoidinae stat. nov. as a subfamily within Elateridae.

An annotated and illustrated checklist of Microgastrinae wasps (Hymenoptera, Braconidae) from the Canadian Arctic Archipelago and Greenland.

The Microgastrinae (Hymenoptera: Braconidae) from ten islands of the Canadian Arctic Archipelago (CAA) and Greenland were studied based on 2,183 specimens deposited in collections. We report a total of 33 species in six genera, more than doubling the totals previously known. Most of the species (75.7%) have a distribution restricted to the Nearctic, with nine of those (27.3%) confirmed to be High Arctic endemics and another 10 species considered very likely to be High Arctic endemics as well - accounting for all of those, more than half of all species found are endemic to the region. The most diverse genera were Cotesia (10 species), Glyptapanteles (9 species), and Microplitis (7 species), representing 78.8% of the overall species diversity in the region. The six most frequently collected species comprised 84.7% of all examined specimens. The flight period for Microgastrinae in the High Arctic encompasses only two months, with activity peaking during the first half of July, when almost 40% of all available specimens were collected, and then plummeting in the first half to the end of August. Microgastrinae wasps from the High Arctic are currently known to parasitize eight species within four families of Lepidoptera: three species of Noctuidae, two each of Lymantridae and Nymphalidae, and one species of Pterophoridae. However, that information is very preliminary, as only six of the 33 species of microgastrines currently have associated host data. An annotated checklist, including photographs for 24 of the 33 species, is provided, as well as a key to all Microgastrinae genera present in the region.