Speciation in kleptoparasites of oak gall wasps often correlates with shifts into new tree habitats, tree organs, or gall morphospace.

Host shifts to new plant species can drive speciation for plant-feeding insects, but how commonly do host shifts also drive diversification for the parasites of those same insects? Oak gall wasps induce galls on oak trees and shifts to novel tree hosts and new tree organs have been implicated as drivers of oak gall wasp speciation. Gall wasps are themselves attacked by many insect parasites, which must find their hosts on the correct tree species and organ, but also must navigate the morphologically variable galls with which they interact. Thus, we ask whether host shifts to new trees, organs, or gall morphologies correlate with gall parasite diversification. We delimit species and infer phylogenies for two genera of gall kleptoparasites, Synergus and Ceroptres, reared from a variety of North American oak galls. We find that most species were reared from galls induced by just one gall wasp species, and no parasite species was reared from galls of more than four species. Most kleptoparasite divergence events correlate with shifts to non-ancestral galls. These shifts often involved changes in tree habitat, gall location, and gall morphology. Host shifts are thus implicated in driving diversification for both oak gall wasps and their kleptoparasitic associates.

Discovery through iNaturalist: new species and new records of oak gall wasps (Hymenoptera: Cynipidae: Cynipini) from Texas, USA.

A new species of the genus Druon Kinsey, 1937, D. laceyi Zhang, Sasan OKennon sp. nov. is described on host plant Quercus laceyi Small from central Texas. We also re-establish Andricus lustrans Beutenmller, 1913 comb.rev., and transfer Striatoandricus aciculatus (Beutenmller, 1909) comb. nov. from Andricus. Finally, we report a new state and host record for Druon gregori Melika, Nicholls Stone, 2022. All observations were first shared on the social platform iNaturalist, highlighting the potential of cybertaxonomy in uncovering overlooked biodiversity.

Speciation in Nearctic oak gall wasps is frequently correlated with changes in host plant, host organ, or both.

Quantifying the frequency of shifts to new host plants within diverse clades of specialist herbivorous insects is critically important to understand whether and how host shifts contribute to the origin of species. Oak gall wasps (Hymenoptera: Cynipidae: Cynipini) comprise a tribe of ∼1000 species of phytophagous insects that induce gall formation on various organs of trees in the family Fagacae-primarily the oaks (genus Quercus; ∼435 sp.). The association of oak gall wasps with oaks is ancient (∼50 my), and most oak species are galled by one or more gall wasp species. Despite the diversity of both gall wasp species and their plant associations, previous phylogenetic work has not identified the strong signal of host plant shifting among oak gall wasps that has been found in other phytophagous insect systems. However, most emphasis has been on the Western Palearctic and not the Nearctic where both oaks and oak gall wasps are considerably more species rich. We collected 86 species of Nearctic oak gall wasps from most of the major clades of Nearctic oaks and sequenced >1000 Ultraconserved Elements (UCEs) and flanking sequences to infer wasp phylogenies. We assessed the relationships of Nearctic gall wasps to one another and, by leveraging previously published UCE data, to the Palearctic fauna. We then used phylogenies to infer historical patterns of shifts among host tree species and tree organs. Our results indicate that oak gall wasps have moved between the Palearctic and Nearctic at least four times, that some Palearctic wasp clades have their proximate origin in the Nearctic, and that gall wasps have shifted within and between oak tree sections, subsections, and organs considerably more often than previous data have suggested. Given that host shifts have been demonstrated to drive reproductive isolation between host-associated populations in other phytophagous insects, our analyses of Nearctic gall wasps suggest that host shifts are key drivers of speciation in this clade, especially in hotspots of oak diversity. Although formal assessment of this hypothesis requires further study, two putatively oligophagous gall wasp species in our dataset show signals of host-associated genetic differentiation unconfounded by geographic distance, suggestive of barriers to gene flow associated with the use of alternative host plants.

Population Structure and Genetic Diversity of the Pepper Weevil (Coleoptera: Curculionidae) Using the COI Barcoding Region.

The pepper weevil Anthonomus eugenii Cano (Coleoptera: Curculionidae) is a pest of economic importance for Capsicum species pepper in North America that attacks the reproductive structures of the plant. The insect is distributed across Mexico, the United States, and the Caribbean, and is occasionally found during the pepper growing season in southern Ontario, Canada. Continuous spread of the insect to new areas is partially the result of global pepper trade. Here, we describe the genetic diversity of the pepper weevil using the mitochondrial COI barcoding region across most of its geographic range. In this study, 44 (H1-H44) highly similar haplotypes were identified, the greatest number of haplotypes and haplotype diversity were observed among specimens from its native Mexico, followed by specimens from the United States. Unlike Mexico, a low haplotype diversity was found among specimens from Canada, the Dominican Republic, Italy, and the Netherlands. Out of these 44 haplotypes, 29 are reported for the first time. Haplotype diversity in the Canadian population suggests either multiple and continuous introductions of the pepper weevil into this area or a single introduction of genetically diverse individuals. We discuss the importance of such population genetic data in tailoring pepper weevil management programs, using Canada as an example.

The Arthropod Associates of 155 North American Cynipid Oak Galls.

The identities of most arthropod associates of cynipid-induced oak galls in the western Palearctic are generally known. However, a comprehensive accounting of associates has been performed for only a small number of the galls induced by the estimated 700 species of cynipid gall wasps in the Nearctic. This gap in knowledge stymies many potential studies of diversity, coevolution, and community ecology, for which oak gall systems are otherwise ideal models. We report rearing records of insects and other arthropods from more than 527,306 individual galls representing 201 different oak gall types collected from 32 oak tree species in North America. Of the 201 gall types collected, 155 produced one or more arthropods. A total of 151,075 arthropods were found in association with these 155 gall types, and of these 61,044 (40.4%) were gall wasps while 90,031 (59.6%) were other arthropods. We identified all arthropods to superfamily, family, or, where possible, to genus. We provide raw numbers and summaries of collections, alongside notes on natural history, ecology, and previously published associations for each taxon. For eight common gall-associated genera (Synergus, Ceroptres, Euceroptres, Ormyrus, Torymus, Eurytoma, Sycophila, and Euderus), we also connect rearing records to gall wasp phylogeny, geography, and ecology -including host tree and gall location (host organ), and their co-occurrence with other insect genera. Though the diversity of gall wasps and the large size of these communities is such that many Nearctic oak gall-associated insects still remain undescribed, this large collection and identification effort should facilitate the testing of new and varied ecological and evolutionary hypotheses in Nearctic oak galls.

UCE data reveal multiple origins of rose gallers in North America: Global phylogeny of Diplolepis Geoffroy (Hymenoptera: Cynipidae).

Gall wasps in the genus Diplolepis Geoffroy are specialized herbivores that induce galls exclusively on roses. Despite their wide distribution across the Holarctic, little is known about their evolutionary history. Here we present the first phylogenomic tree of global Diplolepis reconstructed using Ultraconserved Elements (UCEs), resulting in a robust phylogeny based on 757 genes. Results support the existence of two principal clades: a Nearctic stem-galler clade, and a Holarctic leaf-galler clade that further splits into two Palearctic groups and one Nearctic group. This topology is congruent with a previous study based on the mitochondrial gene COI, an unexpected result given the common occurrence of mitonuclear discordance in closely related oak gall wasp lineages. Most Diplolepis species were recovered as reciprocally monophyletic, with some notable exceptions such as the D. polita and the D. ignota complex, for which species boundaries remain unresolved. Historical biogeographic reconstruction was unable to pinpoint the origin of Diplolepis, but confirms two independent incursions into the Nearctic. Ancestral state reconstruction analysis highlights the conservatism of gall location on the host plants, as shifts to different host organs are relatively rare. We suggest that Diplolepis were originally leaf gallers, with a Nearctic stem-galler clade undergoing a major plant organ switch onto rose stems. Host organ switch or reversal is uncommon, which suggests a level of conservatism. Our study showcases the resolving power of UCEs at the species level while also suggesting improvements to advance future Cynipoidea phylogenomics. Our results also highlight the additional sampling needed to clarify taxonomic relationships in the Nearctic and eastern Palearctic regions.

Integrating multiple sources of biodiversity information greatly expands the range of a rare species of Hymenoptera (Vanhorniidae).

BACKGROUND: Vanhornia eucnemidarum Crawford is the only species of Vanhorniidae that occurs in North America. This species is rarely collected and thus the distribution is not well documented. Intending to uncover a more accurate range of this species, we assembled collection records from museums, personal collections and citizen science projects. Many of these records were non-digitised and had to be personally requested. NEW INFORMATION: Here we expand the known distribution of V. eucnemidarum to include nine new provinces and states: Manitoba, Connecticut, Oregon, Mississippi, Missouri, New Hampshire, New Jersey, Texas and Wisconsin. Although Quebec has been listed as a previous locality, the recorded province was mislabelled, so Quebec is now also officially a provincial record.

Habitat or temporal isolation: Unraveling herbivore-parasitoid speciation patterns using double digest RADseq.

Ecological speciation is often observed in phytophagous insects and their parasitoids due to divergent selection caused by host-associated or temporal differences. Most previous studies have utilized limited genetic markers or distantly related species to look for reproductive barriers of speciation. In our study, we focus on closely related species of Lygus bugs and two sister species of Peristenus parasitoid wasps. Using mitochondrial DNA COI and genomewide SNPs generated using ddRADseq, we tested for potential effects of host-associated differentiation (HAD) or temporal isolation in this system. While three species of Lygus are clearly delineated with both COI and SNPs, no evidence of HAD or temporal differentiation was detected. Two Peristenus sister species were supported by both sets of markers and separated temporally, with P. mellipes emerging early in June and attacking the first generation of Lygus, while P. howardi emerging later in August and attacking the second generation of their hosts. This is one of the few studies to examine closely related hosts and parasitoids to examine drivers of diversification. Given the results of this study, the Lygus-Peristenus system demonstrates temporal isolation as a potential barrier to reproductive isolation for parasitoids, which could indicate higher parasitoid diversity in regions of multivoltine hosts. This study also demonstrates that incorporating systematics improves studies of parasitoid speciation, particularly by obtaining accurate host records through rearing, carefully delimiting cryptic species and examining population-level differences with genomic-scale data among closely related taxa.

Description of a new species of Euderus Haliday from the southeastern United States (Hymenoptera, Chalcidoidea, Eulophidae): the crypt-keeper wasp.

A new species of the genus Euderus Haliday, Euderus setsp. n., is described and illustrated from the southeastern United States, where it parasitizes the crypt gall wasp, Bassettia pallida Ashmead, 1896, on live oaks in the genus Quercus (subsection Virentes). This is the 1st species of the genus reported from the southeastern United States to parasitize cynipid gall wasps and the 3rd species of the genus reported to attack cynipids in North America. Modified sections of the identification keys to subgenera and species of Euderus (Yoshimoto, 1971) are included to integrate the new species.

A new Australian genus and five new species of Rogadinae (Hymenoptera: Braconidae), one reared as a gregarious endoparasitoid of an unidentified limacodid (Lepidoptera) .

Teresirogas Quicke & Shaw gen. nov. (type species T. australicolorus Quicke & Shaw sp. nov.) is described and illustrated, based on a series recently reared gregariously from a cocooned mummy of an unidentified species of Limacodidae collected under loose Eucalyptus bark in New South Wales, Australia. Older reared and unreared congeneric specimens represent four additional species, T. billbrysoni Quicke & van Achterberg sp. nov., T. nolandi Quicke & Butcher sp. nov., T. prestonae Quicke & van Achterberg sp. nov., and T. williamsi Quicke & van Achterberg sp. nov., which are also described and illustrated. Three of these additional species have also been reared from Limacodidae cocoons on Eucalyptus, with one, perhaps erroneous, record suggesting a saturniid host. Molecular analysis confirms the placement of the new type species of Teresirogas in the tribe Rogadini, as inferred initially from the claws with pointed basal lobe and host relationships of some of the species, but one species has the claw character poorly developed which had made its affinities uncertain before the more recently reared and sequenceable material became available.

New species of Eudiospilus (Braconidae, Brachistinae) from Madagascar with a review of the genus and key to species.

A second species of Eudiospilus Szépligeti collected from Madagascar, E. rubrumbarus sp.n., is described with an illustrated key to the two known species. Eudiospilus rubrumbarus can be distinguished from E. conradti Szépligeti by the presence of fore wing vein 2a, hind wing with 2-1A short and not reaching wing margin, propodeum without median furrow, ovipositor longer than total length of body, and differences in the coloration of antennal flagellomeres, head, and metasoma. The evolutionary relationship between Eudiospilus and other diospiline genera is discussed.