Yuanmeng Miles Zhang

Understanding how specialized herbivores track divergence among their hosts is central to evolutionary biology. Congruent genetic structure between hosts and herbivores is often interpreted as evidence of long-term codivergence, but similar patterns may also arise when herbivores rapidly adapt to pre-existing host differentiation. Here, we integrate population genomics, host volatile profiling, and behavioral assays to examine host-associated divergence in the obligate seed-feeding wasp Megastigmus daduheensis and its conifer host Cupressus chengiana across three river valleys on the eastern Qinghai-Tibet Plateau. Despite strong phylogeographic congruence between each of the three wasp and host lineages, calibrated demographic analyses indicate that wasp divergence occurred during the early Holocene, substantially later than the Pliocene-Pleistocene divergence of host lineages. This temporal mismatch is inconsistent with strict long-term codivergence and instead supports rapid host tracking in a topographic complex region. Host lineages differed in volatile organic compound profiles, and behavioral assays showed that wasps were preferentially attracted to volatiles from their local host lineages. These results identify olfactory-mediated host recognition as a plausible mechanism promoting host fidelity and reinforcing host-associated genomic and behavioral differentiation. Our findings show that apparently concordant host-herbivore divergence can emerge over compressed evolutionary timescales through rapid local adaptation, highlighting how ecological differentiation can accumulate within species through host tracking.

Gall-inducing wasps are emerging models for studying plantinsect coevolution, host manipulation, host plant adaptation, and speciation, yet chromosome-level resources remain scarce for most lineages. The blueberry stem gall wasp (BSGW), Hemadas nubilipennis (Hymenoptera: Ormyridae), is native to North America where it induces galls on both lowbush (Vaccinium angustifolium) and highbush blueberries (V. corymbosum). Recently, BSGW has reached outbreak densities in cultivated highbush production. Given that (a) the biology has been characterized primarily from natural lowbush-associated populations, (b) the absence of genomic resources limits comparative analyses, and (c) populations on cultivated highbush represent a recent host shift, we generated the first chromosome-level genome from wild lowbush blueberry. The BSGW genome consists of five chromosome-scale scaffolds totaling 1.08 Gb (N50 = 218 Mb), the second largest known in Chalcidoidea. Comparative analysis reveals that genome size variation is driven primarily by transposable element proliferation (R = 0.96, p < 0.001), with BSGW exhibiting a high proportion of unclassified TEs. Gene-body methylation is conserved, enriched in exons of broadly expressed core genes, and correlates with gene density. The mitochondrial genome (18,697 bp) exhibits extensive gene rearrangement, and COI sequences reveal 4.35.4% divergence from geographically distant populations, suggesting a complex of cryptic species. Additionally, we assemble a near-complete genome of the endosymbiont Wolbachia pipientis (Supergroup A), which encodes PifA and PifB effectors potentially linked to parthenogenesis. These resources establish a foundation for population genomics, taxonomic revision, and applied management, while providing insights into genome architecture, epigenetics, and symbiont interactions.

The genus Aximopsis sensu lato (Hymenoptera, Eurytomidae) is a cosmopolitan group of parasitoid wasps, currently comprising 43 described species. The genus is defined by a suite of homoplastic morphological characters and its taxonomic boundaries remain unstable, with recent molecular phylogenies indicating paraphyly. The nodularis species group, which accounts for approximately half of the known species, includes parasitoids of various endophytic insects. While host associations with small carpenter bees of the genus Ceratina (Apidae) have been documented for a few eurytomid species in Europe and North America, no species of Aximopsis s.l. has ever been recorded from China. A new species of Aximopsis Ashmead, Aximopsis qiong Li, Zhang & Chen sp. nov. (Hymenoptera, Chalcidoidea, Eurytomidae) is described from Hainan, China. The species was reared as a gregarious ectoparasitoid of the small carpenter bee Ceratina smaragdula (Fabricius) (Hymenoptera, Apidae). The new species is provisionally placed in Aximopsis sensu lato and tentatively assigned to the nodularis species group based on morphological characters. Diagnostic characters, detailed morphology, biological observations and illustrations of both sexes are provided. Molecular phylogenetic analysis, based on COI sequences,failed to recover Aximopsis sensu lato as monophyletic, supporting previous evidence of its uncertain generic boundaries. This discovery represents the first record of the genus Aximopsis from China and only the second confirmed species of the nodularis group associated with Ceratina hosts. Collectively, our finding expand the known distribution and host range of this parasitoid lineage, while also underscoring the pressing need for a comprehensive taxonomic revision of Aximopsis sensu lato .

The Erythrina gall wasp, Quadrastichus erythrinae, is an invasive gall-inducing chalcidoid wasp and a major pest of the endemic wiliwili tree (Erythrina sandwicensis) in Hawai’i. As a foundation for associated research, we generated a chromosome-level genome assembly from a wild-collected female measuring <2 mm. The final assembly consists of 5 scaffolds representing the 5 autosomes totaling 399 Mb (N50 = 75.6 Mb) and 1 unplaced 16 kb contig. BUSCO analysis recovers 91.1% of conserved Hymenoptera orthologs, representing the first chromosome-scale genome for the genus Quadrastichus. Comparative genomic analyses reveal syntenic conservation across Hymenoptera despite deep evolutionary divergence, with strongest collinearity to the chalcidoid Nasonia vitripennis. Genome size variation is largely explained by repeat content, and Q. erythrinae exhibits high proportions of unclassified transposable elements similar to the cynipid gall inducer. We also assembled a complete genome of its endosymbiont, Wolbachia pipientis. Together, these genomic resources provide a foundation for comparative, evolutionary, and applied research aimed at managing this invasive pest.

Five new species of oak gall wasps of the genus Amphibolips Reinhard, 1865 (Cynipidae, Cynipini) are described from Mexico. Amphibolips megalokokka Nieves-Aldrey & Castillejos-Lemus sp. nov. and Amphibolips oyamai Castillejos-Lemus & Nieves-Aldrey sp. nov. from the Trans-Mexican Volcanic Belt (TMVB) exhibit unique morphological characteristics within the genus, particularly in gall morphology. Three additional species, Amphibolips zapoteco Nieves-Aldrey & Castillejos-Lemus sp. nov., Amphibolips idiopteryx Nieves-Aldrey & Castillejos-Lemus sp. nov. and Amphibolips darioi Castillejos-Lemus & Nieves-Aldrey sp. nov., are described from Oaxaca State. These Oaxacan species show remarkable morphological similarity while providing important insights into the relationships among species within the Oaxacan clade. Based on a prior phylogenetic study using ultraconserved elements, we describe these five new species with supporting evidence from both morphology and molecular data. We also examined the great morphological variation in Trans-Mexican Volcanic Belt species, including both generations of one species, and discusses species richness, phylogenetic relationships, and taxonomic challenges within the genus.

Belonocnema Mayr (Cynipidae, Cynipini) is an oak gall wasp genus currently known by three described species distributed in the southern and southeastern U.S. and northern Mexico, all associated with live oaks of the Quercus section Virentes. Here, we conducted an integrative systematic study of a new species of Belonocnema , B. mesoamericana Zhang, Zaldívar-Riverón & Fernández-Flores, sp. nov ., reared from galls of the live oak Quercus oleoides Schltdl. in the state of Veracruz, Mexico. We morphologically described the sexual and asexual generations of the new species and their galls, molecularly characterized it based on the DNA barcoding locus, reconstructed its phylogenetic affinities using multilocus data from Ultraconserved Elements, and identified its associated hymenopteran community. The new species is morphologically similar to its sister species, B. kinseyi Weld, though it can be distinguished by color and sculpture features, as well as by the sexual generation forming velvety rootlet galls. Since Q. oleoides is widely distributed across Mesoamerica, we expect the new species to have a broader distribution. A considerably high species richness and phylogenetic diversity of the hymenopteran community associated with the galls were recovered, with 43 morphospecies belonging to 15 genera and 13 families, of which 41 were found in the asexual generation and only three in the sexual generation. This study increases the systematic knowledge of a poorly known Cynipini genus and highlights the extraordinary, yet neglected, insect diversity associated with galls, especially in the Neotropics.

The erythrina gall wasp, Quadrastichus erythrinae , is an invasive gall-inducing chalcidoid wasp and a major pest of the endemic wiliwili tree ( Erythrina sandwicensis ) in Hawai□i. As a foundation to associated research, we generated a chromosome-level genome assembly from a wild-collected female measuring Quadrastichus . Comparative genomic analyses reveal syntenic conservation across Hymenoptera despite deep evolutionary divergence, with strongest collinearity to the chalcidoid Nasonia vitripennis . Genome size variation is largely explained by repeat content, and Q. erythrinae exhibits high proportions of unclassified transposable elements similar to the cynipid gall inducer. We also assembled a complete genome of its endosymbiont, Wolbachia pipientis . Together, these genomic resources provide a foundation for comparative, evolutionary, and applied research aimed at managing this invasive pest.

Despite concerns from taxonomists, at least 300 plant and fungi names starting with caf[e]r- or caff[e]r- were changed to af[e]r- because of racial offensiveness. This comment offers a chronically overlooked Asian perspective on taxonomic ethics, highlighting gaps in global inclusivity and raising questions about practical challenges.

We describe a new species of rose gall wasp from Sichuan, China, Diplolepis nezha Hu, Zhang, McCormack & Fang, sp. nov. (Diplolepididae: Diplolepidinae), which induces galls on the rare, endemic rose Rosa chinensis var. spontanea (Rehder & E.H. Wilson) T.T. Yu & T.C. Ku. In association with these galls, we also describe a new parasitoid species, Orthopelma aobing Hu, Zhang, Dal Pos, McCormack & Fang, sp. nov. (Ichneumonidae: Orthopelmatinae). DNA barcodes were used to confirm the identities of both new species. We provide updated dichotomous keys incorporating these taxa and briefly discuss their biology in the context of other East Asian species, informed by phylogenetic analyses.