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AbstractThe order Hymenoptera is one of the most species-rich insect orders, with more than 150,000 described extant species. Many hymenopteran insects have very different mitochondrial genome (mitogenome) organizations compared to the putative ancestral organization of insects. In this study, we sequenced 18 mitogenomes of representatives in the order Hymenoptera to increase taxonomic sampling. A total of 475 species were used in phylogenetic analyses, including 18 new mitogenomes and 457 existing mitogenomes. Using a site-heterogeneous model, Bayesian’s inference from amino acid data yielded more resolved relationships among Hymenoptera than maximum-likelihood analysis and coalescent-based species analyses. The monophyly of Symphyta was not supported. The Xyeloidea was the earliest branching clade in the Hymenoptera. The Orussoidea was closely related to Apocrita. Within Apocrita, the Parasitoida was non-monophyletic. The monophyly of most Parasitoida superfamilies received strong support. The Proctotrupomorpha clade was supported in Bayesian’s analysis. The Apoidea was monophyletic when excluding Ampulex compressa from consideration. The superfamilies Vespoidea and Chrysidoidea were found to be non-monophyletic. Comparisons of mitochondrial gene order revealed a higher frequency of gene rearrangement among lineages with a parasitoid lifestyle, particularly prominent in Chalcidoidea. The degree of gene rearrangement ranked second in specific taxa of Cynipoidea and Ichneumonoidea. [ABSTRACT FROM AUTHOR]

Adaptive evolution following colonization can affect the impact of invasive species. The fall webworm (FWW) invaded China 40 years ago through a single introduction event involving a severe bottleneck and subsequently diverged into two genetic groups. The well‐recorded invasion history of FWW, coupled with a clear pattern of genetic divergence, provides an opportunity to investigate whether there is any sign of adaptive evolution following the invasion. Based on genome‐wide SNPs, we identified genetically separated western and eastern groups of FWW and correlated spatial variation in SNPs with geographical and climatic factors. Geographical factors explained a similar proportion of the genetic variation across all populations compared with climatic factors. However, when the two population groups were analysed separately, environmental factors explained more variation than geographical factors. SNP outliers in populations of the western group had relatively stronger response to precipitation than temperature‐related variables. Functional annotation of SNP outliers identified genes associated with insect cuticle protein potentially related to desiccation adaptation in the western group and genes associated with lipase biosynthesis potentially related to temperature adaptation in the eastern group. Our study suggests that invasive species may maintain the evolutionary potential to adapt to heterogeneous environments despite a single invasion event. The molecular data suggest that quantitative trait comparisons across environments would be worthwhile. [ABSTRACT FROM AUTHOR]

The genome-level features are crucial genetic resources for species identification and phylogenetic analysis. Here, the complete mitochondrial genome of Aphidius colemani Viereck 1912 (Hymenoptera: Braconidae: Aphidiinae) was sequenced, determined and analyzed. The circular genome is 16,372 bp in length with an overall base composition of 38.9% for A, 46.2% for T, 6.7% for C, and 8.2% for G. The mitochondrial genome of A. colemani contained 13 protein-coding genes that initiated by the ATN codon, 22 transfer RNA genes, two ribosomal RNA genes (rRNAs), and a control region (CR). It shared the same gene arrangement patterns that occurred in two tRNA clusters of trnI-trnQ-trnM and trnW-trnC-trnY with Aphidius gifuensis. Phylogenetic analyses using Bayesian inference and Maximum-likelihood methods supported that the two species of Aphidiinae formed a clade and sister to other subfamilies of Braconidae. [ABSTRACT FROM AUTHOR]

The barley yellow dwarf virus (BYDV) of cereals is thought to substantially increase the high-temperature tolerance of its aphid vector, Rhopalosiphum padi, which may enhance its transmission efficiency. This is based on experiments with North American strains of BYDV and R. padi. Here, we independently test these by measuring the temperature tolerance, via Critical Thermal Maximum (CTmax) and knockdown time, of Australian R. padi infected with a local BYDV isolate. We further consider the interaction between BYDV transmission, the primary endosymbiont of R. padi (Buchnera aphidicola), and a transinfected secondary endosymbiont (Rickettsiella viridis) which reduces the thermotolerance of other aphid species. We failed to find an increase in tolerance to high temperatures in BYDV-infected aphids or an impact of Rickettsiella on thermotolerance. However, BYDV interacted with R. padi endosymbionts in unexpected ways, suppressing the density of Buchnera and Rickettsiella. BYDV density was also fourfold higher in Rickettsiella-infected aphids. Our findings indicate that BYDV does not necessarily increase the temperature tolerance of the aphid transmission vector to increase its transmission potential, at least for the genotype combinations tested here. The interactions between BYDV and Rickettsiella suggest new ways in which aphid endosymbionts may influence how BYDV spreads, which needs further testing in a field context. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pesticide resistance is a long‐standing and growing problem in the chemical control of invertebrate pests. Molecular diagnostic methods can facilitate pesticide resistance management by accurately and efficiently detecting resistant mutations and their frequency. In this study, the kompetitive allele specific PCR (KASP) approach, a technology for high‐throughput single nucleotide polymorphism (SNP) genotyping, is validated as a useful method for characterizing genotypes at a pesticide‐resistance locus for the first time. We focus on the spinetoram resistance mutation of G275E in the nicotinic acetylcholine receptor alpha 6 (nAChR α6) subunit gene of Thrips palmi. RESULTS: Of the 341 individuals of Thrips palmi tested, 98.24% were successfully genotyped, with 100% concordance with Sanger sequencing results. We then quantitatively mixed genomic DNA of known genotypes to establish 21 DNA mixtures with a resistant allele frequency ranging from 0 to 100% at steps of 5%. The linear discriminant analysis (LDA) showed that 75.8% of original grouped cases were correctly classified; six groups had no overlap in membership (resistant allele frequency: 0%, 5%, 10–75%, 80–85%, 90–95%, and 100%). When we chose 11 pooled samples with 10% steps for LDA, 84.4% of original grouped cases were correctly classified; seven groups had no overlap in membership (0%, 10%, 20–30%, 40–70%, 80%, 90%, 100%). The results indicated that KASP applied to pooled samples may provide a semi‐quantitative estimate of resistance. CONCLUSIONS: Our study points to the suitability of KASP for high‐throughput genotyping of genotypes affecting pesticide resistance and semi‐quantitative assessments of resistance allele frequencies in populations. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]