Comparative mitogenomics and phylogenetics of the stinging wasps (Hymenoptera: Aculeata).

The stinging wasps (Hymenoptera: Aculeata) include diverse groups such as vespid wasps, ants and bees. Phylogenetic relationships among major lineages of stinging wasps have been inferred from molecular and morphological data. However, the genomic features of the mitochondrial genomes and their phylogenetic utility remain to be explored. In this study, we determined 23 mitochondrial genomes from the Aculeata. Four Mutillidae species showed relatively low A + T content compared to other species of the Aculeata (69.7%-77.4%). Eleven out of 44 species, mainly from the Chrysididae and the Pompilidae, showed reversals of GC skews. Gene rearrangements occurred across the species. Patterns of tRNA rearrangement were conserved in some groups, including the Chrysididae, Bethylidae, Pompilidae, Scolioidea and Vespoidea. Rearrangement of protein-coding genes were found in 12 out of 44 species of the Aculeata, including all four species from the Chrysididae, both species from the Bethylidae, one species from the Dryinidae, all three Scolioidea species and two Apoidea species. Phylogenetic inference showed a long branch in species with unusual genomic features, such as in the Mutillidae and Bethylidae. By excluding these species, we found paraphyly of the Chrysidoidea and a sister group relationship between the Formicoidea and Vespoidea. These results improve our understanding of the evolution of mitochondrial genomes in the Aculeata and, in general, the evolution across this subclade.

Next-Generation Sequencing of Two Mitochondrial Genomes from Family Pompilidae (Hymenoptera: Vespoidea) Reveal Novel Patterns of Gene Arrangement.

Animal mitochondrial genomes have provided large and diverse datasets for evolutionary studies. Here, the first two representative mitochondrial genomes from the family Pompilidae (Hymenoptera: Vespoidea) were determined using next-generation sequencing. The sequenced region of these two mitochondrial genomes from the species Auplopus sp. and Agenioideus sp. was 16,746 bp long with an A + T content of 83.12% and 16,596 bp long with an A + T content of 78.64%, respectively. In both species, all of the 37 typical mitochondrial genes were determined. The secondary structure of tRNA genes and rRNA genes were predicted and compared with those of other insects. Atypical trnS1 using abnormal anticodons TCT and lacking D-stem pairings was identified. There were 49 helices belonging to six domains in rrnL and 30 helices belonging to three domains in rrns present. Compared with the ancestral organization, four and two tRNA genes were rearranged in mitochondrial genomes of Auplopus and Agenioideus, respectively. In both species, trnM was shuffled upstream of the trnI-trnQ-trnM cluster, and trnA was translocated from the cluster trnA-trnR-trnN-trnS1-trnE-trnF to the region between nad1 and trnL1, which is novel to the Vespoidea. In Auplopus, the tRNA cluster trnW-trnC-trnY was shuffled to trnW-trnY-trnC. Phylogenetic analysis within Vespoidea revealed that Pompilidae and Mutillidae formed a sister lineage, and then sistered Formicidae. The genomes presented in this study have enriched the knowledge base of molecular markers, which is valuable in respect to studies about the gene rearrangement mechanism, genomic evolutionary processes and phylogeny of Hymenoptera.

Extensive gene rearrangements in the mitochondrial genomes of two egg parasitoids, Trichogramma japonicum and Trichogramma ostriniae (Hymenoptera: Chalcidoidea: Trichogrammatidae).

Animal mitochondrial genomes usually exhibit conserved gene arrangement across major lineages, while those in the Hymenoptera are known to possess frequent rearrangements, as are those of several other orders of insects. Here, we sequenced two complete mitochondrial genomes of Trichogramma japonicum and Trichogramma ostriniae (Hymenoptera: Chalcidoidea: Trichogrammatidae). In total, 37 mitochondrial genes were identified in both species. The same gene arrangement pattern was found in the two species, with extensive gene rearrangement compared with the ancestral insect mitochondrial genome. Most tRNA genes and all protein-coding genes were encoded on the minority strand. In total, 15 tRNA genes and seven protein-coding genes were rearranged. The rearrangements of cox1 and nad2 as well as most tRNA genes were novel. Phylogenetic analysis based on nucleotide sequences of protein-coding genes and on gene arrangement patterns produced identical topologies that support the relationship of (Agaonidae + Pteromalidae) + Trichogrammatidae in Chalcidoidea. CREx analysis revealed eight rearrangement operations occurred from presumed ancestral gene order of Chalcidoidea to form the derived gene order of Trichogramma. Our study shows that gene rearrangement information in Chalcidoidea can potentially contribute to the phylogeny of Chalcidoidea when more mitochondrial genome sequences are available.

The mitochondrial genome of the Vespa mandarinia Smith (Hymenoptera: Vespidae: Vespinae) and a phylogenetic analysis of the Vespoidea.

We report the mitochondrial genome of the Vespa mandarinia Smith (GenBank accession no. KR059904) for the subfamily Vespinae (Hymenoptera: Vespidae). This is the first completely sequenced mitochodrial genome from the genus Vespa. All of the typical mitochondrial genes were sequenced with a length of 15 902 bp. In the V. mandarinia mitochondrial genome, four rearrangement events occurred compared with the pupative ancestral arrangement of insects, corresponding to the shuffling of trnQ and trnM, translocation of trnY to the region between A + T-rich region and trnI-trnM-trnQ, shuffling of trnS1 and trnE in the tRNA cluster of trnA-trnR-trnN-trnS1-trnE-trnF, and translocation of trnL1 from a location between nad1 and rrnL to the upstream of nad1 gene. Phylogenetic analysis using the Bayesian method based on all codon positions of the 13 protein-coding genes supports the monophyly of Vespidae and Formicidae. Within the Formicidae, the Myrmicinae and Dolichoderinae form a sister group, while within the Vespidae, the Eumeninae sister to lineage of Vespinae + Polistinae. Our study showed that the mitochondrial genomes between Vespinae and Polistinae shared more arrangement patterns than that between Vespinae and Eumeninae.

The mitochondrial genome of Polistes jokahamae and a phylogenetic analysis of the Vespoidea (Insecta: Hymenoptera).

The mitochondrial genome sequence of Polistes jokahamae (Radoszkowski, 1887) (Hymenoptera: Vespidae) (GenBank accession no. KR052468) was sequenced. The current length with partial A + T-rich region of this mitochondrial genome is 16,616 bp. All the typical mitochondrial genes were sequenced except for three tRNAs (trnI, trnQ, and trnY) located between the A + T-rich region and nad2. At least three rearrangement events occurred in the sequenced region compared with the pupative ancestral arrangement of insects, corresponding to the shuffling of trnK and trnD, translocation or remote inversion of tnnY and translocation of trnL1. All protein-coding genes start with ATN codons. Eleven, one, and another one protein-coding genes stop with termination codon TAA, TA, and T, respectively. Phylogenetic analysis using the Bayesian method based on all codon positions of the 13 protein-coding genes supports the monophyly of Vespidae and Formicidae. Within the Formicidae, the Myrmicinae and Formicinae form a sister lineage and then sister to the Dolichoderinae, while within the Vespidae, the Eumeninae is sister to the lineage of Vespinae + Polistinae.