Four complete mitogenomes of Eysarcoris rosaceus, E. montivagus, E. gibbosus, E. annamita and one near-complete mitochondrial genome of E. ventralis were sequenced and used to explore the phylogenetic relationships of tribes within the subfamily Pentatominae. The mitogenomes range from 15,422 to 16,043 base pairs (bp) in length and encode 37 genes, including 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes (21 in E. ventralis), and a control region. Similar to other heteropteran species, the AT contents of the sequenced species were higher than their GC contents. The most frequently used start/stop codon was ATN/TAA. GTG was only found in atp6 and atp8 of E. gibbosus. All transfer RNA genes (tRNAs) exhibit the typical cloverleaf secondary structure, except for the trnS1 and trnV, which lacks the stem of the DHU arm. The length and copy number of repeat units were conserved within Eysarcoris, with the exception of E. gibbosus. Phylogenetic analyses based on mitogenomes using both maximum likelihood (ML) and Bayesian inference (BI) methods strongly supported the relationship among tribes within Pentatominae and confirmed that Graphosoma should be an intermediate lineage of Pentatominae. The relationship between Eysarcoris and Carbula was strongly supported and combined with our previous geometric morphometrics and chromosomal studies, suggest the Eysarcoris should belong to the tribe Eyasrcorini. This work will help to enhance our understanding of mitochondrial genomic evolution and phylogenetic relationships in Pentatominae.

Insects are the richest and most diverse group of animals and yet there remains a lack, not only of systematic research into their distribution across some key regions of the planet, but of standardized sampling strategies for their study. The Yanshan Mountains, being the boundary range between the Inner Mongolian Plateau and the North China Plain, present an indispensable piece of the insect biodiversity puzzle: both requiring systematic study and offering opportunities for the development of standardized methodologies. This is the first use of DNA metabarcoding to survey the insect biodiversity of the Yanshan Mountains. The study focuses on differences of community composition among samples collected via different methods and from different habitat types. In total, 74 bulk samples were collected from five habitat types (scrubland, woodland, wetland, farmland and grassland) using three collection methods (sweep netting, Malaise traps and light traps). After DNA extraction, PCR amplification, sequencing and diversity analysis were performed, a total of 7427 Operational Taxonomic Units (OTUs) at ≥97% sequence similarity level were delimited, of which 7083 OTUs were identified as belonging to Insecta. Orthoptera, Diptera, Coleoptera and Hemiptera were found to be the dominant orders according to community composition analysis. Nonmetric multidimensional scaling (NMDS) analysis based on Bray–Curtis distances revealed highly divergent estimates of insect community composition among samples differentiated by the collection method (R = .524802, p = .001), but nonsignificant difference among samples differentiated according to habitat (R = .051102, p = .078). The study therefore appears to indicate that the concurrent use of varied collection methods is essential to the accurate monitoring of insect biodiversity.

Callosobruchus chinensis (Coleoptera Bruchidae), is a pest of different varieties of legumes. In this paper, a phylogeographical analysis of C. chinensis was conducted to provide knowledge for the prevention and control of C. chinensis. A total of 224 concatenated mitochondrial sequences were obtained from 273 individuals. Suitable habitat shifts were predicted by the distribution modelling (SDM). Phylogeny, genetic structure and population demographic history were analyzed using multiple software. Finally, the least-cost path (LCP) method was used to identify possible dispersal corridors and genetic connectivity. The SDM results suggested that the distribution of C. chinensis experienced expansion and contraction with changing climate. Spatial distribution of mtDNA haplotypes showed there was partial continuity among different geographical populations of C. chinensis, except for the Hohhot (Inner Mongolia) population. Bayesian skyline plots showed that the population had a recent expansion during 0.0125 Ma and 0.025 Ma. The expansion and divergent events were traced back to Quaternary glaciations. The LCP method confirmed that there were no clear dispersal routes. Our findings indicated that climatic cycles of the Pleistocene glaciations, unsuitable climate and geographic isolation played important roles in the genetic differentiation of C. chinensis. Human activities weaken the genetic differentiation between populations. With the change in climate, the suitable areas of C. chinensis will disperse greatly in the future.

In pyrrhocorids, digestion of food occurs mainly in the midgut, which is divided into four parts (M1-M4), and takes between three and four days. Food is retained in M1 for about 5 h and passes quickly through M4. However, food is retained in M2 and M3 much longer, about 70 to 90 h. The different stages in digestion may be influenced by different microbial populations in the different parts of the midgut. In the present study, the microbiota in the four parts of the midgut of Pyrrhocoris sibiricus were analysed in detail using high-throughput sequencing of the 16S rRNA V3-V4 region. The most abundant bacteria in M3 were Actinobacteria (Coriobacteriaceae) whereas it was Proteobacteria (gammaproteobacteria) in M1, M2 and M4. Actinobacteria was the second most abundant bacterial group in M2. According to the PCA analysis, M2 and M3 have the most similar bacterial communities. Burkholderia, which is closely related to the plant-associated beneficial and environmental (PBE) group, was also found in M1, M2 and M4. Predictive functional profiles of the metagenomes revealed that metabolism mostly occurred in M2 and M3. The PICRUSt results were consistent with the 16S rRNA metagenomic analysis and indicate that the bacteria in M2 and M3 play an important role in degrading complex dietary components.

The complete mitochondrial genome of Notonecta amplifica Kiritshenko, 1930 (Hemiptera: Notonectidae) was sequenced by high-throughput sequencing (HTS). The whole length is 15,150 bp, including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNAs), two ribosomal RNA (rRNAs) and a 528 bp control region (D-loop). The nucleotide is with a base composition of A (43.01%), G (10.32%), C (13.87%) and T (32.80%). The total length of the coding sequences encoding 3,694 amino acids is 11,113 bp, accounting for 73.35%. The lengths of 12S rRNA and 16S rRNA are 800 and 1,251 bp, respectively. The Bayesian phylogenetic analysis of 20 taxa indicate that N. amplifica is closely related to Notonecta montandoni, with posterior probability value of 1.00. The complete mitochondrial genome sequence would provide useful genetic information for future taxonomic and phylogenetic classification of N. amplifica.