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Background: Chromosome stability is crucial for homeostasis of pluripotent stem cells (PSCs) and early-stage embryonic development. Chromosomal defects may raise carcinogenic risks in regenerative medicine when using PSCs as original materials. However, the detailed mechanism regarding PSCs chromosome stability maintenance is not fully understood. Methods: Mouse embryonic stem cells (line D3) and human embryonic stem cells (line H9) were cultured under standard conditions. To confirm the loading of RetSat protein on mitotic chromosomes of PSCs, immunostaining was performed in PSCs spontaneous differentiation assay and iPSC reprogramming assay from mouse embryonic fibroblasts (MEFs), respectively. In addition, qPCR, immunoprecipitation, LC-MS/MS and immunoblotting were used to study the expression of RetSat, and interactions of RetSat with cohesin/condensin components. RNA sequencing and teratoma formation assay was conducted to evaluate the carcinogenic risk of mouse embryonic stem cells with RetSat deletion. Results: We reported a PSC high-expressing gene, RetSat, plays key roles in chromosome stabilization. We identified RetSat protein localizing onto mitotic chromosomes specifically in stemness positive cells such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). We found dramatic chromosome instability, e.g. chromosome bridging, lagging and interphase micronuclei in mouse and human ESCs when down regulating RetSat. RetSat knock-out mouse ESCs upregulated cancer associated gene pathways, and displayed higher tumorigenic capacities in teratoma formation assay. Mechanistically, we confirmed that RetSat interacts with cohesin/condensin components Smc1a and Nudcd2. RetSat deletion impaired the chromosome loading dosage of Smc1a, Smc3 and Nudcd2. Conclusions: In summary, we reported RetSat to be a key stabilizer of chromosome condensation in pluripotent stem cells. This highlights the crucial roles of RetSat in early-stage embryonic development, and potential value of RetSat as an effective biomarker for assessing the quality of pluripotent stem cells. [ABSTRACT FROM AUTHOR]

The thread-legged bug genus Onychomesa Wygodzinsky 1966 (Hemiptera: Reduviidae: Emesinae: Emesini, formerly Metapterini) and its three described species are reviewed. The Sri Lankan species Ischnonyctes alatus Distant 1903 is resurrected from the synonymy with Schidium marcidum (Uhler, 1896) and transferred to Onychomesa, and O. susainathani Wygodzinsky, 1966 is considered a junior synonym of this species, resulting in the following taxonomic changes: O. alata (Distant 1903), stat. rev. et comb. nov. = O. susainathani Wygodzinsky 1966, syn. nov. The lectotype of I. alatus is designated. A new species, O. schuhi Chen et Cai, sp. nov., is described from Hainan Island, southern China. An updated key to the species of Onychomesa is provided. The species is registered in ZooBank (http://zoobank.org/8F582127-631F-4CD9-9E02-C3CD14AA52DC). [ABSTRACT FROM AUTHOR]

The hemipteran suborder Auchenorrhyncha consists of four superfamily rank taxa (i.e. Cicadoidea, Membracoidea, Cercopoidea and Fulgoroidea), with more than 42000 described species worldwide. The monophyly of Auchenorrhyncha and the higher-level relationships within this group remain questionable, despite recent research using morphological and molecular data. In this study, we sequenced 18 mitogenomes of representatives of Membracoidea, three of Cercopoidea and one of Psylloidea and conducted phylogenetic analyses together with 35 existing mitogenomes of Hemiptera, with special emphasis on the auchenorrhynchan monophyly. The phylogenetic inferences from the mitogenomic data are strongly affected by increased rates of sequence substitution associated with several lineages, which leads to the significant long-branch attraction. Under these conditions, the monophyly of Auchenorrhyncha is not supported even with the comprehensive data coding schemes. This shows the limitations of the mitogenome in resolving the higher-level phylogeny of Auchenorrhyncha. In addition, the removal of fast-evolving sites using a pattern sorting method (OV-sorting) significantly improves phylogenetic estimates under both homogeneous and heterogeneous models. Moreover, data sets with a higher proportion of conserved sites recover the monophyly of Auchenorrhyncha and support a superfamily relationship of [Fulgoroidea + ((Cicadoidea + Cercopoidea) + Membracoidea)]. [ABSTRACT FROM AUTHOR]

The Chinese fauna represents a small portion of the species diversity of the psyllid genus Pseudophacopteron (Phacopteronidae) of the world. Here, Pseudophacopteron from China is revised, and four species are recognized. Pseudophacopteron quinquipannis sp. nov. is described; Pseudophacopteron alstonium is synonymized with Pseudophacopteron tuberculatum; Pseudophacopteron album, Pseudophacopteron aphanamixis and P. tuberculatum are redescribed. Comparison is made between the four species and Phacopteron. The latter possesses unsplit fields of radular spinules in cells m1, m2 and cu1 of the fore wing, and thick tibiae covered by dense long and slender setae, which are different from Pseudophacopteron. http://www.zoobank.org/urn:lsid:zoobank.org:pub:08B185EB-462F-46CF-B4CB-B733D1E1A864 [ABSTRACT FROM AUTHOR]

Simple Summary: The assassin bug subfamily Stenopodainae is the fifth largest group of Reduviidae, with about 770 valid species known worldwide. Many taxa of Stenopodainae have been poorly studied and are therefore in need of revision. Argolis Stål, 1861 is a medium-sized genus of Stenopodainae with native species occurring in Sub-Saharan Africa and Asia. The Asian fauna of Argolis is revised in this study, resulting in the recognition of two species, and the Oriental genera Bardesanes Distant, 1909 and Neoklugia Distant, 1919 are here considered junior synonyms of Argolis. Taxonomic changes are proposed accordingly in the present study, and the significant sexual dimorphism, systematic relationships, and distribution of Argolis are also discussed. The assassin bug genus Argolis Stål, 1861 (Hemiptera: Reduviidae: Stenopodainae) has a disjunct distribution in Sub-Saharan Africa and Asia. In the present study, the Asian species of Argolis are revised. Two species are recognized, redescribed, and illustrated, with the following new subjective synonyms and new combination proposed: Argolis Stål, 1861 = Bardesanes Distant, 1909, syn. nov. = Neoklugia Distant, 1919, syn. nov.; A. farinator (Reuter, 1882) = N. typica Distant, 1919, syn. nov. = B. sericenotatus Livingstone & Ravichandran, 1989, syn. nov.; A. signata (Distant, 1909), comb. nov. (transferred from Bardesanes) = Caunus noctulus Hsiao, 1977, syn. nov. Lectotypes for C. farinator, B. signatus, and N. typica are designated. A key to separate the two Asian species of Argolis is provided. The sexual dimorphism, systematic relationships, and distribution of Argolis are discussed. Argolis is newly recorded from Laos, Pakistan, and Vietnam. [ABSTRACT FROM AUTHOR]

Summary Blood-feeding insects, as vectors of disease for humans and livestock alike, have garnered significant interest [ 1, 2 ], but our understanding of their early evolution is hindered by the scarcity of available material and the difficulty in distinguishing early hematophages from non-blood-feeding relatives. Here, we report a new family of true bugs including two new genera and species from the Early Cretaceous Yixian Formation in Northeastern China. By utilizing geochemical methods for determining their diets and combining morphological and taphonomic data, we demonstrate that these new species represent the earliest evidence of blood feeding among true bugs, extending the geological record of such lineages by approximately 30 million years. Remarkably, one of the bugs appears to have perished immediately following a blood meal, which may have been from coexisting mammals, birds, or avian-related dinosaurs. These records expand the phylogenetic and ecological diversity of blood-feeding insects in the Early Cretaceous, enriching our knowledge of paleoecological associations in these ancient environments. [ABSTRACT FROM AUTHOR]

A new extinct family of Pentatomoidea, Primipentatomidae fam. nov., with four new genera and five new species (Primipentatoma peregrinagen. et sp. nov.,Primipentatoma fangigen. et sp. nov.,Breviscutum lunatumgen. et sp. nov.,Oropentatoma epicharagen. et sp. nov. andQuadrocoris radiusgen. et sp. nov.), is described from the Upper Mesozoic deposits of north-eastern China. A cladistic analysis based on a combination of fossil and extant morphological characters clarifies the phylogenetic status of the new family and allows reconstruction of the interfamily relationships within the superfamily Pentatomoidea. Major conclusions of the phylogenetic analysis are: (1) the fossils represent a monophyletic group interpreted as the sister group to all Pentatomoidea exclusive of Saileriolidae + Urostylididae; (2) Urostylididaesensu latois a paraphyletic group; (3) monophyly of Acanthosomatidae, Pentatomidae, Thyreocoridae, Dinidoridae, Phloeidae and Scutelleridae are strongly supported by high bootstrap values in the analysis, but the relationships among these families is less resolved; (4) monophyly of the Cydnidae was not supported. The time of origin of Pentatomoidea should be before the Early Cretaceous (125–130 Ma), and may be as early as the Late or Middle Jurassic with a centre of origin in East Asia. http://zoobank.org/urn:lsid:zoobank.org:pub:A432B387-E3A1-42D3-8051-867EB5108318 [ABSTRACT FROM AUTHOR]

Simple Summary: The assassin bug genus, Tympanistocoris Miller, is revised with the redescription of the type species, T. humilis Miller, and the description of a new species, Tympanistocoris usingeri sp. nov., from Papua New Guinea. The morphological comparation and a key are provided to distinguish the two species. The anastomosing veins on the hemelytra and the systematic position of Tympanistocoris are also briefly discussed. The small reduviine genus, Tympanistocoris Miller, is revised. The type species of the genus, T. humilis Miller, is redescribed, and a new species, Tympanistocoris usingeri sp. nov., from Papua New Guinea is described. The illustrations of the antennae, head and pronotum, legs, hemelytra, abdomen, and male genitalia, as well as the habitus of the type specimens are also provided. The new species can be separated from the type species of the genus, T. humilis Miller, in the lateral sides of the pronotum with a distinct carina and the posterior margin of the seventh abdominal segment emarginated. The type specimen of the new species is kept in The Natural History Museum, London. The anastomosing veins of the hemelytra and the systematic position of the genus are briefly discussed. [ABSTRACT FROM AUTHOR]

Abstract: Insect parasitism was known in China for a long time in the form of parasitic tachinid flies of silkworms (Bombyx mori L.). These tachinid flies were first mentioned in the Chinese literature around 300 AD. The developmental cycle of this tachinid (possibly a species of the genus Exorista) were clearly described by Lu Dian in 1096. This antedates the first descriptions of insect parasitoids from Europe by 600 years. Another parasitic fly, a flesh fly (possibly Blaesoxipha lapidosa Pape) was noted as the main parasitoid of Locusta migratoria manilensis Meyen in 1196. The first Chinese record with a correct description of the life cycle of a hymenopteran parasitoid dates from 1704. [Copyright &y& Elsevier]

Simple Summary: The members of the Reduviidae family are generally known as "assassin bugs" due to their predatory habits. Peiratinae is one of the largest subfamilies of Reduviidae with a cosmopolitan distribution. Based on the morphological examination on type specimens and other peiratine material from New Guinea, as well as the result of a molecular phylogenetic analysis using COI, 16S and 18S genes, the subgenus Ectomocoris (Sigicoris) Miller, 1958 is elevated to genus level and revised. Four species are recognized and keyed, including three new combinations: S. brumalis comb. nov., S. gracilis comb. nov., S. sexguttatus comb. nov. and one new species, S. dominiqueae sp. nov. The lectotype is designated for Brachysandalus sexguttatus. Pirates concinnus syn. nov. is treated as the junior synonym of S. sexguttatus comb. nov. The systematic relationships, diagnosis, distribution and habitat of this genus are also discussed. Peiratinae is a cosmopolitan subfamily within Reduviidae with more than 300 known species in 34 genera. There are also some taxa endemic to islands, but their taxonomic status and biology require further study. After examining type specimens of the peiratine species distributed in New Guinea, we found that some of them share many morphological characters, though they were previously assigned in different genera. The phylogenetic analysis based on cytochrome oxidase I, 16S ribosomal RNA and 18S ribosomal RNA genes involving 38 species in 25 genera also supports the result of the morphological study that these species should be involved in a separate genus. In the present study, the subgenus Ectomocoris (Sigicoris) Miller, 1958 is elevated to genus level, Sigicoris stat. nov. Three new combinations, S. brumalis comb. nov., S. gracilis comb. nov., S. sexguttatus comb. nov. and one new species, S. dominiqueae sp. nov. are described or redescribed. The lectotype of Brachysandalus sexguttatus is designated, and Pirates concinnus syn. nov. is treated as the junior synonym of S. sexguttatus comb. nov. A key is provided to separate the four species of this genus. The systematic relationships, diagnosis, distribution and habitat of Sigicoris stat. nov. are briefly discussed. [ABSTRACT FROM AUTHOR]

Adenosine-to-inosine (A-to-I) RNA editing recodes the genetic information. Apart from diversifying the proteome, another tempting advantage of RNA recoding is to correct deleterious DNA mutation and restore ancestral allele. Solid evidences for beneficial restorative editing are very rare in animals. By searching for "convergent recoding" under a phylogenetic context, we proposed this term for judging the potential restorative functions of particular editing site. For the well-known mammalian Gln>Arg (Q>R) recoding site, its ancestral state in vertebrate genomes was the pre-editing Gln, and all 470 available mammalian genomes strictly avoid other three equivalent ways to achieve Arg in protein. The absence of convergent recoding from His>Arg, or synonymous mutations on Gln codons, could be attributed to the strong maintenance on editing motif and structure, but the absence of direct A-to-G mutation is extremely unexpected. With similar ideas, we found cases of convergent recoding in Drosophila genus, reducing the possibility of their restorative function. In summary, we defined an interesting scenario of convergent recoding, the occurrence of which could be used as preliminary judgements for whether a recoding site has a sole restorative role. Our work provides novel insights to the natural selection and evolution of RNA editing. [ABSTRACT FROM AUTHOR]

Simple Summary: This study focuses on the assassin bug Sycanus bifidus, a widespread species in southern China, by analyzing its genetic data to trace how the Pleistocene's climate and geography influenced its distribution and evolution. There are two main genetic groups, which suggests that past climatic conditions and sea-level rises, especially concerning Hainan Island, profoundly impacted the spread and distribution of these bugs. This study's insights into the assassin bugs' historical population dynamics and adaptations to environmental changes emphasize the role of historical climatic fluctuations in shaping the distribution of species. The assassin bug Sycanus bifidus has a wide distribution across southern China. This study explored its distribution and evolution by analyzing mitochondrial and nuclear ribosomal RNA genes, revealing how Pleistocene climate and geological changes shaped its phylogeography. We identified two main clades, A and B, that diverged in the Middle Pleistocene. Hainan Island's populations form a unique group within Clade A, suggesting that the Qiongzhou Strait served as a dispersal corridor during glaciation. Rising sea levels likely separated the Hainan population afterward. Ecological niche modeling showed that both populations have been viable since the last interglacial period, with demographic analyses indicating possible expansions during the Middle and Late Pleistocene, driven by favorable climates. This study highlights the significant effects of Pleistocene sea-level and climatic changes on the distribution and evolution of S. bifidus in China. [ABSTRACT FROM AUTHOR]

Melanastera sinica He & Burckhardt, sp. nov., a new psylloid species developing on Grewia sp., is described from Hainan, China. It is the first Melanastera species reported from Asia and China, and the second species from the Old World. While New World species of Melanastera are mostly associated with the plant families Melastomataceae and Annonaceae, the two Old World species develop on the malvaceous Grewia, a host otherwise used in psylloids by two Haplaphalara species. The new species is described, diagnosed and illustrated, and its host plant and biogeographic ranges are discussed. [ABSTRACT FROM AUTHOR]

The generic status of Microsandalus Stål, 1867 stat. rev. is discussed and formally revalidated. The type species of this genus, M. umbrosus Stål, 1867, is redescribed and illustrated with an emphasis on sexual dimorphism. The lectotype of M. umbrosus is designated. Pirates sobrius Walker, 1873 is found to be the brachypterous female of M. umbrosus, and therefore, a previous synonymy, which had recently gone unnoticed, is confirmed. A key to help separate peiratine genera distributed in Australia is provided. [ABSTRACT FROM AUTHOR]

Simple Summary: The reduviid genus Sycanus Amyot & Serville, 1843, possesses higher aesthetic value and plays a crucial role as a natural enemy in the control of agricultural and forestry pests. However, Sycanus from China has not undergone a comprehensive review for over four decades. Based on both molecular data and morphological evidence, we conducted a systematic review of the 14 Chinese Sycanus species, including a description of three new species. Due to the variability of body coloration and morphological similarity among closely related species, unresolved issues and debates still persist in the taxonomic study of the genus Sycanus from China. In this study, we conducted phylogenetic analyses and species delimitation for Sycanus in China based on a COI DNA barcoding dataset comprising 81 samples. The results revealed that all the samples could be classified into 12 species by integrating molecular analyses with morphological comparison. This paper provides a comprehensive systematic review of the Sycanus species found in China, including descriptions of three new species: S. taiwanensis Zhao & Cai sp. nov., S. flavicorius Li & Cai sp. nov., and S. hainanensis Wang & Cai sp. nov. Furthermore, it is proposed that S. croceovittatus Dohrn, 1859, S. leucomesus Walker, 1873, and S. villicus Stål, 1863, are three synonyms of S. bifidus (Fabricius, 1787); S. bicolor Hsiao, 1979, is a synonym of S. versicolor Dohrn, 1859; and S. hsiaoi Maldonado-Capriles, 1990, is a synonym of S. marginellus Putshkov, 1987. Additionally, brief biological information is provided for two species, S. falleni Stål, 1863, and S. croceus Hsiao, 1979. [ABSTRACT FROM AUTHOR]

Adenosine-to-inosine (A-to-I) RNA editing is the most prevalent RNA modification in the nervous systems of metazoans. To study the biological significance of RNA editing, we first have to accurately identify these editing events from the transcriptome. The genome-wide identification of RNA editing sites remains a challenging task. In this review, we will first introduce the occurrence, regulation, and importance of A-to-I RNA editing and then describe the established bioinformatic procedures and difficulties in the accurate identification of these sit esespecially in small sized non-model insects. In brief, (1) to obtain an accurate profile of RNA editing sites, a transcriptome coupled with the DNA resequencing of a matched sample is favorable; (2) the single-cell sequencing technique is ready to be applied to RNA editing studies, but there are a few limitations to overcome; (3) during mapping and variant calling steps, various issues, like mapping and base quality, soft-clipping, and the positions of mismatches on reads, should be carefully considered; (4) Sanger sequencing of both RNA and the matched DNA is the best verification of RNA editing sites, but other auxiliary evidence, like the nonsynonymous-to-synonymous ratio or the linkage information, is also helpful for judging the reliability of editing sites. We have systematically reviewed the understanding of the biological significance of RNA editing and summarized the methodology for identifying such editing events. We also raised several promising aspects and challenges in this field. With insightful perspectives on both scientific and technical issues, our review will benefit the researchers in the broader RNA editing community. [ABSTRACT FROM AUTHOR]

Simple Summary: The millipede assassin bugs are well known for their prey specialization. In this study, we examined the fine structures of the antennae, mouthparts, and legs of four genera and species of ectrichodiines using a scanning electronic microscope and compared them with those in Tribelocephalinae, a lineage closely related to Ectrichodiinae. We found that ectrichodiines possess distinctly more slightly transverse ridges on the mandibles, which probably facilitate stabilizing mandibular stylets in prey tissues. The small papillae on the legs are considered to adapt to immobilize millipedes. Overall, our study illustrates, at a microstructural level, the remarkable morphological adaption of prey manipulation in ectrichodiines, which will facilitate future studies on the adaptive evolution of feeding habits in Reduviidae. Species in Ectrichodiinae are known for their prey specialization on millipedes. However, knowledge of the morphological adaptations to this unique feeding habit was limited. In the current study, we examined the microstructures of the antennae, mouthparts, and legs of four millipede feeding ectrichodiines, Ectrychotes andreae (Thunberg, 1888), Haematoloecha limbata Miller, 1953, Labidocoris pectoralis (Stål, 1863), and Neozirta eidmanni (Taueber, 1930), and compared them with those of three species of tribelocephalines, a group closely related to Ectrichodiinae. On the antennae, we found four types of antennal sensilla. On the mouthparts, we recognized four types of labial sensilla. Sampled ectrichodiines have distinctly more and denser slightly transverse ridges on the external side of mandibles than tribelocephalines. E. andreae and H. limbata possess numerous small papillae fringed with densely arranged finger-print-like grains on the trochanter and femur; these probably facilitate the immobilization of prey. Overall, our study illustrates, at a microstructural level, the remarkable morphological adaption of prey manipulation in ectrichodiine, and has enhanced our understanding about stenophagy in the family Reduviidae. [ABSTRACT FROM AUTHOR]

Background: C-to-U RNA editing in plants is believed to confer its evolutionary adaptiveness by reversing unfavorable DNA mutations. This "restorative hypothesis" has not yet been tested genome-wide. In contrast, A-to-I RNA editing in insects like Drosophila and honeybee is already known to benefit the host by increasing proteomic diversity in a spatial-temporal manner (namely "diversifying hypothesis"). Methods: We profiled the RNA editomes of multiple tissues of Arabidopsis thaliana, Drosophila melanogaster, and Apis melifera. We unprecedentedly defined the haplotype diversity (HD) of RNA molecules based on nonsynonymous editing events (recoding sites). Results: Signals of adaptation is confirmed in Arabidopsis by observing higher frequencies and levels at nonsynonymous editing sites over synonymous sites. Compared to A-to-I recoding sites in Drosophila, the C-to-U recoding sites in Arabidopsis show significantly lower HD, presumably due to the stronger linkage between C-to-U events. Conclusions: C-to-U RNA editing in Arabidopsis is adaptive but it is not designed for diversifying the proteome like A-to-I editing in Drosophila. Instead, C-to-U recoding sites resemble DNA mutations. Our observation supports the restorative hypothesis of plant C-to-U editing which claims that editing is used for fixing unfavorable genomic sequences. [ABSTRACT FROM AUTHOR]

The recently reorganized classification of Mantodea has made significant progress in resolving past homoplasy problems, although some relationships among higher taxa remain uncertain. In the present study, we utilized newly sequenced mitogenomes and nuclear gene sequences of 23 mantid species, along with published data of 53 mantises, to perform familial-sampling structural comparisons of mantodean mitogenomes and phylogenomic studies. Our rstructural analysis revealed generally conserved mitogenome organizations, with a few cases of tRNA gene rearrangements, including the detection of trnL2 duplication for the first time. In our phylogenetic analysis, we found a high degree of compositional heterogeneity and lineage-specific evolutionary rates among mantodean mitogenomes, which frequently corresponded to several unexpected groupings in the topologies under site-homogeneous models. In contrast, the topologies obtained using the site-heterogeneous mixture model fit the currently accepted phylogeny of Mantodea better. Topology tests and four-cluster likelihood mapping analyses further determined the preferred topologies. Our phylogenetic results confirm the monophyly of superfamilial groups Schizomantodea, Amerimantodea, Heteromantodea, Promantidea, and Mantidea and recover the early-branching relationships as (Mantoidoidea + (Amerimantodea + (Metallyticoidea + Cernomantodea))). Additionally, the results suggest that the long-unresolved phylogenetic position of Majangidae should be placed within Mantidea, close to Mantoidea, rather than within Epaphroditoidea. Our findings contribute to understanding the compositional and structural diversity in mantodean mitogenomes, underscore the importance of evolutionary model selection in phylogenomic studies, and provide new insights into the high-level phylogeny of Mantodea. [ABSTRACT FROM AUTHOR]

Simple Summary: Triatominae, commonly known as kissing bugs, are blood-feeding insects that can carry the parasite Trypanosoma cruzi to spread Chagas disease. In this study, we conducted a taxonomic review of Chinese triatomines, which involved describing two new species, Triatoma picta Zhao & Cai sp. nov. and T. atrata Zhao & Cai sp. nov. We also calculated the pairwise genetic distances of Triatoma and offered a key to species of Triatominae in China. This review may facilitate a better understanding of the diversity of Chinese kissing bugs. Triatominae, the only blood-sucking subfamily in Reduviidae, are the vectors of Chagas disease. The majority of them are distributed in the Americas, while the diversity in China has been underestimated, as only two species have been recorded. Here, we describe two new species from China, Triatoma picta Zhao & Cai sp. nov. and T. atrata Zhao & Cai sp. nov., and provide a redescription of T. sinica Hsiao, 1965, along with remarks on T. rubrofasciata (De Geer, 1773). To facilitate the identification, we include photos, especially of genitalia, as well as a distribution map and a key to Chinese triatomines. We calculated the pairwise genetic distances between 23 Triatoma species, which further supported the validity of these new species. We anticipate that our taxonomic review will be useful for identifying Chinese Triatominae. [ABSTRACT FROM AUTHOR]

Simple Summary: Cacopsylla, the most species-rich genus of Psyllidae, has around 500 known species worldwide. These insects are known for being host-specific, and some of them are regarded as important pests. Here, we described a new species, Cacopsylla fuscicella sp. nov., which develops on loquats. In addition, we sequenced its mitochondrial genome and used these data to construct a phylogenetic tree of Psyllidae, while also calculating the interspecific genetic distances. Using integrative taxonomy methods, we confirmed that the new species, Cacopsylla fuscicella sp. nov., should be grouped within genus Cacopsylla. Psylloidea, commonly known as jumping plant-lice, have a phloem-sucking habit and strong specificity to their host plants. Within the Psyllidae family, the genus Cacopsylla Ossiannilsson, 1970 stands out as being the most diverse, with three species feeding on the genus Eriobotrya Lindl. In this study, a new psyllid species, Cacopsylla fuscicella sp. nov., was described from China. It is a pest of Eriobotrya japonica (Thunb.) Lindl. and has been cultivated as a commercial fruit tree for years. Illustrations of habitus, morphological structures, and its damage to loquat were also provided. The complete mitochondrial genome of C. fuscicella sp. nov. was sequenced and annotated. The phylogenetic tree inferred from the maximum likelihood analyses confirmed C. fuscicella sp. nov. as a member of the genus Cacopsylla. Genetic distances were generated to assess comparative genetic distances within Psyllinae. [ABSTRACT FROM AUTHOR]

Insect speciation is among the most fascinating topics in evolutionary biology; however, its underlying mechanisms remain unclear. Allopatric speciation represents one of the major types of speciation and is believed to have frequently occurred during glaciation periods, when climatic oscillation may have caused suitable habitats to be fragmented repeatedly, creating geographical isolation among populations. However, supporting evidence for allopatric speciation of insects in East Asia during the Pleistocene glaciation remains lacking. We aim to investigate the effect of climatic oscillation during the Pleistocene glaciation on the diversification pattern and evolutionary history of hemipteran insects and to test the hypothesis of Pleistocene species stability using spinous assassin bugs Sclomina (Hemiptera: Reduviidae), a small genus widely distributed in southern China but was later found to have cryptic species diversity. Here, using the whole mitochondrial genome (mitogenome) and nuclear ribosomal RNA genes, we investigated both interspecific and intraspecific diversification patterns of spinous assassin bugs. Approximate Bayesian computation, ecological niche modeling, and demographic history analyses were also applied to understand the diversification process and driven factors. Our data suggest that the five species of Sclomina are highly diverged, despite three of them currently being cryptic. Speciation occurred during the Pleistocene when suitable distribution areas were possibly fragmented. Six phylogeographic groups in the type species S. erinacea were identified, among which two groups underwent expansion during the early Last Glacial Period and after Last Glacier Maximum. Our analyses suggest that this genus may have experienced climate‐driven habitat fragmentation and postglacial expansion in the Pleistocene, promoting allopatric speciation and intraspecific diversification. Our results reveal underestimated species diversity in a small insect group and illustrate a remarkable example of allopatric speciation of insects in East Asia promoted by Pleistocene climatic oscillations. These findings provide important insights into the speciation processes and aid the conservation of insect species diversity. [ABSTRACT FROM AUTHOR]

Simple Summary: Antennae and mouthparts are key organs for food searching and feeding in insects. In the present study, the microstructures of the antennae and mouthparts of the flat bugs Mezira yunnana Hsiao were demonstrated. Five types of antennal sensilla and three types of labial sensilla were documented. Labial tip gustatory sensilla form a small group of only three pairs, which is essentially different in this species from other true bugs. The labial tip is constricted distally, which is rarely observed in other pentatomomorphans. Teeth on the external surface of the mandibular apex are ridge-like and uniform. These characteristics may be associated with the species' unique fungi-feeding habit. Many species of the family Aradidae (also known as flat bugs) feed on fungal mycelia and fruiting bodies. In order to better understand the morphological adaptation to this unique feeding habit, we examined the microstructure of antennae and mouthparts of an aradid species, Mezira yunnana Hsiao, using scanning electron microscope, and documented the fungal feeding process under laboratory conditions. The antennal sensilla include three subtypes of sensilla trichodea, three subtypes of sensilla basiconica, two subtypes of sensilla chaetica, sensilla campaniformia, and sensilla styloconica. The apex of the second segment of flagellum has a large number of various sensilla forming a sensilla cluster. The labial tip is distally constricted, which is rarely observed in other Pentatomomorpha species. The labial sensilla include three subtypes of sensilla trichodea, three subtypes of sensilla basiconica, and a sensilla campaniformia. The tip of the labium has only three pairs of sensilla basiconica III and small comb-shaped cuticular processes. The external surface of the mandibular apex has 8–10 ridge-like central teeth. A series of key morphological structures associated with mycetophagous feeding habit were identified, which will facilitate future studies on adaptive evolution of species in Pentatomomorpha as well as in other heteropteran lineages. [ABSTRACT FROM AUTHOR]

Here, we reconstructed the Hemiptera phylogeny based on the expanded mitochondrial protein-coding genes and the nuclear18S rRNAgene, separately. The differential rates of change across lineages may associate with long-branch attraction (LBA) effect and result in conflicting estimates of phylogeny from different types of data. To reduce the potential effects of systematic biases on inferences of topology, various data coding schemes, site removal method, and different algorithms were utilized in phylogenetic reconstruction. We show that the outgroups Phthiraptera, Thysanoptera, and the ingroup Sternorrhyncha share similar base composition, and exhibit “long branches” relative to other hemipterans. Thus, the long-branch attraction between these groups is suspected to cause the failure of recovering Hemiptera under the homogeneous model. In contrast, a monophyletic Hemiptera is supported when heterogeneous model is utilized in the analysis. Although higher level phylogenetic relationships within Hemiptera remain to be answered, consensus between analyses is beginning to converge on a stable phylogeny. [ABSTRACT FROM AUTHOR]

Coridius chinensis (Hemiptera: Dinidoridae) is a medicinal insect. Its mitochondrial gene arrangement is consistent with that of Drosophila melanogaster and Erthesina fullo, the two insects with well-studied mitochondrial transcription. To investigate whether the structural consistency of mitochondrial genes leads to similarities in transcription and post-transcriptional processing, we improved the gene annotation and constructed a quantitative transcription map for the C. chinensis mitochondrial genome (mitogenome) using full-length transcriptome sequencing. The size of this mitogenome was 16,214 bp and the proposed model of mitochondrial transcription was similar to that of Drosophila. Both strands were nearly entirely transcribed except for the antisense genes downstream of trnS2 on N strand. The expression of cytochrome c subunit genes is higher than that of NADH-dehydrogenase subunit genes. The post-transcriptional cleavage process followed the "tRNA punctuation" model, and both the "reverse cleavage" model in Drosophila and "forward cleavage" model in E. fullo were found in C. chinensis. In addition, we found that long non-coding RNAs from the control region contained tandem repeats. Polyadenylation was performed after CCA triplet at the 3′ end of tRNA. The isoform diversity of lrRNA was identified. Our study sheds light on the transcriptional regulation and RNA processing of insect mitogenomes with the putative ancestral gene arrangement. [ABSTRACT FROM AUTHOR]

The ChineseCacopsyllaspecies associated with Spiraea are revised. Three new species (Cacopsylla falcatasp. nov.,C. nocturnasp. nov. andC. qilianensissp. nov.) are described, and two [C. hyalinonemaeLi and Yang, 1989 andC. spiraeicola(Li, 2011) comb. nov.] are redescribed. A new combination is also proposed forCacopsylla tetrotaenialis(Li and Yang, 1989) comb. nov. Among the five species,C. falcataandC. qilianensisare affirmed to develop onSpiraea, as fifth instar immatures were found. The host plants of the other species remain uncertain. Based on morphological grounds, it is suggested thatC. falcataandC. nocturnaare closely related, but that the five species associated withSpiraeado not constitute a monophyletic group. [ABSTRACT FROM AUTHOR]

Simple Summary: There is a wide variety of insects in the suborder Heteroptera (true bugs), with various feeding habits and living habitats. Microbes that live inside insect guts play critical roles in aspects of host nutrition, physiology, and behavior. However, most studies have focused on herbivorous stink bugs of the infraorder Pentatomomorpha and the gut microbiota associated with the megadiverse heteropteran lineages, and the implications of ecological and diet variance have been less studied. Here, we investigated the gut microbial biodiversity of 30 species of true bugs representative of different ecological niches and diets. Proteobacteria and Firmicutes dominated all samples. True bugs that live in aquatic environments had a variety of bacterial taxa that were not present in their terrestrial counterparts. Carnivorous true bugs had distinct gut microbiomes compared to herbivorous species. In particular, assassin bugs of the family Reduviidae had a characteristic gut microbiota consisting mainly of Enterococcus and different species of Proteobacteria, implying a specific association between the gut bacteria and the host. These findings reveal that the environmental habitats and diets synergistically contributed to the diversity of the gut bacterial community of true bugs. Insects are generally associated with gut bacterial communities that benefit the hosts with respect to diet digestion, limiting resource supplementation, pathogen defense, and ecological niche expansion. Heteroptera (true bugs) represent one of the largest and most diverse insect lineages and comprise species consuming different diets and inhabiting various ecological niches, even including underwater. However, the bacterial symbiotic associations have been characterized for those basically restricted to herbivorous stink bugs of the infraorder Pentatomomorpha. The gut microbiota associated with the megadiverse heteropteran lineages and the implications of ecological and diet variance remain largely unknown. Here, we conducted a bacterial 16S rRNA amplicon sequencing of the gut microbiota across 30 species of true bugs representative of different ecological niches and diets. It was revealed that Proteobacteria and Firmicute were the predominant bacterial phyla. Environmental habitats and diets synergistically contributed to the diversity of the gut bacterial community of true bugs. True bugs living in aquatic environments harbored multiple bacterial taxa that were not present in their terrestrial counterparts. Carnivorous true bugs possessed distinct gut microbiota compared to phytophagous species. Particularly, assassin bugs of the family Reduviidae possessed a characterized gut microbiota predominantly composed of one Enterococcus with different Proteobacteria, implying a specific association between the gut bacteria and host. Overall, our findings highlight the importance of the comprehensive surveillance of gut microbiota association with true bugs for understanding the molecular mechanisms underpinning insect–bacteria symbiosis. [ABSTRACT FROM AUTHOR]

Simple Summary: Aeolothrips, commonly known as banded thrips, is the largest genus of the family Aeolothripidae (predatory thrips). In the current study, we sequenced the mitochondrial genome (mitogenome) of the banded thrip species Aeolothrips xinjiangensis. We found a novel gene arrangement in this mitogenome that has not been reported in Thysanoptera. By comparing the gene order and rearrangement patterns, we found seven identical gene blocks and three identical rearrangement events in two mitogenomes of banded thrips. There was marked variation in the mitochondrial gene order across thrip species, with only two conserved gene blocks shared by all 14 thrips. In addition, we found a positive correlation between the degree of gene rearrangement and evolutionary rate. Our results suggested that the mitogenomes of thrips have tended to be stable since their massive rearrangement. Extensive gene rearrangement is characteristic in the mitogenomes of thrips (Thysanoptera), but the historical process giving rise to the contemporary gene rearrangement pattern remains unclear. To better understand the evolutionary processes of gene rearrangement in the mitogenomes of thrips, we sequenced the mitogenome of the banded thrip species Aeolothrips xinjiangensis. First, we found a novel mitochondrial gene order in this species. This mitogenome is 16,947 bp in length and encodes the typical 37 coding genes (13 protein-coding genes, 22 tRNA genes, and two rRNA genes) of insects. The gene arrangement was dramatically different from the putative ancestral mitogenome, with 26 genes being translocated, eight of which were inverted. Moreover, we found a novel, conserved gene block, trnC-trnY, which has not been previously reported in the mitogenomes of thrips. With this newly assembled mitogenome, we compared mitogenome sequences across Thysanoptera to assess the evolutionary processes giving rise to the current gene rearrangement pattern in thrips. Seven identical gene blocks were shared by two sequenced banded thrip mitogenomes, while the reversal of ND2 combined with TDRL events resulted in the different gene orders of these two species. In phylogenetic analysis, the monophyly of the suborders and families of Thysanoptera was well supported. Across the gene orders of 14 thrips, only two conserved gene blocks, ATP8-ATP6 and ND4-ND4L, could be found. Correlation analysis showed that the degree of gene rearrangement was positively correlated with the non-synonymous substitution rate in thrips. Our study suggests that the mitogenomes of thrips remain stable over long evolutionary timescales after massive rearrangement during early diversification. [ABSTRACT FROM AUTHOR]

Simple Summary: Assassin bugs are one of the diversified groups of venomous predatory insects. Their venom is secreted from three different lumens of the salivary gland and can lead to paralysis, lethality, and liquidation of the prey, respectively. Nevertheless, most reduviid venom components responsible for these effects are not clear. In this study, we use transcriptomics and proteomics to determine the effective salivary protein components in the separate lumen of salivary gland from twin-spotted assassin bug Platymeris biguttatus and to conduct toxicological analysis on the function of the salivary gland compartments. Our study sheds light on the functional cooperation between different salivary gland lumens of assassin bugs and will further the understanding of physiological adaptations of venom-based predation and defense in venomous hemipterans. Assassin bugs use their salivary venoms for various purposes, including defense, prey paralyzation, and extra-oral digestion, but the mechanisms underlying the functional complexity of the venom remain largely unclear. Since venom glands are composed of several chambers, it is suggested that individual chambers may be specialized to produce chemically distinct venoms to exert different functions. The current study assesses this hypothesis by performing toxicity assays and transcriptomic and proteomic analysis on components from three major venom gland chambers including the anterior main gland (AMG), the posterior main gland (PMG), and the accessory gland (AG) of the assassin bug Platymeris biguttatus. Proteotranscriptomic analysis reveals that AMG and PMG extracts are rich in hemolytic proteins and serine proteases, respectively, whereas transferrin and apolipophorin are dominant in the AG. Toxicity assays reveal that secretions from different gland chambers have distinct effects on the prey, with that from AG compromising prey mobility, that from PMG causing prey death and liquifying the corpse, and that from AMG showing no significant physiological effects. Our study reveals a functional cooperation among venom gland chambers of assassin bugs and provides new insights into physiological adaptations to venom-based predation and defense in venomous predatory bugs. [ABSTRACT FROM AUTHOR]

Animal mitochondrial (mt) genomes are typically double-strand circular DNA molecules, but diverse structural variations have been widely found in multiple groups. In parasitic lice (Phthiraptera), the structure of mt genomes varies remarkably across all five suborders. In this study, we reported the complete mt genome of a chicken body louse, Menacanthus cornutus, which has a typical single circular mt chromosome and drastic mt gene rearrangements. This mt genome is 15,693 bp in length, consisting of 13 protein-coding genes, 23 tRNA genes, 2 rRNA genes, and a control region. A comparison with a typical insect mt genome suggested that two highly similar trnM are present in the mt genome of M. cornutus. Moreover, almost every single gene was rearranged, and over half of mt genes were inverted. Phylogenetic analyses inferred from the mt genome sequences supported the monophyly and position of Amblycera. Mapped over the phylogenetic relationships of Amblycera, we identified two inversion events for the conserved gene blocks in Boopidae and Menoponidae. The inverted ND4L-ND4 was likely a synapomorphic rearrangement in Menoponidae. Our study demonstrated the importance of sequencing mt genomes for additional taxa to uncover the mechanism underlying the structural evolution of the mt genome in parasitic lice. [ABSTRACT FROM AUTHOR]

Biological invasion has been a serious global threat due to increasing international trade and population movements. Tracking the source and route of invasive species and evaluating the genetic differences in their native regions have great significance for the effective monitoring and management, and further resolving the invasive mechanism. The spotted lanternfly Lycorma delicatula is native to China and invaded South Korea, Japan, and the United States during the last decade, causing severe damages to the fruits and timber industries. However, its global phylogeographic pattern and invasion history are not clearly understood. We applied high‐throughput sequencing to obtain 392 whole mitochondrial genome sequences from four countries to ascertain the origin, dispersal, and invasion history of the spotted lanternfly. Phylogenomic analyses revealed that the spotted lanternfly originated from southwestern China, diverged into six phylogeographic lineages, and experienced northward expansion across the Yangtze River in the late Pleistocene. South Korea populations were derived from multiple invasions from eastern China and Japan with two different genetic sources of northwestern (Loess Plateau) and eastern (East Plain) lineages in China, whereas the each of Japan and the United States had only one. The United States populations originated through single invasive event from South Korea, which served as a bridgehead of invasion. The environmental conditions, especially the distribution of host Ailanthus trees, and adaptability possibly account for the rapid spread of the spotted lanternfly in the native and introduced regions. [ABSTRACT FROM AUTHOR]

Aphidius gifuensis is a parasitoid wasp that has been commercially bred and released in large scale as a biocontrol agent for the management of aphid pests. As a highly efficient endoparasitoid, it is also an important model for exploring mechanisms of parasitism. Currently, artificially bred populations of this wasp are facing rapid decline with undetermined cause, and mechanisms underlying its parasitoid strategy remain poorly understood. Exploring the mechanism behind its population decline and the host–parasitoid relationship is impeded partly due to the lack of a comprehensive genome data for this species. In this study, we constructed a high‐quality reference genome of A. gifuensis using Oxford Nanopore sequencing and Hi‐C (proximity ligation chromatin conformation capture) technology. The final genomic assembly was 156.9 Mb, with a contig N50 length of 3.93 Mb, the longest contig length of 10.4 Mb and 28.89% repetitive sequences. 99.8% of genome sequences were anchored onto six linkage groups. A total of 11,535 genes were predicted, of which 90.53% were functionally annotated. Benchmarking Universal Single‐Copy Orthologs (BUSCO) analysis showed the completeness of assembled genome is 98.3%. We found significantly expanded gene families involved in metabolic processes, transmembrane transport, cell signal communication and oxidoreductase activity, in particular ATP‐binding cassette (ABC) transporter, Cytochrome P450 and venom proteins. The olfactory receptors (ORs) showed significant contraction, which may be associated with the decrease in host recognition. Our study provides a solid foundation for future studies on the molecular mechanisms of population decline as well as host–parasitoid relationship for parasitoid wasps. [ABSTRACT FROM AUTHOR]

Pachynomidae is a poorly known heteropteran group currently considered as a distinct family closely related to Reduviidae. Taxonomic position of Pachynomidae has been debated for a long time. Knowledge about mitochondrial genome (mitogenome) of this family also remain limited. In the present study, we describe the complete mitogenome of Camarochiloides weiweii , the first mitogenome sequenced for this family. This mitogenome consists of 13 protein-coding genes, two rRNA genes and 21 tRNA genes. Two tRNA gene rearrangements in this genome, including the translocation of trnA and trnR as well as the transposition of trnH , were observed and could be explained by the tandem duplication-random loss (TDRL) model. Bayesian and maximum likelihood analyses based on sequences of three different mitogenomic datasets recovered the monophyly of Reduvioidea, and the sister relationship between Reduvioidea and the remaining Cimicomorpha lineages. This study enlightens the future application of mitogenomic data in the phylogenetic study of Cimicomorpha based on the large-scale sampling. [ABSTRACT FROM AUTHOR]

Gene rearrangements in the mitochondrial genome (mt genome) are common in certain insect groups and can be an informative character for phylogenetic reconstruction. However, knowledge of the mechanism and biases of gene rearrangement in insect mt genomes is still limited. With an accelerated rate of gene rearrangements, Hymenoptera is an important group for mt genome rearrangements diversity and for understanding the gene rearrangement evolution in mt genomes. Here, we sequenced the complete mt genome of Aphidius gifuensis and analyzed the evolution of tRNA gene rearrangements in the mt genomes of ichneumonoid wasps. Two control regions were detected in A. gifuensis and most of the tRNA rearrangement events occurred around these control regions. tRNA gene rearrangements occurred in almost all of the sequenced mt genomes of Ichneumonoidea and the gene block CR - trnI - trnQ - trnM - ND2 - trnW - trnC - trnY was the main hot spot of gene rearrangement. Mapped over the backbone phylogeny of Ichneumonoidea, we found that the inversion and translocation of both trnI and trnM is likely a synapomorphic rearrangement in Braconidae. Our study also demonstrated that the gene block CR - trnI - trnQ - trnM - ND2 - trnW - trnC - trnY was important for inferring the gene rearrangement dynamics in Ichneumonoidea. [ABSTRACT FROM AUTHOR]

Western flower thrips (WFTs), Frankliniella occidentalis Pergrande, and onion thrips (OTs), Thrips tabaci Lindeman, are two cosmopolitan insect pests of agricultural and horticultural plants. Understanding the occurrence and development of thrips on plants is crucial for identifying suitable plants that can be used for developing a "push‐pull" strategy against thrips. In this study, the dynamics of WFTs and OTs on plants (Allium fistulosum L., Medicago sativa L., Luffa cylindrica (L.) Roem., Ocimum basilicum L., and Schizonepeta tenuifolia (Benth.) Briq.) were investigated for two consecutive years (2018–2019). Throughout the survey, the abundances of both thrips species were strongly associated with plant species and plant phenology; both thrips species were present at relatively high densities on M. sativa but very low densities on O. basilicum and S. tenuifolia. Populations of both thrips species greatly increased during plant flowering. A Y‐tube olfactory test was used to study the effects of plant volatiles in mediating thrips behaviour and showed that volatiles of M. sativa were attractive to both thrips species whether emitted by the plant in the vegetative or flowering stage, while volatiles of O. basilicum and S. tenuifolia were repellent to thrips. Additionally, because of the presence of a high number of floral chemicals, both thrips species exhibited a greater preference for volatiles emitted by plants in the flowering period over those emitted by plants in the vegetative period. Our observations indicate that plant species and flowering status play an important role in the abundance dynamics of thrips and that the volatiles of flowering plants attract thrips more strongly than volatiles emitted by vegetative plants. These findings can facilitate the screening of attractive/unattractive plants for developing push‐pull strategies to control thrips. [ABSTRACT FROM AUTHOR]

Species in Hymenoptera usually show exceptionally high rates of mitochondrial molecular evolution and dramatic gene rearrangements, which has been attributed to their parasitic lifestyle. However, mitochondrial genome (mitogenome) of chalcidoid wasps is still poorly understood and the evolution of gene rearrangements is still unclear. In this study, the nearly complete mitogenome of Pachyneuron aphidis , a chalcidoid wasp mainly hyperparasitizes the Aphidius gifuensis , was sequenced using a next-generation sequencing strategy. This genome is 15,137 bp in length, including 13 PCGs, 22 tRNAs, two rRNAs and a partial control region. Alignment with other Chalcidoidea mitogenomes revealed a novel inversion in the srRNA - trnV gene cluster in P. aphidis , which is the first of its kind to be reported in Chalcidoidea. Breakpoint distances analysis showed the high value of chalcidoid wasps compare to the ancestral arrangement pattern, which reflected as extensive gene rearrangements. Despite the high frequency of gene rearrangements in these insects, analyses of gene rearrangement and phylogenetic trees showed that species from the same family and the genus tent to have similar gene orders, and the conserved gene blocks (ND3-trnG , srRNA - trnV and COIII - ATP6 - ATP8 - trnD - trnK - COII - trnL2 - COI) can usually be identified, especially at the family level of chalcidoid wasps. [ABSTRACT FROM AUTHOR]

The higher‐level phylogeny of Pentatomomorpha, the second largest infraorder of true bugs (Hemiptera: Heteroptera), which includes many important agriculture and forestry pests, has been debated for decades. To investigate the phylogeny and evolutionary history of Pentatomomorpha, we assembled new mitochondrial genomes for 46 species through next‐generation sequencing of pooled genomic DNA. Based on a much broader taxon sampling than available previously, Bayesian analyses using a site‐heterogeneous mixture model (CAT+GTR) resolved the higher‐level phylogeny of Pentatomomorpha as (Aradoidea + (Pentatomoidea + (Coreoidea + (Lygaeoidea + Pyrrhocoroidea)))). There was a transition from trnT/trnP to trnP/trnT in the common ancestor of Pyrrhocoroidea, which indicates that this gene rearrangement could be an autapomorphy for Pyrrhocoroidea. Divergence time analyses estimated that Pentatomomorpha originated c. 242 Ma in the Middle Triassic, and most of the recognized superfamilies originated during the Middle Jurassic to Early Cretaceous. The diversification of families within Pentatomomorpha largely coincided with the radiation of angiosperms during the Early Cretaceous. [ABSTRACT FROM AUTHOR]

Insect mitochondrial genomes (mitogenome) generally present a typical gene order, which is considered as the ancestral arrangement. All sequenced mitogenomes in the Thysanoptera display high levels of gene rearrangement. Due to limited number of thrips mitogenomes sequenced, how gene rearrangement may be shaped by evolution remain unclear. Here, we analyzed 33 thrips mitogenomes, including 14 newly sequenced. These mitogenomes were diverse in organization, nucleotides substitution and gene arrangements. We found 28 highly rearranged gene orders with the breakpoints of gene rearrangements from 25 to 33. Reconstruction of the ancestors mitochondrial gene arrangements states indicated that Tubulifera have more complex pathways than Terebrantia in the gene order evolution. Molecular calibration estimated that divergence of two suborders occurred in the middle Triassic while the radiation of thrips was associated with the arose and flourish of angiosperm. Our evolutionary hypothesis testing suggests that relaxation of selection pressure enabled the early phase of Thysanoptera evolution, followed by a stronger selective pressure fixed diversification. Our analyses found gene inversion increases the nonsynonymous substitution rates and provide an evolutionary hypothesis driving the diverse gene orders. • Mitogenomic characteristics in different thrips families and suborders were summarized. • The evolution of new gene order is associated with adaptive selection. • Gene inversion may promote nonsynonymous mutation rate of mitochondrial genes in insects. [ABSTRACT FROM AUTHOR]

Insect mitochondrial genomes (mitogenome) generally present a typical gene order, which is considered as the ancestral arrangement. All sequenced mitogenomes in the Thysanoptera display high levels of gene rearrangement. Due to limited number of thrips mitogenomes sequenced, how gene rearrangement may be shaped by evolution remain unclear. Here, we analyzed 33 thrips mitogenomes, including 14 newly sequenced. These mitogenomes were diverse in organization, nucleotides substitution and gene arrangements. We found 28 highly rearranged gene orders with the breakpoints of gene rearrangements from 25 to 33. Reconstruction of the ancestors mitochondrial gene arrangements states indicated that Tubulifera have more complex pathways than Terebrantia in the gene order evolution. Molecular calibration estimated that divergence of two suborders occurred in the middle Triassic while the radiation of thrips was associated with the arose and flourish of angiosperm. Our evolutionary hypothesis testing suggests that relaxation of selection pressure enabled the early phase of Thysanoptera evolution, followed by a stronger selective pressure fixed diversification. Our analyses found gene inversion increases the nonsynonymous substitution rates and provide an evolutionary hypothesis driving the diverse gene orders. • Mitogenomic characteristics in different thrips families and suborders were summarized. • The evolution of new gene order is associated with adaptive selection. • Gene inversion may promote nonsynonymous mutation rate of mitochondrial genes in insects. [ABSTRACT FROM AUTHOR]

The reduviid subfamily Triatominae, also called kissing bugs, are vectors of Chagas disease, which is one of the most seriously neglected tropical parasitic diseases. Only three complete mitochondrial genomes of kissing bugs from the genus Triatoma have been sequenced to date. To better understand the diversity of mitochondrial genomes and the evolution of kissing bugs, mitochondrial genomes of three kissing bugs, Triatoma migrans , Panstrongylus rufotuberculatus , and Rhodnius pictipes , were sequenced using next-generation sequencing and a comparative mitochondrial genomic analysis of three genera and two tribes in Triatominae was conducted. Kissing bug mitochondrial genomes shared a similar pattern of nucleotide composition, gene order, and structure of control region. The comparison among orthologous protein-coding genes indicated that different genes had different rates of molecular evolution and six genes (ND1 , ND2 , ND4L , ND5 , ND6 , and ATP8) had higher evolutionary rates than other protein-coding genes. Phylogenetic analyses inferred from mitochondrial genome sequences supported a sister relationship between Triatominae and Stenopodainae, and the genus Triatoma was paraphyletic. The present study revealed the high conservation of the mitochondrial genome organization of kissing bugs and highlighted the utility of mitochondrial genomes in the phylogenetic study of Triatominae. [ABSTRACT FROM AUTHOR]

Booklice in the genus Liposcelis (Psocodea: Liposcelididae) are essential storage pests worldwide. Fragmented mt genomes have been identified in the Liposcelis species together with the typical mitochondrial (mt) genome, which is a single circular chromosome with 37 genes. Gene rearrangement, pseudogenes, and repeat regions (RRs) are very common among fragmented mt genomes. We sequenced the mt genome of the booklouse L. brunnea , the type species of the genus Liposcelis. We identified 37 genes in the mt genome of L. brunnea , which was fragmented into three chromosomes. The chromosomes I, II, III were 7.3 kb, 5.5 kb, and 5.3 kb in size with 9, 19, and 15 genes, respectively. In addition, 16 pseudogenes and four repeat regions were present in three chromosomes. Gene rearrangement in the mt genome of L. brunnea was obvious compared to that in other mt genomes in the genus Liposcelis. We found a possible correlation among mt genome rearrangement, the morphological classification standard, and phylogenetic relationships. In summary, a three-chromosome mt genome in an insect was identified for the first time, which may aid in understanding mt genome fragmentation, gene rearrangement, and evolution. [ABSTRACT FROM AUTHOR]

Abstract Reduviidae is the second largest family of Heteroptera and most of them are important natural enemies of agricultural and forest pests. Most of the sequenced mitochondrial (mt) genomes in this family have the typical gene arrangement of insects and encode 37 coding genes (13 protein-coding genes, 22 tRNA genes and two rRNA genes). In the present study, we sequenced the mt genome of Phalantus geniculatus from the subfamily Peiratinae through high-throughput sequencing and encountered the duplication of tRNA genes for the first time in this subfamily. We identified 23 tRNA genes, including 22 tRNAs commonly found in insect mt genomes and an extra trnT (trnT2), which has high sequence similarity (96.9%) to trnT1. The presence of a " pseudo - trnP " in the non-coding region between trnT1 and trnT2 supports the hypothesis that the presence of an extra trnT can be explained by the tandem duplication-random loss (TDRL) model. Phylogenetic results inferred from mt genome sequences supported a sister relationship between Phymatinae and the remaining sampled subfamilies, as well as a paraphyletic Reduviinae. The present study highlights the utility of mt genomes in the phylogenetic study of Reduviidae based on the large scale taxon sampling in the future. [ABSTRACT FROM AUTHOR]

Organelle genome fragmentation has been found in a wide range of eukaryotic lineages; however, its use in phylogenetic reconstruction has not been demonstrated. We explored the use of mitochondrial (mt) genome fragmentation in resolving the controversial suborder-level phylogeny of parasitic lice (order Phthiraptera). There are approximately 5000 species of parasitic lice in four suborders (Amblycera, Ischnocera, Rhynchophthirina, and Anoplura), which infest mammals and birds. The phylogenetic relationships among these suborders are unresolved despite decades of studies. We sequenced the mt genomes of eight species of parasitic lice and compared them with 17 other species of parasitic lice sequenced previously. We found that the typical single-chromosome mt genome is retained in the lice of birds but fragmented into many minichromosomes in the lice of eutherian mammals. The shared derived feature of mt genome fragmentation unites the eutherian mammal lice of Ischnocera (family Trichodectidae) with Anoplura and Rhynchophthirina to the exclusion of the bird lice of Ischnocera (family Philopteridae). The novel clade, namely Mitodivisia, is also supported by phylogenetic analysis of mt genome and cox1 gene sequences. Our results demonstrate, for the first time, that organelle genome fragmentation is informative for resolving controversial high-level phylogenies. [ABSTRACT FROM AUTHOR]

A large-sized assassin bug Agriosphodrus dohrni (Signoret), has been recorded from India, Vietnam, China and Japan. It is one of the potential biological control agents against some important agricultural and forest pests. This species is speculated to have invaded Japan from its native range in China about 60 years ago. We used three mitochondrial gene fragments ( COI , Cytb , and ND5 ) and one nuclear gene fragment ( EF-1α ) to clarify the invasion history of A. dohrni and assess the effects of geographic events and associated ecological adaptation on the distribution pattern. The native populations of A. dohrni in China are divided into three distinct groups, which might be molded by the Early Pleistocene glaciation event and diverged during the Calabrian Stage. However, consistent with the hypothesis of a recent invasion, extremely low level of genetic variation was detected in the Japanese populations, with only two haplotypes for the combined mitochondrial genes. Both the splits network and the ML/BI phylogenetic trees revealed that haplotypes of Japan were more closely-related to those from eastern China. Therefore, we postulate that there has been only one introduction event, probably from somewhere around the Nanjing (NJ) and Lin'an (LA) populations of eastern China. [ABSTRACT FROM AUTHOR]

The mitochondrial genome of an assassin bug,Oncocephalus breviscutumReuter, is a typical circular DNA molecule of 15,984 bp with 37 genes and a large control region. The gene order is identical to that of the putative ancestral arrangement of insects. Twelve protein-coding genes start with ATN codon andND4Luses GTG. All of the 22 tRNAs, ranging from 61 to 70 bp, have the clover-leaf structure except for the dihydrouridine (DHU) arm oftrnS2forms a simple loop. The control region is 1345 bp in length and includes six tandem repeats of three 31-nt and three 145-nt units. [ABSTRACT FROM PUBLISHER]

Mitochondrial phylogenomics is often controversial, in particular for inferring deep relationships. The recent rapid increase of mitochondrial genome data provides opportunities for better phylogenetic estimates and assessment of potential biases resulting from heterogeneity in nucleotide composition and mutation rates. Here, we gathered 76 mitochondrial genome sequences for Heteroptera representing all seven infraorders, including 17 newly sequenced mitochondrial genomes. We found strong heterogeneity in base composition and contrasting evolutionary rates among heteropteran mitochondrial genomes, which affected analyses with various datasets and partitioning schemes under site-homogeneous models and produced false groupings of unrelated taxa exhibiting similar base composition and accelerated evolutionary rates. Bayesian analyses using a site-heterogeneous mixture CAT+GTR model showed high congruence of topologies with the currently accepted phylogeny of Heteroptera. The results confirm the monophyly of the six infraorders within Heteroptera, except for Cimicomorpha which was recovered as two paraphyletic clades. The monophyly of Terheteroptera (Cimicomorpha and Pentatomomorpha) and Panheteroptera (Nepomorpha, Leptopodomorpha and Terheteroptera) was recovered demonstrating a significant improvement over previous studies using mitochondrial genome data. Our study shows the power of the site-heterogeneous mixture models for resolving phylogenetic relationships with Heteroptera and provides one more case showing that model adequacy is critical for accurate tree reconstruction in mitochondrial phylogenomics. [ABSTRACT FROM AUTHOR]

The control region (CR) of the mitochondrial genome (mitogenome) represents a major noncoding fragment with several special structural features that are thought to be responsible for the initiation of mitogenome transcription and replication. However, few studies have revealed the evolutionary patterns of CR in the phylogenetic context. Here, we explain the characteristics and evolution of CR in Tortricidae, inferred from a mitogenome-based phylogeny. The first complete mitogenomes of the genera Meiligma and Matsumuraeses were sequenced. Both mitogenomes are double-stranded circular DNA molecules with lengths of 15,675 bp and 15,330 bp, respectively. Phylogenetic analyses derived from 13 protein-coding genes and two ribosomal RNAs showed that most tribes, including subfamilies Olethreutinae and Tortricinae, were recovered as monophyletic clades, similar to previous studies based on morphological or nuclear data. Moreover, comprehensive comparative analyses of the structural organization and role of tandem replications on the length variation and high AT content of CR sequences were conducted. The results reveal a significant positive correlation between the total length and AT content of tandem repeats and whole CR sequences in Tortricidae. The structural organization in CR sequences is diverse, even between closely related tribes, which demonstrates the plasticity of the mitochondrial DNA molecule in Tortricidae. • Phylogenetic relationship of Tortricidae was explored through all available mitogenomes. • The structural organization and role of tandem replications on the length variation and AT content of control region sequences were investigated. [ABSTRACT FROM AUTHOR]

Human activities facilitate long-distance dispersal of insects beyond their native range. In particular, the transportation of live plants offers diffusion opportunities for some insects with weak flight abilities. The increase in urban afforestation also help insect reside in urban habitats. The flower thrips, Frankliniella intonsa , is a widespread pest that causes serious damage to many economically important plants. Human activities are likely to facilitate the dispersal of this pest, however, the population genetic structure of this pest remains unclear. Herein, high-throughput sequencing was used to obtain 149 whole mitochondrial genomes of flower thrips from 28 geographic populations in China. Population genetic analyses, phylogenetic reconstruction, and inference of demographic history were then performed. A weak genetic structure was found among all populations across large geographic distance in China, in which five mitochondrial haplotype lineages were resolved. One of the lineages was identified to be shared among most samples collected from central city areas, which may be derived from the surrounding areas. Demographic history analyses suggested a recent population expansion of F. intonsa. Overall, the present population genetic structure of flower thrips in China may be promoted by human-mediated urban afforestation across the country. [ABSTRACT FROM AUTHOR]