New data on mitogenomes of Thienemanniella Kieffer, 1911 (Diptera: Chironomidae, Orthocladiinae).

The mitochondrial genome (mitogenome) has been widely used as a powerful marker in phylogenetic and evolutionary studies of various Dipteran groups. However, only a few mitogenomes from the Thienemanniella genus have been reported till now. Furthermore, there is still indeterminacy in the phylogenetic relationships of the genus Thienemanniella. In this study, mitogenomes of five Thienemanniella species were sequenced and analyzed newly. Combined with the published mitogenome of Thienemanniella nipponica, the obtained results showed that mitogenomes of Thienemanniella were conserved in structure, and all genes were observed to be arranged in the same gene order as the ancestral mitogenome. Nucleotide composition varied significantly among different genes, and the control region displayed the highest A + T content. All protein coding genes are subjected to purification selection, and the fastest evolving gene is ATP8. Maximum likelihood and Bayesian inference analyses showed the phylogeny of Thienemanniella which was supported in five topologies. Our present study provides valuable insight into the phylogenetic relationships of Thienemanniella species.

When did the ancestor of true bugs become stinky? Disentangling the phylogenomics of Hemiptera-Heteroptera.

The phylogeny of true bugs (Hemiptera: Heteroptera), one of the most diverse insect groups in terms of morphology and ecology, has been the focus of attention for decades with respect to several deep nodes between the suborders of Hemiptera and the infraorders of Heteroptera. Here, we assembled a phylogenomic data set of 53 taxa and 3102 orthologous genes to investigate the phylogeny of Hemiptera-Heteroptera, and both concatenation and coalescent methods were used. A binode-control approach for data filtering was introduced to reduce the incongruence between different genes, which can improve the performance of phylogenetic reconstruction. Both hypotheses (Coleorrhyncha + Heteroptera) and (Coleorrhyncha + Auchenorrhyncha) received support from various analyses, in which the former is more consistent with the morphological evidence. Based on a divergence time estimation performed on genes with a strong phylogenetic signal, the origin of true bugs was dated to 290-268 Ma in the Permian, the time in Earth's history with the highest concentration of atmospheric oxygen. During this time interval, at least 1007 apomorphic amino acids were retained in the common ancestor of the extant true bugs. These molecular apomorphies are located in 553 orthologous genes, which suggests the common ancestor of the extant true bugs may have experienced large-scale evolution at the genome level.

Phylogenetic divergences of the true bugs (Insecta: Hemiptera: Heteroptera), with emphasis on the aquatic lineages: the last piece of the aquatic insect jigsaw originated in the Late Permian/Early Triassic.

Heteroptera are among the most diverse hemimetabolous insects. Seven infraorders have been recognized within this suborder of Hemiptera. Apart from the well-established sister-group relationship between Cimicomorpha and Pentatomomorpha (= Terheteroptera), the two terminal lineages, the relationships among the other five infraorders are still controversial, of which three (Gerromorpha, Nepomorpha and Leptopodomorpha) are intimately connected to aquatic environments. However, the various and often conflicting available phylogeny hypotheses do not offer a clear background for a connection between diversification and palaeoenvironments. In this study, a molecular data set representing 79 taxa and 10 149 homologous sites is used to infer the phylogenetic relationships within Heteroptera. Bayesian inference, maximum-likelihood and maximum parsimony analyses were employed. The results of phylogenetic inferences largely confirm the widely accepted phylogenetic context. Estimation of the divergence time based on the phylogenetic results revealed that Gerromorpha, Nepomorpha and Leptopodomorpha originated successively during the period from the Late Permian to Early Triassic (269-246 Ma). This timescale is consistent with the origin and radiation time of various aquatic holometabolans. Our results indicate that the aquatic and semi-aquatic true bugs evolved under environmental conditions of high air temperature and humidity in an evolutionary scenario similar to that of the aquatic holometabolans.

Heissophila macrotheleae Schuh, 2006, the first record of the subfamily Heissophilinae from China (Hemiptera: Heteroptera: Plokiophilidae).

Heissophila Schuh, 2006, a monotypic genus of Heissophilinae (Hemiptera: Plokiophilidae), is newly recorded from Oriental China based on Heissophila macrotheleae Schuh, 2006 collected from Yunnan Province, China. The diagnosis of the species is expanded based on the newly collected materials. In addition, a DNA barcode of H. macrotheleae and host spider are provided. Photographs of the co-existing web-loving bugs and the natural habitat are also present.

Mitogenomes provide new insights of evolutionary history of Boreheptagyiini and Diamesini (Diptera: Chironomidae: Diamesinae).

Mitogenomes have been widely used for phylogenetic reconstruction of various Dipteran groups, but specifically for chironomid, they have not been carried out to resolve the relationships. Diamesinae (Diptera: Chironomidae) are important bioindicators for freshwater ecosystem monitoring, but its evolutionary history remains uncertain for lack of information. Here, coupled with one previously published and 30 new mitogenomes of Diamesinae, we carried out comparative mitogenomic analysis and phylogenetic analysis. Mitogenomes of Diamesinae were conserved in structure, and all genes arranged in the same order as the ancestral insect mitogenome. All protein-coding genes in Diamesinae were under stronger purifying selection than those of other nonbiting midge species, which may exhibit signs of adaptation to life at cold living conditions. Phylogenetic analyses strongly supported the monophyly of Diamesinae, with Boreheptagyiini deeply nested within Diamesini. In addition, phylogenetic relationship of selected six genera was resolved, except Sympotthastia remained unstable. Our study revealed that the mitogenomes of Diamesinae are highly conserved, and they are practically useful for phylogenetic inference.

First Report on Mitochondrial Gene Rearrangement in Non-Biting Midges, Revealing a Synapomorphy in Stenochironomus Kieffer (Diptera: Chironomidae).

(1) Background: Gene rearrangement of mitochondrial genome, especially those with phylogenetic signals, has long fascinated evolutionary biologists. The synapomorphic gene rearrangements have been identified across multiple orders and at many different taxonomic levels, supporting the monophyletic or systematic relationships of related lineages. However, mitochondrial gene rearrangement has never been observed in the non-biting midges (Diptera: Chironomidae); (2) methods: in this study, the complete mitogenomes of seven Stenochironomus species were sequenced and analyzed for the first time; (3) results: each mitogenome of Stenochironomus contains 37 typical genes and a control region. The whole mitogenomes of Stenochironomus species exhibit a higher A+T bias than other published chironomid species. The gene order rearranges from trnI-trnQ-trnM to trnI-trnM-trnQ in all the seven mitogenomes of Stenochironomus, which might be act as a synapomorphy of the genus, supporting the monophyletic of Stenochironomus species. In addition, another derived gene cluster: trnA-trnG-ND3-trnR exists in Stenochironomus tobaduodecimus. The derived gene orders described above are the first case of mitochondrial gene rearrangement in Chironomidae. Coupled with published data, phylogenetic relationships were reconstructed within Chironominae, and strongly supported the monophyly of Stenochironomus; (4) conclusions: our study provides new insights into the mitochondrial gene order of Chironomidae, and provides a valuable resource for understanding the synapomorphic gene rearrangements.

Integrative species delimitation based on COI, ITS, and morphological evidence illustrates a unique evolutionary history of the genus Paracercion (Odonata: Coenagrionidae).

Paracercion are common 'blue and black' colored damselflies. We explore the species boundaries of Paracercion (Odonata: Coenagrionidae) using ABGD, bPTP, GMYC and Distance-based clustering. We finally got the molecular data of all nine species of Paracercion. P. hieroglyphicum and P. melanotum were combined into one putative species based on cytochrome c oxidase I (COI). However, they were separated into two putative species based on the nuclear segment including ITS1-5.8S-ITS2 (ITS). This suggests the introgression of mtDNA in Paracercion. Paracercion barbatum and Paracercion melanotum can be separated into two species based on COI, whereas they were combined into one putative species based on ITS, which suggests a hybridization event between them. The lower interspecific divergence (COI: 0.49%) between P. barbatum and Paracercion v-nigrum indicates a recent speciation event in Paracercion. Paracercion sieboldii and P. v-nigrum can be separated into two putative species based on COI, while they were frequently merged into the same putative species based on ITS. This can be explained by incomplete lineage sorting in nDNA. Besides, P. pendulum and P. malayanum were synonymized as junior synonyms of P. melanotum. P. luzonicum was confirmed not to belong to Paracercion. The possibility of introgression, hybridization, recent speciation and incomplete lineage sorting makes species delimitation, based on molecular data, difficult and complicates understanding of the evolutionary history of Paracercion. The discordance in COI and ITS also indicates the value of using markers from different sources in species delimitation studies.

New or little-known Boreoheptagyia (Diptera, Chironomidae) in China inferred from morphology and DNA barcodes.

The male adult of Boreoheptagyia zhengi Lin & Liu, sp. nov. is described and illustrated based on material collected in China. Associated morphological characteristics and reference to its DNA barcode are provided. Boreoheptagyia kurobebrevis (Sasa & Okazawa, 1992) is newly recorded from China based on both a male and female, with additional associated data on the DNA barcode of the male adult. A neighbor-joining tree based on available Boreoheptagyia DNA barcodes and a key to the adults of Boreoheptagyia from China are given.

Toward a global DNA barcode reference library of the intolerant nonbiting midge genus Rheocricotopus Brundin, 1956.

Environmental DNA metabarcoding is becoming a predominant tool in biodiversity assessment, as this time- and cost-efficient tactics have the ability to increase monitoring accuracy. As a worldwide distributed genus, Rheocricotopus Brundin, 1956 still does not possess a complete and comprehensive global DNA barcode reference library for biodiversity monitoring. In the present study, we compiled a cytochrome c oxidase subunit 1 (COI) DNA barcode library of Rheocricotopus with 434 barcodes around the world, including 121 newly generated DNA barcodes of 32 morphospecies and 313 public barcodes. Automatic Barcode Gap Discovery (ABGD) was applied on the 434 COI barcodes to provide a comparison between the operational taxonomic units (OTU) number calculated from the Barcode Index Number (BIN) with the "Barcode Gap Analysis" and neighbor-joining (NJ) tree analysis. Consequently, these 434 COI barcodes were clustered into 78 BINs, including 42 new BINs. ABGD yielded 51 OTUs with a prior intraspecific divergence of Pmax = 7.17%, while NJ tree revealed 52 well-separated clades. Conservatively, 14 unknown species and one potential synonym were uncovered with reference to COI DNA barcodes. Besides, based on our ecological analysis, we discovered that annual mean temperature and annual precipitation could be considered as key factors associated with distribution of certain members from this genus. Our global DNA barcode reference library of Rheocricotopus provides one fundamental database for accurate species delimitation in Chironomidae taxonomy and facilitates the biodiversity monitoring of aquatic biota.

First complete mitogenomes of Diamesinae, Orthocladiinae, Prodiamesinae, Tanypodinae (Diptera: Chironomidae) and their implication in phylogenetics.

BACKGROUND: The mitochondrial genome (mitogenome) has been extensively used for phylogenetic and evolutionary analysis in Diptera, but the study of mitogenome is still scarce in the family Chironomidae. METHODS: Here, the first complete mitochondrial genomes of four Chironomid species representing Diamesinae, Orthocladiinae, Prodiamesinae and Tanypodinae are presented. Coupled with published mitogenomes of two, a comparative mitochondrial genomic analysis between six subfamilies of Chironomidae was carried out. RESULTS: Mitogenomes of Chironomidae are conserved in structure, each contains 37 typical genes and a control region, and all genes arrange the same gene order as the ancestral insect mitogenome. Nucleotide composition is highly biased, the control region displayed the highest A + T content. All protein coding genes are under purifying selection, and the ATP8 evolves at the fastest rate. In addition, the phylogenetic analysis covering six subfamilies within Chironomidae was conducted. The monophyly of Chironomidae is strongly supported. However, the topology of six subfamilies based on mitogenomes in this study is inconsistent with previous morphological and molecular studies. This may be due to the high mutation rate of the mitochondrial genetic markers within Chironomidae. Our results indicate that mitogenomes showed poor signals in phylogenetic reconstructions at the subfamily level of Chironomidae.

A Cretaceous bug with exaggerated antennae might be a double-edged sword in evolution.

Sexual selection can favor production of exaggerated features, but the high cost of such features in terms of energy consumption and enemy avoidance makes them go to extinction under the influence of natural selection. However, fossils preserved with specialized features are very rare. Here, we report a new nymph from Burmese amber, Magnusantena wuae Du & Chen gen. et sp. nov., which has exaggerated leaf-like expanded antennae. Such bizarre antennae indicate that sensitive and delicate sensory system and magnificent appearance in Hemiptera have been already established in mid-Cretaceous. Our findings may provide evidence for Darwin's view that sensory organs play an important role in sexual selection. This nymph with the leaf-like antennae may also represents a new camouflage pattern. However, the oversized antennae are costly to develop and maintain, increasing the risks from predators. Such unparalleled expanded antennae might be the key factor for the evolutionary fate of the coreid.

DNA barcodes and morphology confirm a new species of Rheocricotopus (Psilocricotopus) orientalis group (Diptera: Chironomidae).

Morphology and DNA barcodes confirm a new chironomid species within the Rheocricotopus (Psilocricotopus) orientalis group (Diptera: Chironomidae). Rheocricotopus (Psilocricotopus) kongi Lin et Wang sp. n. is described and illustrated based on adult male from Hainan, China. Key to adult males of the R. orientalis group is given.

Morphological diversity of the metathoracic spiracle in the Lygaeoidea (Hemiptera: Heteroptera).

Spiracles are the openings in the exoskeleton of insects through which air enters into the respiratory system that is formed by a series of tubes called tracheae. They are primarily located on the abdomen, but can also occur on the thorax, including the metathorax. An insect metathoracic spiracle is usually composed of an external opening and a more internal filter apparatus. We propose new terminology for these structures, and we explore the value in their use in taxonomic and phylogenetic studies within the true bug infraorder Pentatomomorpha, with emphasis on the superfamily Lygaeoidea (Insecta: Hemiptera: Heteroptera). These structures were studied using scanning electron microscopy. Two types of metathoracic spiracle external openings were recognized: a narrow opening (type N), which is slit-like; and a wide opening (type W), with internal fine structures located between the mesothoracic and metathoracic margins of the interpleural suture clearly visible. The filter apparatus in the Pentatomomorpha consists of modified mushroom bodies of the metathoracic scent gland evaporatorium, for which the term mycoid filter processes is proposed. Eight different types of mycoid filter processes, and an unmodified microsculpture type (a type with usual cuticular microsculpture) and filter setae can be found on the anterior or posterior margins of the metathoracic spiracle. We believe the wide opening (type W) to be the plesiomorphic character state in the Pentatomomorpha, with multiple, independent transformations leading to the narrow opening in Lygaeoidea. Considerable variability in the structure of the spiracle opening (in Lygaeoidea), and in the structure of the mycoid filter processes (in Pentatomomorpha) was detected. Overall, we found the morphology of these structures to be of limited value concerning the taxonomy or for determining phylogenetic relationships of the higher taxa (families) of Pentatomomorpha, but they may be useful as additional evidence for taxonomic and phylogenetic studies at the generic and perhaps the tribal levels.

Author Correction: The first amber caridean shrimp from Mexico reveals the ancient adaptation of the Palaemon to the mangrove estuary environment.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A new genus and species of gall midge (Diptera: Cecidomyiidae) inducing leaf galls on Peking lilac, Syringa reticulata subsp. pekinensis (Oleaceae), in China.

Larvae of a previously unknown species of gall midge were found causing large numbers of pustulate leaf galls on Peking lilac, Syringa reticulata subsp. pekinensis (Oleaceae), in parklands and street greenery in Beijing, China. Heavily galled leaves become senescent and fall off prematurely. The gall midge is named Pekinomyia syringae Jiao Kolesik, its morphology is described and the COI mitochondrial gene and 12S ribosomal gene segments are sequenced. A new genus, Pekinomyia Jiao Kolesik (Cecidomyiinae: Lasiopteridi), is erected for the new species. The new genus differs from other Lasiopteridi in the strongly sclerotized aedeagus and the lack of mesobasal lobes in the male terminalia and is not assigned to any known tribe.

The first amber caridean shrimp from Mexico reveals the ancient adaptation of the Palaemon to the mangrove estuary environment.

The aquatic and semiaquatic invertebrates in fossiliferous amber have been reported, including taxa in a wide range of the subphylum Crustacea of Arthropoda. However, no caridean shrimp has been discovered so far in the world. The shrimp Palaemon aestuarius sp. nov. (Palaemonidae) preserved in amber from Chiapas, Mexico during Early Miocene (ca. 22.8 Ma) represents the first and the oldest amber caridean species. This finding suggests that the genus Palaemon has occupied Mexico at least since Early Miocene. In addition, the coexistence of the shrimp, a beetle larva, and a piece of residual leaf in the same amber supports the previous explanations for the Mexican amber depositional environment, in the tide-influenced mangrove estuary region.

New Mycodiplosis gall midge (Diptera: Cecidomyiidae) feeding on fungal rusts (Fungi: Pucciniomycetes) that are pathogenic on cultured plants.

Larvae of a gall midge were found feeding on the fungal rust Maravalia pterocarpi (Pucciniomycetes: Pucciniales: Chaconiaceae) infesting the economically important sua tree Dalbergia tonkinensis (Fabaceae) on Hainan Island, China. The adults, pupae and larvae were collected, their morphology was studied and a segment of the Cytochrome Oxidase unit I (COI) mitochondrial gene was sequenced. The gall midge proved to be a species new to science that belongs to the genus Mycodiplosis (Diptera: Cecdiomyiidae). Comparison of the sequence to published Cecdiomyiidae sequences revealed that, despite being undescribed and unnamed, it was previously found in east and south-east Asia to feed on several rust species: Puccinia coronata (Pucciniomycetes: Pucciniales: Pucciniaceae) that develops on Lolium multiflorum (Poaceae), Puccinia sp. on Zea mays (Poaceae), Puccinia arachidis on Arachis hypogaea (Fabaceae) and Puccinia allii on Allium fistulosum (Amaryllidaceae). The new species is described and named here Mycodiplosis puccinivora Jiao, Bu Kolesik. It occurs in China, Japan, Thailand, Bangladesh and possibly Malaysia and Australia. In Hainan it has four to five generations per year.

A mitochondrial genome of Micronectidae and implications for its phylogenetic position.

The mitochondrial genome (mitogenome) has been extensively used to better understand the phylogenetic relationships within the heteropteran infraorder Nepomorpha (Hemiptera), but no mitogenome in Micronectidae has been sequenced to date. Here we describe the first complete mitogenome of Micronecta sahlbergii (Jakovlev, 1881). The mitogenome is 15,005 bp in size, containing 13 typical PCGs, 22 tRNAs, two rRNAs and a control region (CR). All genes are arranged in the same gene order as the most other known heteropteran mitogenome. The phylogenetic relationships based on mitogenomes using Bayesian inference and Maximum likelihood methods showed that Micronecta sahlbergii was sister to Sigara septemlineata, suggesting that Micronecta sahlbergii belongs to Corixoidea. Corixoidea was basal within Nepomorpha. The PCG12 and PCG12RT matrices of BI and ML analyses yielded the consistent topology, respectively. Whereas there was no consistent conclusions in PCG123 and PCG123RT matrices. Saturation tests showed that PCG12 and PCG12RT were free of saturation in evaluation of transition and transversion substitution, while PCG123 and PCG123RT exhibited a plateau revealing saturation of transition suggesting that the third codon positions of PCGs were not suitable for addressing relationships at the superfamily level in Nepomorpha. So our results supported the phylogenetic analysis of PCG12 and PCG12RT in Nepomorpha.

A new species of Procontarinia (Diptera: Cecidomyiidae) damaging fruit of mango, Mangifera indica (Anacardiaceae), in China.

Larvae of a previously unknown species of gall midge were found feeding on young fruit of mango, Mangifera indica (Anacardiaceae), in Guangxi Autonomous Region in southern China, causing severe damage to the crop. The new species is named Procontarinia fructiculi Jiao, Wang, Bu Kolesik, its morphology is described, the basic biology is given, and the Cytochrome Oxidase subunit I (COI) mitochondrial gene segment is sequenced and compared to other congeners. Procontarinia contains now 16 described species, each feeding on mango. All but three species cause variously shaped galls on leaves, while P. mangiferae (Felt) malforms inflorescence and young leaves, and two species feed on fruit - P. frugivora Gagné causing deep lesions and P. fructiculi sp. nov. tunnel-like holes. Of the two fruit-feeding species, P. frugivora is confined to the Philippines while the new species has thus far been recorded only from southern China.

A new species of Contarinia (Diptera: Cecidomyiidae) damaging inflorescence of Carya cathayensis (Juglandaceae) in China.

Chinese hickory, Carya cathayensis Sargent (Juglandaceae), is a tree naturally occurring and industrially grown in China for the nuts that are valued for their taste and nutrient content. Larvae of a previously unknown species of gall midge were found feeding on male and female inflorescences of Carya cathayensis in Zhejiang and Anhui Provinces in eastern China, reducing pollination and fruit development, and causing substantial damage to the nut industry. The new species is named Contarinia caryafloralis Jiao, Bu Kolesik, its morphology is described, the basic biology is given, and the Cytochrome Oxidase subunit I (COI) mitochondrial gene segment is sequenced. Contarinia caryafloralis is the first gall midge known to feed on a Carya species native to Asia.