A new species of Rhopalopsole (Plecoptera, Leuctridae) from Hainan Province, China

Background

Hainan Province is an island in the south of China and belongs to the Oriental Region. It has a unique geographical location and superior climatic conditions, providing a good living environment for Leuctridae insects. However, the species richness of the stonefly family Leuctridae in Hainan is low. Two species in total have been recorded, Rhopalopsolebawanglinga Li, Li & Yang, 2023 and Rhopalopsolehainana Li & Yang, 2010.

New information

A new species of Leuctridae (Plecoptera) from Wuzhi Mountains, Hainan Province of south China, Rhopalopsolewuzhishana sp. nov. is described and illustrated. We summarised the Leuctridae in Hainan Province and provide supplemental description and colour plates of Rhopalopsolehainana Li & Yang, 2010.

The small heat shock protein Hsp20.8 imparts tolerance to high temperatures in the leafminer fly, Liriomyza trifolii (Diptera: Agtomyzidae)

As an environmental factor, temperature impacts the distribution of species and influences interspecific competition. The molecular chaperones encoded by small heat shock proteins (sHsps) are essential for rapid, appropriate responses to environmental stress. This study focuses on Hsp20.8, which encodes a temperature-responsive sHsp in Liriomyza trifolii, an insect pest that infests both agricultural and ornamental crops. Hsp20.8 expression was highest at 39℃ in L. trifolii pupae and adults, and expression levels were greater in pupae than in adults. Recombinant Hsp20.8 was expressed in Escherichia coli and conferred a higher survival rate than the empty vector to bacterial cells exposed to heat stress. RNA interference experiments were conducted using L. trifolii adults and prepupae and the knockdown of Hsp20.8 expression increased mortality in L. trifolii during heat stress. The results expand our understanding of sHsp function in Liriomyza spp. and the ongoing adaptation of this pest to climate change. In addition, this study is also important for predicting the distribution of invasive species and proposing new prevention and control strategies based on temperature adaptation.

The development of abamectin resistance in Liriomyza trifolii and its contribution to thermotolerance

BACKGROUND

Liriomyza trifolii is an economically significant, invasive pest of horticultural and vegetable crops. The larvae form tunnels in foliage and hasten senescence and death. Outbreaks of L. trifolii often erupt in hot weather and are driven by thermotolerance; furthermore, the poor effectiveness of pesticides has made outbreaks more severe. But it is still unclear whether the development of insecticide tolerance will contribute to thermotolerance in L. trifolii.

RESULTS

To explore potential synergistic relationships between insecticide exposure and thermotolerance in L. trifolii, we first generated an abamectin-resistant (AB-R) strain. Knockdown behavior, eclosion and survival rates, and expression levels of genes encoding heat shock proteins (Hsps) in L. trifolii were then examined in AB-R and abamectin-susceptible (AB-S) strains. Our results demonstrated that long-term selection pressure for abamectin resistance made L. trifolii more prone to develop cross-resistance to other insecticides containing similar ingredients. Furthermore, the AB-R strain exhibited enhanced thermotolerance and possessed an elevated critical thermal maximum temperature, and upregulated expression levels of Hsps during heat stress.

CONCLUSION

Collectively, our results indicate that thermal adaptation in L. trifolii was accompanied by emerging abamectin resistance. This study provides a theoretical basis for investigating the synergistic or cross-adaptive mechanisms that insects use to cope with adversity and demonstrates the complexity of insect adaptation to environmental and chemical stress. © 2023 Society of Chemical Industry.

Characterization of genes encoding heat shock proteins reveals a differential response to temperature in two geographic populations of Liriomyza trifolii (Diptera: Agromyzidae)

Liriomyza trifolii is a significant, invasive pest that damages horticultural crops and vegetables. The distribution of L. trifolii is influenced by temperature, and prior research has demonstrated that variations in thermal adaptability differ among geographic populations of the insect. Heat shock proteins (Hsps) are involved in adaptation to temperatures; however, the underlying molecular mechanism for thermal adaption in different L. trifolii populations remains unclear. This study examines the temperature adaptability of two L. trifolii populations from Hainan (HN) and Jiangsu (JS) provinces. The results indicate that the HN population has a higher survival rate and a higher critical thermal maximum (CTmax) than the JS population under high temperature stress. Transcriptome data at 42 °C revealed that the JS population has more differentially expressed genes (DEGs) than the HN population, while the HN population has more upregulated DEGs. The two populations were similar in functional annotation of DEGs, and a large number of Hsps were upregulated. However, the HN population had larger numbers and higher expression levels of Hsps during heat stress as compared to the JS population. Additionally, the expression patterns of differentially expressed Hsps varied between the HN and JS populations in response to different elevated temperatures. Notably, the transcription levels of Hsp70s were higher in the HN population as compared to the JS population, while the expression level of genes encoding small heat shock proteins was higher in the JS population. These findings have significant scientific value in understanding the underlying mechanism of temperature adaption in L. trifolii and provide a fresh perspective on the distribution of this invasive pest.

The regulation of inhibitor of apoptosis proteins (IAPs) during the apoptosis of Cotesia chilonis

Inhibitor of apoptosis proteins (IAPs) are crucial components of apoptosis that perform vital roles in the regulation of caspase activity in organisms. In this study, two IAPs genes were identified from Cotesia chilonis, the dominant parasitic wasp of Chilo suppressalis. CcIAP1 gene is a typical IAP and contains two BIR domains and a RING domain, whereas CcIAP gene is an atypical IAP1 only containing two BIR domains. Phylogenetic analysis indicated that CcIAP1 and CcIAP were grouped with other Hymenopteran IAPs and IAP1 in C. suppressalis. Real-time quantitative PCR revealed that CcIAP1 and CcIAP genes were both highly induced at -6°C and 30°C, and expression was highest at the third instar stage. The expression of CcIAP1 and CcIAP genes were significantly induced during parasitism of C. suppressalis, and the 7-d time point resulted in the highest expression levels for both genes, in which was an advanced stage of larval development of C. chilonis. RNAi experiments showed that CcIAP1 gene was the key IAP in the regulation of apoptosis of C. chilonis and its host. In conclusion, CcIAP1 and CcIAP correlate with the development of C. chilonis and their responses to temperature stress.

Three new species of Illiesonemoura Baumann, 1975 (Plecoptera, Nemouridae) from China

Background

The genus Illiesonemoura Baumann, 1975 (Plecoptera, Nemouridae) is a small-sized stonefly with slender and curved embranous cerci. Currently, 18 species of the genus are known worldwide, mainly distributed in the Palaearctic and Oriental Regions, with a total of two species known to China.

New information

Three new species of Illiesonemoura Baumann, 1975, I.bituberculata Wang & Du, sp. nov., I.motuoensis Du & Ji, sp. nov. and I.weii Du & Ji, sp. nov. are described and illustrated, based on male adults from China. Illiesonemourabituberculata is characterised by two pairs of tubercles arising posteromedially from tergum 10 and by two rows of spinules outlining the lateral edge of the ventral sclerite of the epiproct. Illiesonemouramotuoensis is characterised by the heart-shaped epiproct with a thin and slightly sclerotised protrusion between the sclerotised bands. Illiesonemouraweii is characterised by a pair of small knobs on tergum 10, outer lobes of paraprocts basally broad, then slender towards apices with a pointed tip and the epiproct with lateral spinules.

The First Complete Mitochondrial Genome of Genus Isocapnia (Plecoptera: Capniidae) and Phylogenetic Assignment of Superfamily Nemouroidea

Capniidae are a family of stoneflies, also known as snow flies, who emerge in winter. The phylogeny of Capniidae is widely accepted to be based on morphological analysis. Until now, only five Capniidae mitochondrial genomes have been sequenced so far. In addition, sampling is required to determine an accurate phylogenetic association because the generic classification of this family is still controversial and needs to be investigated further. In this study, the first mitogenome of genus Isocapnia was sequenced with a length of 16,200 bp and contained 37 genes, including a control region, two rRNAs, 22 tRNAs, and 13 PCGs, respectively. Twelve PCGs originated with the common start codon ATN (ATG, ATA, or ATT), while nad5 used GTG. Eleven PCGs had TAN (TAA or TAG) as their last codon; however, cox1 and nad5 had T as their final codon due to a shortened termination codon. All tRNA genes demonstrated the cloverleaf structure, which is distinctive for metazoans excluding the tRNASer1 (AGN) that missed the dihydrouridine arm. A Phylogenetic analysis of the superfamily Nemouroidea was constructed using thirteen PCGs from 32 formerly sequenced Plecoptera species. The Bayesian inference and maximum likelihood phylogeny tree structures derived similar results across the thirteen PCGs. Our findings strongly supported Leuctridae + ((Capniidae + Taeniopterygidae) + (Nemouridae + Notonemouridae)). Ultimately, the best well-supported generic phylogenetic relationship within Capniidae is as follows; (Isocapnia + (Capnia + Zwicknia) + (Apteroperla + Mesocapnia)). These findings will enable us to better understand the evolutionary relationships within the superfamily Nemouroidea and the generic classification and mitogenome structure of the family Capniidae.

Mechanistic effects of microwave radiation on pupal emergence in the leafminer fly, Liriomyza trifolii

Liriomyza trifolii is a significant pest of vegetable and ornamental crops across the globe. Microwave radiation has been used for controlling pests in stored products; however, there are few reports on the use of microwaves for eradicating agricultural pests such as L. trifolii, and its effects on pests at the molecular level is unclear. In this study, we show that microwave radiation inhibited the emergence of L. trifolii pupae. Transcriptomic studies of L. trifolii indicated significant enrichment of differentially expressed genes (DEGs) in 'post-translational modification, protein turnover, chaperones', 'sensory perception of pain/transcription repressor complex/zinc ion binding' and 'insulin signaling pathway' when analyzed with the Clusters of Orthologous Groups, Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes databases, respectively. The top DEGs were related to reproduction, immunity and development and were significantly expressed after microwave radiation. Interestingly, there was no significant difference in the expression of genes encoding heat shock proteins or antioxidant enzymes in L. trifolii treated with microwave radiation as compared to the untreated control. The expression of DEGs encoding cuticular protein and protein takeout were silenced by RNA interference, and the results showed that knockdown of these two DEGs reduced the survival of L. trifolii exposed to microwave radiation. The results of this study help elucidate the molecular response of L. trifolii exposed to microwave radiation and provide novel ideas for control.

Depending on different apoptosis pathways, the effector Cscaspase-3 in Chilo suppressalis exposed to temperature and parasitic stress was induced

Apoptosis is a form of programmed cell death (PCD) that is largely triggered by caspases through both the mitochondria-dependent and mitochondria-independent pathways. The rice stem borer, Chilo suppressalis, serves as an economically important pest of rice, which is often suffered by temperature and parasitic stress under natural conditions. In the present study, effector Cscaspase-3 encoding caspase was obtained from the rice pest Chilo suppressalis. CsCaspase-3 possesses p20 and p10 subunits, two active sites, four substrate-binding sites, and two cleavage motifs. Real-time quantitative PCR showed that Cscaspase-3 was expressed at maximal levels in hemocytes; furthermore, transcription was most highly in female adults. Expression of Cscaspase-3 was induced by hot and cold temperatures, with the highest expression at 39 °C. Cscaspase-3 expression was also significantly induced at 10 h, 2 d, 5 d, and 7 d of parasitism. Flow cytometry results showed that both temperature and parasitism trigger apoptosis, but only parasitism induces apoptosis via the mitochondrial apoptosis pathway in C. suppressalis. RNAi-mediated silencing of Cscaspase-3 expression reduced C. suppressalis survival at -3 °C. This study provides a foundation for further studies of caspases in insects during biotic and abiotic stress.

Chilo suppressalis heat shock proteins are regulated by heat shock factor 1 during heat stress

Heat shock factor 1 (HSF1) functions to maintain cellular and organismal homeostasis by regulating the expression of target genes, including those encoding heat shock proteins (HSPs). In the present study, the gene encoding HSF1 was cloned from the rice pest Chilo suppressalis, and designated Cshsf1. The deduced protein product, CsHSF1, contained conserved domains typical of the HSF1 family, including a DNA-binding domain, two hydrophobic heptad repeat domains, and a C-terminal transactivation domain. Real-time quantitative PCR showed that Cshsf1 was highly expressed in hemocytes. Expression analysis in different developmental stages of C. suppressalis revealed that Cshsf1 was most highly expressed in male adults. RNAi-mediated silencing of Cshsf1 expression reduced C. suppressalis survival at high temperatures. To investigate the regulatory interactions between Cshsf1 and Cshsps, the promoters and expression patterns of 18 identified Cshsps in C. suppressalis were analysed; four types of heat shock elements (HSEs) were identified in promoter regions including canonical, tail-tail, head-head, and step/gap. The expression of Cshsp19.0, Cshsp21.7B, Cshsp60, Cshsp70 and Cshsp90 was positively regulated by Cshsf1; however, Cshsp22.8, Cshsp702, Cshsp705 and Cshsp706 gene expression was not altered. This study provides a foundation for future studies of HSF1 in insects during thermal stress.

The First Study of Mating Mistakes in Stoneflies (Plecoptera) from China, with Remarks on Their Biological Implications

Currently, information on the biology of Plecoptera from China is scarce, particularly on mating behavior. In this paper, the existence of mating mistakes (erroneous mating attempts) involving 13 Chinese stonefly species (belonging to nine genera and three families) is reported. These erroneous mating behaviors can be included into three different categories: mating attempts between conspecific males (including the formation of erroneous mating balls), mating attempts between different taxa (including displacement attempts during copulation), and mating-related behaviors with non-living objects. From these behaviors, some aspects of stoneflies during mating, such as the physical competition between males, the sensorial mechanisms implied in triggering a mating behavior, the conditions favoring the mating mistakes, and the possible consequences of interspecific mating in the hybrid production, are discussed.

Additions to the fauna and biology of stoneflies (Plecoptera) in Taizi River Basin, Liaoning, with seven new species records to China

Background

An investigation report of stonefly fauna in Benxi Manchu Autonomous County, Liaoning Province, northeast China (used to be called Manchuria, now includes Liaoning, Jilin, Heilongjiang Provinces and parts of Inner Mongolia, which are adjacent to the Russian Far East and the Korean Peninsula). Materials were studied with field observation in 2018 and 2019.

New information

This paper records five families, nine genera and 14 species of stoneflies from Taizi River, Liaoning Province. Nine species have been recorded for the first time in China and the biology of several common species is also reported for the first time.

New Synonym and New Species Record of Filchneria (Plecoptera: Perlodidae) from China with a Morphological, Phylogenetic and Biogeographic Study on This Genus

The type species of Filchneria Klapálek, 1908, F. mongolica (Klapálek, 1901), is based on a single female collected from Mongolia, but it was considered the same as another species, F. songi from Qinling, China, when the genus Filchneria was proposed. This study narrates the story of these two species, which have been confused for a century. Until now, the distribution of F. mongolica has been confirmed only in Mongolia and Russia, and we recently recorded it for the first time in Inner Mongolia as a new species record in China. Additionally, the genus Sinoperlodes is a junior synonym of Filchneria, as demonstrated by both the morphological and molecular analysis. Phylogenetic analysis based on the subfamily Perlodinae is provided, along with morphological and biogeographic comparisons of Filchneria and its relatives.

New Synonym and New Species Record of Filchneria (Plecoptera: Perlodidae) from China with a Morphological, Phylogenetic and Biogeographic Study on This Genus

The type species of Filchneria Klapálek, 1908, F. mongolica (Klapálek, 1901), is based on a single female collected from Mongolia, but it was considered the same as another species, F. songi from Qinling, China, when the genus Filchneria was proposed. This study narrates the story of these two species, which have been confused for a century. Until now, the distribution of F. mongolica has been confirmed only in Mongolia and Russia, and we recently recorded it for the first time in Inner Mongolia as a new species record in China. Additionally, the genus Sinoperlodes is a junior synonym of Filchneria, as demonstrated by both the morphological and molecular analysis. Phylogenetic analysis based on the subfamily Perlodinae is provided, along with morphological and biogeographic comparisons of Filchneria and its relatives.

Insect hormones affect the toxicity of the insecticidal growth regulator cyromazine in Liriomyza trifolii (Diptera: Agromyzidae)

The leafminer Liriomyza trifolii is an important insect pest of ornamental and vegetable crops worldwide. Cyromazine is an effective, commonly-used insecticide that functions as a growth regulator, but its effect on L. trifolii has not been previously reported. In this study, transcriptome analysis was undertaken in L. trifolii exposed to cyromazine. Clusters of orthologous groups analysis indicated that a large number of differentially expressed genes responding to cyromazine were categorized as "lipid transport and metabolism", "post-translational modification, protein turnover, chaperones", and "cell wall/membrane/envelope biogenesis". Gene ontology analysis indicated that pathways associated with insect hormones, growth and development, and cuticle synthesis were significantly enriched. In general, the transcriptome results showed that the genes related to insect hormones were significantly expressed after treatment with cyromazine. Furthermore, the combined exposure of L. trifolii to cyromazine and the hormone analogues 20-hydroxyecdysone (20E) or juvenile hormone (JH) indicated that hormone analogues can change the expression pattern of hormone-related genes (20EP and JHEH) and pupal length. The combined application of cyromazine with 20E improved the survival rate of L. trifolii, whereas the combination of JH and cyromazine reduced survival. The results of this study help elucidate the mechanistic basis for cyromazine toxicity and provide a foundation for understanding cyromazine resistance.

RNA Interference of Chitin Synthase 2 Gene in Liriomyza trifolii through Immersion in Double-Stranded RNA

Liriomyza trifolii is an important invasive pest that infects horticultural vegetables, displaying a strong competitive advantage and showing great potential for inflicting harm. Chitin synthase is one of the key enzymes in insect chitin metabolism and plays an important role in insect growth and development. In this study, a chitin synthase (CHS) transcript of L. trifolii was cloned, and the results showed that LtCHS belongs to the CHS2 family. The expression analysis indicated the presence of the highest abundance of LtCHS2 in the pupae at different developmental stages but showed no significant difference among different tissues in the adult. Furthermore, a dsRNA immersion method was developed for RNA interference (RNAi) in L. trifolii using LtCHS2 transcript. RNAi can significantly reduce the expression of LtCHS2 in pupae, and the emergence rate of the pupae was significantly lower than that of the control. The results provide a theoretical basis for exploring the role of chitin synthase gene in L. trifolii and proposing new pest control strategies.

Transcriptome analysis and screening of putative sex-determining genes in the invasive pest, Frankliniella occidentalis (Thysanoptera: Thripidae)

The invasive insect pest, Frankliniella occidentalis, is a well-known vector that transmits a variety of ornamental and vegetable viruses. The mechanistic basis of sex determination in F. occidentalis is not well understood, and this hinders our ability to deploy sterile insect technology as an integrated pest management strategy. In this study, six cDNA libraries from female and male adults of F. occidentalis (three biological replicates each) were constructed and transcriptomes were sequenced. A total of 6000 differentially-expressed genes were identified in the two sexes including 2355 up- and 3645 down-regulated genes. A total of 149 sex-related genes were identified based on GO enrichment data and included transformer-2 (tra2), fruitless (fru), male-specific lethal (msl) and sex lethal (sxl); several of these exhibited sex-specific and/or sex-biased expression in F. occidentalis. This study contributes to our understanding of the sex-determined cascade in F. occidentalis and other members of the Thysanoptera.

A review of Leuctridae (Insecta, Plecoptera) in Wuyi Mountains, China

Background

Wuyi Mountains are located in the northern Oriental Region and the edge of the southern Palaearctic Region. They have a unique geographical location, complex landform and superior climatic conditions, providing a good ecological environment for Leuctridae species. However, due to the damage of some holotypes in the 20^th century, limited drawings and lack of colour figures, it is necessary to reorganise and supplement the preserved Leuctridae specimens from Wuyi Mountains.

New information

In this study, we found that there are twelve species of Leuctridae recorded in Wuyi Mountains, accounting for about 20% of the recorded species of Leuctridae in China. These records include two genera and five new distribution records species: one species of the genus Paraleuctra Hanson, 1941: Paraleuctraorientalis (Chu 1928) and eleven species of the genus Rhopalopsole Klapálek, 1912, including five new distribution records to Wuyi Mountains: Rhopalopsolefengyangshanensis Yang, Shi & Li, 2009; Rhopalopsolesinensis Yang & Yang, 1993; Rhopalopsoleyangdingi Sivec & Harper, 2008; Rhopalopsoleflata Yang & Yang, 1995; Rhopalopsolebasinigra Yang & Yang, 1995. Now a total of twelve species of Leuctridae have been recorded from Wuyi Mountains, Fujian Province of south-eastern China. In this paper, we also provide a key to the male, new images and some notes of these twelve species, except Rhopalopsolerecurvispina (Wu, 1949) and Rhopalopsolespiniplatta (Wu, 1949). We failed to collect these two species and we regard R.recurvispina as a nomen dubium, because there are no distinctive features that can be used to distinguish this species.

A new species of Sweltsa Ricker, 1943 (Plecoptera, Chloroperlidae) and a supplementary description of Sweltsahamula Chen & Du, 2017 from China

Background

The genus Sweltsa is a small to medium-sized stonefly with distinct coloured wings, giving the species the common name of green stoneflies. It belongs to the family Chloroperlidae. This genus includes more than 55 species world wide, 14 of which have been reported from China.

New information

A new species of the genus Sweltsa Ricker, 1943, Sweltsaliupanshana Rehman, Du & Huo sp. nov. from Ningxia Hui Autonomous Region, Liupan Mountain, China is described; this is the second record of Sweltsa from Ningxia Hui Autonomous Region. In addition, the first female description and male supplementary description of Sweltsahamula Chen & Du, 2017 from Sichuan Province are provided. Diagnosis, description and colour illustration of the new species and of Sweltsahamula are provided and the morphological characteristics are compared with closely-related species.

Identification, expression analysis and functional verification of two genes encoding small heat shock proteins in the western flower thrips, Frankliniella occidentalis (Pergande)

Small heat shock proteins (sHSPs) help prevent the irreversible aggregation of denatured proteins that occurs in response to organismal stress. In this study, we identified two intron-free genes encoding sHSPs from Frankliniella occidentalis; these were designated FoHSP11.6 and FoHSP28.0 and belonged to an atypical and typical sHSP family, respectively. Both FoHSPs were transcribed in all developmental stages of F. occidentalis with the highest expression levels in pupae and adults and greater expression in males than females. Although the FoHSPs had different temperature-induced expression profiles, they were generally induced by both low and high temperatures and reached maximal expression levels after 0.5-1 h of temperature stress. The FoHSPs expression levels in pupae were induced by drought and high humidity, and higher expression levels were correlated with lower survival rates. The thermotolerance of F. occidentalis decreased when theFoHSPs were silenced by RNA interference. Our results show that FoHSP11.6 and FoHSP28.0 are involved in the response to temperature and drought and may also function in growth and development of F. occidentalis.

Two New Synonyms of Paraleuctra orientalis (Chu, 1928) (Plecoptera: Leuctridae) Based on Morphological and Molecular Data, with Notes on Paraleuctra cervicornis Du and Qian, 2012

Simple Summary

Paraleuctra Hanson, 1941, is a widespread genus distributed in the east and west Nearctic and in much of the Palaearctic, with 27 valid species currently known. In China, although six Paraleuctra species have been reported, the differences among these species have not been fully explained. After checking a large number of specimens of this genus from Zhejiang Province, two junior synonyms are proposed for the species Paraleuctra orientalis (Chu, 1928).

Abstract

We recently examined specimens of the genus Paraleuctra Hanson, 1941, from Zhejiang Province and Sichuan Province, China, and two new synonyms are established based on morphological and molecular data. Paraleuctra sinica Yang and Yang, 1995, and Paraleuctra tianmushana Li and Yang, 2010, are synonymized with Paraleuctra orientalis (Chu, 1928). Additionally, we provide new images of Paraleuctra cervicornis Du and Qian, 2012, to facilitate identification of this species.

Mechanisms of fungal community assembly in wild stoneflies moderated by host characteristics and local environment

Deterministic and stochastic forces both drive microbiota assembly in animals, yet their relative contribution remains elusive, especially in wild aquatic-insect-associated fungal communities. Here, we applied amplicon sequencing to survey the assembly mechanisms of the fungal community in 155 wild stonefly individuals involving 44 species of 20 genera within eight families collected from multiple locations in China. Analysis showed that fungal diversity and network complexity differed significantly among the eight stonefly families, and that the fungal communities in stoneflies exhibited a significant distance-decay pattern across large spatial scales. Both a structural equation model and variance partitioning analysis revealed that environmental factors (e.g., geographical, climatic) outweigh host attributes in shaping the fungal community of stoneflies. Using neutral and null model analyses, we also find that deterministic processes play a larger role than stochasticity in driving the fungal community assembly. However, the relative contribution of ecological processes including dispersal, drift, and selection, varied strongly with host taxonomy. Furthermore, environmental conditions also significantly affect the strength of these ecological processes. Overall, our findings illustrate that variations in host attributes and environment factors may moderate the relative influence of deterministic and stochastic processes to fungal community composition in wild stoneflies, which provides new insights into mechanisms of microbial community assembly in aquatic arthropods.

A new species of the genus Sweltsa Ricker, 1943 (Plecoptera, Chloroperlidae) from Guizhou Province, China

Background

Sweltsa is a genus of green stoneflies in the family Chloroperlidae and is distributed throughout the Nearctic and East Palaearctic Regions. As they are sensitive to pollutants, they are often used as an indicator species for determining the quality of water bodies. There are around 57 species of this genus worldwide and 11 of those have been identified from China.

New information

A new species of the Alloperlini genus Sweltsa Ricker, 1943, Sweltsaligula Rehman, Huo & Du sp. n. is described from Kuankuoshui National Natural Reserve, Suiyang County, Guizhou Province, southwest China. This is the first report of the family Chloroperlidae from Guizhou Province. Diagnosis, description of male, female and nymph, illustration of terminalia and similarities with closely-related species are provided and discussed.

A new species of Suwallia Ricker, 1943 (Plecoptera, Chloroperlidae) from southwestern China, with an updated key to male Suwallia species

A new species of the genus Suwallia Ricker, 1943 (Plecoptera, Chloroperlidae), Suwalliadengbasp. nov., is described from Tibet and Yunnan, southwestern China. A diagnosis and description of the adult habitus and aedeagal structure are illustrated with color images. Similarities in the terminalia with closely related species are discussed. In addition, an updated key to adult males of the Suwallia species of China is provided.

Isolation of two new genes encoding heat shock protein 70 in Bemisia tabaci and analysis during thermal stress

The heat shock protein 70 family (HSP70) is among the most varied HSP family with respect to structure and function. The phloem-feeding insect Bemisia tabaci (Gennadius) is an important pest of cotton, vegetables and ornamentals that transmits several plant viruses and causes enormous agricultural losses. In this study, two new HSP70 genes (Bthsp70-2 and Bthsp70-3) were isolated from the MED cryptic species B. tabaci, an important phloem-feeding pest of vegetables and ornamentals. Bthsp70-2 and Bthsp70-3 encoded proteins comprised of 652 and 676 amino acids, and the deduced proteins were closely related to other HSP70s in Hemiptera. Expression analyses using real-time quantitative PCR indicated that Bthsp70-2 and Bthsp70-3 were induced in B. tabaci pupae and adults during high and low thermal stress. Bthsp70-2 and Bthsp70-3 exhibited similar, but not identical, expression patterns when exposed to different durations of high temperature stress. Oral ingestion of dsBthsp70 reduced the expression level of Bthsp70-2 and Bthsp70-3 in B. tabaci and increased the mortality of B. tabaci during heat shock. In conclusion, Bthsp70-2 and Bthsp70-3 exhibit different expression patterns during thermal stress, thus expanding the roles of HSPs in B. tabaci.

Differential Response of Leafminer Flies Liriomyza trifolii (Burgess) and Liriomyza sativae (Blanchard) to Rapid Cold Hardening

Simple Summary

Liriomyza trifolii (Burgess) and L. sativae (Blanchard) are closely-related, polyphagous leafminers that occur worldwide and presumably compete with each other. In this study, we evaluated the response of pupae and adults from both species to acute (2 h) cold exposures. The results were used to identify the lethal temperature for 80% of the population (LT80) for each species. In a separate set of experiments, insects were cooled to one of six nonlethal temperatures (0–5 °C) for 4 h and then cooled to the LT80 for 2 h to evaluate their rapid cold hardening (RCH) response. L. trifolii exhibited stronger cold tolerance than L. sativae; furthermore, the supercooling point of L. trifolii was significantly lower than that of L. sativae. RCH was induced in pupae of both species at a range of low temperatures (0–5 °C), and L. sativae pupae showed a more robust RCH response (e.g., lower supercooling pointand more durable RCH) than L. trifolii pupae. Our results indicate that subtle differences in RCH and basal cold tolerance impact the competitiveness of the two leafminers.

Abstract

Rapid cold hardening (RCH) is a rapid and critical adaption of insects to sudden temperature changes but is often overlooked or underestimated as a component of survival. Thus, interspecific comparisons of RCH are needed to predict how phenotypes will adapt to temperature variability. RCH not only enhances cold survival but also protects against non-lethal cold injury by preserving essential functions such as locomotion, reproduction, and energy balance. This study investigated the difference in basal cold tolerance and RCH capacity of L. trifolii and L. sativae. In both species, the cold tolerance of pupae was significantly enhanced after short-term exposure to moderately cold temperatures. The effect of RCH last for 4 h in L. sativae but only 2 h in L. trifolii. Interestingly, L. trifolii adults had a RCH response but L. sativae adults failed to acclimate. Short-term acclimation also lowered the supercooling point significantly in the pupae of both species. Based on these results, we propose a hypothesis that these differences will eventually affect their competition in the context of climate change. This study also provides the basis for future metabolomic and transcriptomic studies that may ultimately uncover the underlying mechanisms of RCH and interspecific competition between L. trifolii and L. sativae.

Transcriptome analysis reveals gene expression differences in Liriomyza trifolii exposed to combined heat and abamectin exposure

Liriomyza trifolii is an invasive pest of horticultural and vegetable crops that possesses robust competitive advantages that enable it to replace closely-related species. High temperatures often occur concomitantly with insecticide usage during L. trifolii outbreaks. In this study, we compared the transcriptomes of L. trifolii exposed to high temperature (40 °C T40), insecticide (LC₅₀ of technical grade abamectin, I50) and combined high temperature and abamectin exposure (IT5040, I50 followed by T40; and TI4050, T40 followed by I50). RNA-seq generated and revealed 44,633 unigenes with annotation data; these were compared with COG and KEGG databases for functional classification and enrichment analysis. Compared with the I50 treatment, COG classification indicated that ‘post-translational modification, protein turnover, chaperones’ was enriched in the IT5040 treatment. In the TI4050 treatment, ‘carbohydrate transport and metabolism’ was the most abundant group. The most enriched KEGG pathways in the TI4050 and IT5040 treatments were ‘longevity regulating pathway - multiple species’ and ‘protein processing in endoplasmic reticulum’, respectively. Subsequent annotation and enrichment analyses indicated that stress-related genes such as CYP450s and HSPs were differentially expressed in the I50 vs. TI4050 or I50 vs. IT5040 treatment groups. Three commercial insecticide formulations were also used to further verify the expression of selected differentially-expressed genes. This study will be conductive to consider the temperature effect on insecticide tolerance in L. trifolii, and provides a framework for improving the application efficiency of insecticides in hot weather, which will ultimately reduce the overuse of pesticides.

Differential regulation of antioxidant enzymes in Frankliniella occidentalis (Thysanoptera: Thripidae) exposed to thermal stress

Frankliniella occidentalis is an invasive insect pest that incites damage to ornamental and agronomic crops on a global scale. In this study, the effects of temperature on gene expression and enzyme activity were studied for superoxide dismutase (SOD), peroxidase (POD), and glutathione-S-transferase (GST) in F. occidentalis. SOD, POD and GST enzyme activity increased significantly at 35–37 °C but declined as the temperature increased to 41 °C. In a time course study at 35 °C, SOD, POD and GST activities were significantly elevated at 0.5, 1 and 2 h in comparison to the control at 26 °C. Expression patterns were evaluated for the three antioxidant genes under high and low temperature stress. In a time course study at –4 °C, SOD, POD and GST expression peaked at 1 h and declined at 2 h of exposure. In contrast, when transcription was monitored at 35 °C, expression was lowest at 1 h and increased at 2 h. The results provide data that will be useful in deciphering the role of antioxidant enzymes in the adaptation of F. occidentalis to climate change.

Transcriptional regulation of small heat shock protein genes by heat shock factor 1 (HSF1) in Liriomyza trifolii under heat stress

Small heat shock proteins (sHSPs) function as molecular chaperones in multiple physiological processes and are active during thermal stress. sHSP expression is controlled by heat shock transcription factor (HSF); however, few studies have been conducted on HSF in agricultural pests. Liriomyza trifolii is an introduced insect pest of horticultural and vegetable crops in China. In this study, the master regulator, HSF1, was cloned and characterized from L. trifolii, and the expression levels of HSF1 and five sHSPs were studied during heat stress. HSF1 expression in L. trifolii generally decreased with rising temperatures, whereas expression of the five sHSPs showed an increasing trend that correlated with elevated temperatures. All five sHSPs and HSF1 showed an upward trend in expression with exposure to 40 ℃ without a recovery period. When a recovery period was incorporated after thermal stress, the expression patterns of HSF1 and sHSPs in L. trifolii exposed to 40 °C was significantly lower than expression with no recovery period. To elucidate potential interactions between HSF1 and sHSPs, double-stranded RNA was synthesized to knock down HSF1 in L. trifolii by RNA interference. The knockdown of HSF1 by RNAi decreased the survival rate and expression of HSP19.5, HSP20.8, and HSP21.3 during high-temperature stress. This study expands our understanding of HSF1-regulated gene expression in L. trifolii exposed to heat stress.

Transcriptomic analysis of pre-diapause larvae of Chilo suppressalis (Walker) (Lepidoptera: Pyralidae) in natural populations

Chilo suppressalis Walker is a devastating pest of rice in Asia and exhibits facultative diapause in the larval stage. Most prior experiments on diapausing and non-diapausing C. suppressalis were conducted in the laboratory. In this study, transcriptome analyses were performed on pre-diapausing larvae collected from field populations of C. suppressalis and compared to laboratory populations. Among 2674 differentially expressed genes (DEGs), 32 DEGs related to pre-diapause and 239 universally expressed genes were screened; these were primarily enriched in "neuroactive ligand-receptor interaction", "lysosome" and "glycerolipid metabolism" in KEGG pathway analysis. With respect to clusters of orthologous genes (COG), DEGs were assigned to "posttranslational modification, protein turnover, chaperones", "carbohydrate transport and metabolism", and "secondary metabolite biosynthesis, transport and catabolism" categories. Further analysis also revealed that a key "circadian clock-controlled protein" gene is sensitive to photoperiod and significantly decreased during the pre-diapause phase. Genes encoding two small heat shock proteins, hsp21.4 and hsp27.2, were significantly expressed on August 15 as compared to three other sampling times in August 2018. Eight DEGs were randomly chosen and evaluated by real-time quantitative PCR (RT-qPCR) to validate the accuracy of the transcriptome data. The expression of six DEGs (gene-evm_000752, gene-evm_006486, gene-evm_008626, gene-evm_002485, gene-evm_011981 and Chilo_suppressalis_newGene_18103) showed significant same patterns of differential expression in both the RT-qPCR and RNA-Seq analyses. This study increases our understanding of the complex physiological and molecular mechanisms involved in C. suppressalis at the pre-diapause phase.

[A predictive model based on risk factors for early mortality in patients with newly diagnosed multiple myeloma]

目的

分析影响初治多发性骨髓瘤（NDMM）患者早期死亡（EM）的因素，建立其预测模型，以期识别EM风险。

方法

回顾性分析2009年5月至2017年1月吉林大学白求恩第一医院收治的275例NDMM患者，对6个月（EM6）、12个月（EM12）及24个月（EM24）内死亡患者初诊时基线特征进行单因素分析，并根据多因素分析结果建立EM的预测模型。

结果

本研究中EM6、EM12及EM24的发生率分别是5.5%、12.7%和30.2%；最常见的死亡原因为疾病复发/进展，在EM6、EM12及EM24中分别占60.0%、77.1%及84.3%。影响EM6的因素包括经白蛋白校正的血清钙（校正钙）>2.75 mmol/L和PLT<100×10⁹/L；影响EM12的因素包括年龄>75岁、国际分期系统（ISS） Ⅲ期、修订版国际分期系统（R-ISS） Ⅲ期、校正钙>2.75 mmol/L、血清肌酐>177 µmol/L、PLT<100×10⁹/L及骨髓浆细胞比例≥60%；影响EM24的因素中，除上述影响EM12的因素外，还包括男性和染色体核型1q+。多因素分析尚未发现EM6和EM12的独立预后因素。在EM24的多因素分析中，年龄>75岁、PLT<100×10⁹/L和染色体核型1q+是EM24的独立预后因素。根据Logistic回归系数赋分：年龄>75岁：1分；PLT<100×10⁹/L：2分；染色体核型1q+：1分，建立EM24预测模型，ROC曲线下面积为0.709（95%CI 0.626~0.793）。积分≥3分的患者24个月内死亡风险是0~2分患者的26倍，积分0~4分的NDMM患者中位总生存期分别为59、41、22、17.5及16个月（P<0.001）。

结论

年龄>75岁、PLT<100×10⁹/L和染色体核型1q+为EM24的独立预后因素，依据上述变量构建的EM24预测模型有助于识别EM风险和预测生存，具有较好标准度与区分度。

Temperature affects the tolerance of Liriomyza trifolii to insecticide abamectin

The leafminer fly, Liriomyza trifolii, is an invasive pest of horticultural and vegetable crops that possesses a robust competitive ability when compared to congeneric species, especially with respect to temperature and insecticide tolerance. Abamectin, which is commonly used to control L. trifolii in the field, was selected as the target insecticide in this study. Our objective was to study the effect of abamectin and high temperature stress on L. trifolii mortality and the expression of genes encoding cytochrome P450 (CYP450s) and heat shock proteins (Hsps) by quantitative real-time reverse transcriptase PCR (qRT-PCR). When L. trifolii was exposed to abamectin followed by exposure to 40 °C (LC50 +HT40), mortality showed a significant increase, whereas exposure to 40 ℃ followed by abamectin (HT40+LC50) reduced mortality relative to abamectin or HT40 alone. Expression of three CYP450s in the CYP4 family was highest in the HT40+LC50 treatment, followed by the LC50+HT40 treatment. The expression levels of CYP18A1 (CYP18 family) were not significantly different among treatments, and CYP301A1 (CYP301 family) was only sensitive to temperature (HT40). The expression of five sHsps showed similar expression patterns and were highly responsive to the LC50+HT40 treatment, followed by the HT40 and HT40+LC50 treatments. Based on CYP450s and Hsps expression levels, our findings that suggest that L. trifolii exhibits adaptive cross-tolerance to high temperature and abamectin. This study provides a framework for selecting the most effective application time for abamectin with respect to controlling L. trifolii, which will ultimately reduce the overuse of pesticides.

High temperature stress induces expression of CYP450 genes and contributes to insecticide tolerance in Liriomyza trifolii

Liriomyza trifolii is an invasive leafminer fly that inflicts damage on many horticultural and vegetable crops. In this study, the effects of elevated temperatures on L. trifolii tolerance to insecticides abamectin (AB), monosultap (MO) and a mixture of abamectin and monosultap (AM) were firstly investigated, then five CYP450 genes (LtCYPs) were cloned, and expression patterns and NADPH cytochrome C reductase (NCR) activity in L. trifolii were compared in response to high temperature stress and insecticide exposure. Results showed elevated temperatures induced expression of LtCYP450s, the expression level of LtCYP4g1, LtCYP4g15 and LtCYP301A1 after exposed to different high temperature were significantly up-regulated compared with the control (25 °C), while there was no significant difference in LtCYP4E21 and LtCYP18A1. Under the joint high temperature and insecticide stress, the expression of LtCYP4g15, LtCYP18A1 and LtCYP301A1 was significantly higher under elevated temperatures than that of only under AB exposure. For MO and AM exposure, only 40 °C could induce the expression of LtCYP4g15, LtCYP18A1 and LtCYP301A1. In general, the LtCYPs expression pattern was correlated with increased NCR activity and decreased mortality in response to insecticide exposure under elevated temperatures. These all demonstrated that insecticide tolerance in L. trifolii could be mediated by high temperature. This study improves our understanding of L. trifolii physiology and offers a theoretical context for improved control that ultimately reduces the abuse of insecticides and decreases exposure to non-target organisms.

Comparison of morphology, development and expression patterns of hsf and hsp11.0 of Cotesia chilonis under normal and high temperature

Cotesia chilonis (Munakata) is the dominant parasitic wasp of the rice pest, Chilo suppressalis (Walker), and is a valuable parasitic wasp for the prevention and control of C. suppressalis. In this study, developmental indicators and expression of Cchsp11.0 (heat shock protein 11.0) and Cchsf (heat shock factor) were compared for C. chilonis at 27 °C and 36 °C. Developmental duration, morphology, emergence rate, and number of C. chilonis offspring were shortened at 36 °C while the ratio of females to males increased. Cchsp11.0 and Cchsf were highly expressed in the 1^st instar stage at 36 °C, and Cchsp11.0 expression gradually decreased as C. chilonis matured; Cchsf expression was not correlated with Cchsp11.0 expression. Compared with 27 °C, the expression pattern of Cchsp11.0 and Cchsf was also not consistent, and Cchsp11.0 expression increased significantly at the adult stage. In conclusion, mildly high temperatures impact growth, development and reproduction of C. chilonis and stimulate the expression of Cchsp11.0 and Cchsf, and Cchsp11.0 and Cchsf play different roles in different developmental stages of C. chilonis at normal and high temperature.

RNA Interference of Genes Encoding the Vacuolar-ATPase in Liriomyza trifolii

The leafminer fly, Liriomyza trifolii, is an invasive pest of vegetable and horticultural crops in China. In this study, a microinjection method based on dsRNA was developed for RNA interference (RNAi) in L. trifolii using genes encoding vacuolar-ATPase (V-ATPase). Expression analysis indicated that V-ATPase B and V-ATPase D were more highly expressed in L. trifolii adults than in larvae or pupae. Microinjection experiments with dsV-ATPase B and dsV-ATPase D were conducted to evaluate the efficacy of RNAi in L. trifolii adults. Expression analysis indicated that microinjection with 100 ng dsV-ATPase B or dsV-ATPase led to a significant reduction in V-ATPase transcripts as compared to that of the dsGFP control (dsRNA specific to green fluorescent protein). Furthermore, lower dsRNA concentrations were also effective in reducing the expression of target genes when delivered by microinjection. Mortality was significantly higher in dsV-ATPase B- and dsV-ATPase D-treated insects than in controls injected with dsGFP. The successful deployment of RNAi in L. trifolii will facilitate functional analyses of vital genes in this economically-important pest and may ultimately result in new control strategies.

Molecular phylogeny inferred from the mitochondrial genomes of Plecoptera with Oyamia nigribasis (Plecoptera: Perlidae)

In this study, the mitochondrial genome of the stonefly, Oyamia nigribasis Banks, 1920 (Plecoptera: Perlidae), was sequenced and compared with the mtDNA genomes of 38 other stoneflies and two Ephemerae. The O. nigribasis mitogenome is a circular 15,923 bp molecule that encodes a large, noncoding control region (CR) and 37 typical mtDNA genes; these include 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and two ribosomal RNA genes (rRNAs), respectively. Most of the PCGs initiated with ATN and terminated with TAN. The dihydrouridine (DHU) arm of tRNASer (AGN) was missing, whereas the other 21 tRNAs all exhibited the typical cloverleaf secondary structure. Stem-loop (SL) structures and tandem repeats were identified in the CR. Phylogenetic analyses using Bayesian inference and maximum likelihood were undertaken to determine relationships between stoneflies. Results indicated that the Antarctoperlaria, which contains Gripopterygidae, was absolutely separated from Arctoperlaria; this finding agrees with morphology. Finally, the overall relationships could be summarized as follows ((((Notonemouridae + Nemouridae) + Leuctridae) + (Scopuridae + (Capniidae + Taeniopterygidae))) + (((Perlodidae + Chloroperlidae) + Perlidae) + (Pteronarcyidae + (Peltoperlidae + Styloperlidae))) + ((Diamphipnoidae + Eustheniidae) + Gripopterygidae)).

Revalidation of morphological characteristics and multiplex PCR for the identification of three congener invasive Liriomyza species (Diptera: Agromyzidae) in China

Due to varietal differences, diminutive size, and similar morphological characters, it is difficult to classify and identify Liriomyza spp., a genus comprised of economically-important, highly-polyphagous insect pests. In this study, we reconfirmed the morphological characteristics of three closely-related invasive leafminers, L. trifolii, L. sativae, and L. huidobrensis. Morphological results showed that characteristics imparted by the male genitalia were the most reliable morphological features for identification. The colors exhibited by vertical setae were variable among species, and the ratio of the length of the ultimate section of vein CuA₁ divided by penultimate section also varied within species. Although the patterns of abdominal tergites were diverse among Liriomyza spp., L. trifolii exhibited a unique pattern with a yellow patch at the 5^th black visible tergite; this pattern can be profiled as a prominent characteristic for morphological identification. In order to identify the three Liriomyza spp. quickly and accurately, we developed an improved molecular identification method using multiplex PCR based on the gene encoding mitochondrial cytochrome oxidase I (COI); this method enabled direct identification based on the size of amplified products. The results of this study provide a valuable reference for the identification of Liriomyza spp., which will ultimately improve our ability to control individual species.

Comparative transcriptome analysis of three invasive leafminer flies provides insights into interspecific competition

Liriomyza spp. (Diptera: Agromyzidae) represent a group of economically-significant highly polyphagous pests of plants grown in field and greenhouse conditions. Liriomyza spp. share similar biological and morphological characteristics, and complex interspecific interactions have been documented among these species in various geographical regions. Where the displacement of one of these species by the other has been studied, no unique mechanisms have been identified as causing it. The impact of competitive factors (such as, insecticide tolerance, thermotolerance, and adaptability to cropping systems) may be unique to specific geographic regions of Liriomyza spp., but more research is needed to confirm these hypotheses. In this study, RNA-seq was used to determine the transcriptomes of three closely-related leafminers, e.g. L. sativae, L. trifolii, and L. huidobrensis. Over 20 Gb of clean reads were generated and assembled into unique transcriptomes, and 38,747 unigenes were annotated in different databases. In pairwise comparisons, L. trifolii and L. sativae had more up-regulated genes than L. huidobrensis. With respect to common differentially-expressed genes (Co-DEGs), the three leafminers exhibited distinct groups of highly-expressed gene clusters. When genes related to competitive factors were compared, expression patterns in L. trifolii and L. sativae were more closely related to each other than to L. huidobrensis. The data suggest that DEGs involved in competitive factors may play a key role in competition and displacement of leafminers. The divergent genes identified in this study will be valuable in revealing possible mechanisms of invasion, displacement and interspecific competition in Liriomyza spp.

The complete mitochondrial genome of Flavoperla biocellata Chu, 1929 (Plecoptera: Perlidae) and the phylogenetic analyses of Plecoptera

Of the roughly 400 species of Perlidae in the world, most species are widely distributed in the northern hemisphere, but a few can be found in South Africa and South America. There are only five species in the genus Flavoperla of the family Perlidae in China. To gain a better understanding of the architecture and evolution of mitochondrial genome in Flavoperla, the entire mitochondrial genome (mitogenome) of a Chinese Flavoperla biocellata Chu, 1929 from family Perlidae (Insecta: Plecoptera) was sequenced. The 15,805-bp long mitochondrial genome of F. biocellata contained 37 genes, including 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs) and a putative control region (CR). The gene arrangement of F. biocellata was identical with that of other stoneflies and with the fly Drosophila yakuba. Most PCGs of F. biocellata used the standard ATN start codons and complete TAN termination codons. Twenty-one of the 22 tRNA genes exhibited cloverleaf secondary structures, but the dihydrouridine (DHU) arm of trnSer (AGN) was completely reduced. Phylogenetic analyses with both Bayesian inference (BI) and maximum likelihood methods (ML) generated similar topology, both supporting the monophyly of all stonefly families and the infraorder Systellognatha. The phylogenetic analysis based on mitochondrial genomic data from 30 stonefly species recovered a well-supported tree resolving higher-level relationships within Plecoptera. The northern hemisphere suborder Arctoperlaria divided into two groups, Euholognatha and Systellognatha. The southern hemisphere suborder Antarctoperlaria formed two clades: Eustheniidae+Diamphipnoidae and Austroperlidae+ Gripopterygidae; consistent with relationships proposed based on morphology. The final relationships within Plecoptera were recovered as (((Perlidae+(Perlodidae+Chloroperlidae))+(Pteronarcyidae+(Peltoperlidae+Styloperlidae))) +(Taeniopterygidae+(Capniidae+(Nemouridae+Notonemouridae))))+ (Gripopterygoidae+Eusthenioidae).

Characterization of an inducible HSP70 gene in Chilo suppressalis and expression in response to environmental and biological stress

The highly conserved heat shock protein 70 (HSP70) contributes to survival at a cellular level and greatly enhances stress tolerance in many organisms. In this study, we isolate and characterize Cshsp702, which encodes an inducible form of HSP70 in the rice stem borer, Chilo suppressalis. Cshsp702 does not contain introns; the translational product is comprised of 629 amino acids with an isoelectric point of 5.69. Real-time quantitative PCR revealed that Cshsp702 was expressed at maximal levels in hemocytes and was minimally expressed in the midgut. Expression of Cshsp702 in response to a range of temperatures (-11 to 43 °C) indicated significant induction by extreme cold and hot temperatures, with maximum expression after 2 h at 42 °C. The induction of Cshsp702 in response to the endoparasite Cotesia chilonis was also studied; interestingly, Cshsp702 expression in C. suppressalis was significantly induced at 24 h and 5 days, which correspond to predicted times of C. chilonis feeding and growth, respectively. The potential induction of Cshsp702 as an inflammatory response due to parasitic stress is discussed. In conclusion, Cshsp702 is induced in response to both environmental and biotic stress and plays an important role in the physiological adaptation of C. suppressalis.

Selection of valid reference genes for quantitative real-time PCR in Cotesia chilonis (Hymenoptera: Braconidae) exposed to different temperatures

In quantitative real-time PCR (qRT-PCR), data are normalized using reference genes, which helps to control for internal differences and reduce error among samples. In this study, the expression profiles of eight candidate housekeeping genes, 18S ribosomal (18S rRNA), elongation factor (EF1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), ribosomal protein L10 (RPL10), ribosomal protein L17 (RPL17), histone 3 (H3), arginine kinase (AK), amd β-Actin (ACTB), were evaluated in the parasitic wasp Cotesia chilonis in response to different temperatures. Specifically, the performance and stabilities of these genes were compared in adult wasps maintained in a growth condition at 27°C (normal storage conditions) and in adults obtained from pupae refrigerated at 4°C for five days (cold storage conditions). Data were analyzed using the ΔCt method, BestKeeper, NormFinder, and geNorm. The optimal numbers and stabilities of reference genes varied between the two temperature treatments (27°C and 4°C). In samples stored at normal developmental temperature (27°C), the requirement for normalization in response to low temperature exposures was three genes (18S, H3, AK), whereas normalization in response to high temperature exposures required only two reference genes (GAPDH, ACTB). In samples stored at cold temperature (4°C), for low temperature exposures two reference genes (RPL17, RPL10) were required for standardization, while following high temperature exposures three reference genes (18S, H3, ACTB) were needed. This study strengthens understanding of the selection of reference genes before qRT-PCR analysis in C. chilonis. The reference genes identified here will facilitate further investigations of the biological characteristics of this important parasitoid.

Molecular Cloning and Characterization of Small Heat Shock Protein Genes in the Invasive Leaf Miner Fly, Liriomyza trifolii

Small heat shock proteins (sHSPs) comprise numerous proteins with diverse structure and function. As molecular chaperones, they play essential roles in various biological processes, especially under thermal stresses. In this study, we identified three sHSP-encoding genes, LtHSP19.5, LtHSP20.8 and LtHSP21.7b from Liriomyza trifolii, an important insect pest of ornamental and vegetable crops worldwide. Putative proteins encoded by these genes all contain a conserved α-crystallin domain that is typical of the sHSP family. Their expression patterns during temperature stresses and at different insect development stages were studied by reverse-transcription quantitative PCR (RT-qPCR). In addition, the expression patterns were compared with those of LtHSP21.3 and LtHSP21.7, two previously published sHSPs. When pupae were exposed to temperatures ranging from −20 to 45 °C for 1 h, all LtsHSPs were strongly induced by either heat or cold stresses, but the magnitude was lower under the low temperature range than high temperatures. Developmentally regulated differential expression was also detected, with pupae and prepupae featuring the highest expression of sHSPs. Results suggest that LtsHSPs play a role in the development of the invasive leaf miner fly and may facilitate insect adaptation to climate change.

Cloning of a new HSP70 gene from western flowerthrips, Frankliniella occidentalis, and expression patterns during thermal stress

Frankliniella occidentalis (Pergande) is an invasive pest that endangers a wide variety of horticultural and agronomic crops. HSP70 is the most important member of the heat shock protein (HSP) family and plays an important role in insect thermal tolerance. In this study, a new gene encoding HSP70 from F. occidentalis, Fohsp706, was selected from the F. occidentalis transcriptome exposed to thermal stress (40 °C) and cloned by RT-PCR and RACE. Further characterization indicated that Fohsp706 localizes to the cytoplasm and does not contain introns. Quantitative real-time reverse transcriptase PCR indicated that Fohsp706 expression was significantly up-regulated by thermal stress; furthermore, there were significant differences in Fohsp706 expression in adults and second instar nymphs after heat stress. Our results indicated that Fohsp706 contributes to thermotolerance in F. occidentalis and provides another example of how this pest adapts to unfavorable environmental conditions.

Characterization of genes encoding small heat shock proteins from Bemisia tabaci and expression under thermal stress

Small heat shock proteins (sHSPs) are probably the most diverse in structure and function among the various super-families of stress proteins, and they play essential roles in various biological processes. The sweet potato whitefly, Bemisia tabaci (Gennadius), feeds in the phloem, transmits several plant viruses, and is an important pest on cotton, vegetables and ornamentals. In this research, we isolated and characterized three α-crystallin/sHSP family genes (Bthsp19.5, Bthsp19.2, and Bthsp21.3) from Bemisia tabaci. The three cDNAs encoded proteins of 171, 169, and 189 amino acids with calculated molecular weights of 19.5, 19.2, and 21.3 kDa and isoelectric points of 6.1, 6.2, and 6.0, respectively. The deduced amino acid sequences of the three genes showed strong similarity to sHSPs identified in Hemiptera and Thysanoptera insects species. All three sHSPs genes from Bemisia tabaci lacked introns. Quantitative real-time PCR analyses revealed that the three BtsHSPs genes were significantly up-regulated in Bemisia tabaci adults and pupae during high temperature stress (39, 41, 43, and 45 °C) but not in response to cold temperature stress (-6, -8, -10, and -12 °C). The expression levels of Bthsp19.2 and Bthsp21.3 in pupae was higher than adults in response to heat stress, while the expression level of Bthsp19.5 in adults was higher than pupae. In conclusion, this research results show that the sHSP genes of Bemisia tabaci had shown differential expression changes under thermal stress.

A Novel Aquaporin 12-like Protein from Chilo suppressalis: Characterization and Functional Analysis

Aquaporins (AQPs), which are members of the major intrinsic protein (MIP) family, play an important role in the transport of water and other small, uncharged solutes across membranes. In this study, we identified gene encoding two aquaporin 12-like (AQP12L) proteins, CsAqp12L_v1 and CsAqp12L_v2, from Chilo suppressalis, a serious rice pest in Asia. Phylogenetic analysis indicated that CsAQP12L_V1 and CsAQP12L_V2 were grouped in a well-supported cluster that included other members of Lepidoptera. The two proteins are almost identical, except that CsAQP12L_V1 lacks 34 amino acids that are present in CsAQP12L_V2 at site 217. The qRT-PCR indicated that both CsAqp12L and CsAqp12L_v2 were expressed in heads, epidermis, foregut, midgut, and hindguts, with the highest level of expression in hindguts, heads, and epidermis. Expression of CsAqp12L and CsAqp12L_v2 was detected in all life stages and both sexes and was highest in first instar larvae and lowest in eggs. Expression of CsAqp12L and CsAqp12L_v2 was not significantly altered by exposure to brief changes in temperature. There were no significant differences in the third instar larvae, male and female pupae, and female adults in response to adverse humidity. However, the mRNA level of CsAqp12L in the fifth instar larvae and CsAqp12L_v2 in male adults was induced significantly by low humidity, respectively. Moreover, Xenopus oocytes injected with cRNAs of CsAQP12L_V1 and CsAQP12L_V2 showed no significant changes in permeability to water, glycerol, trehalose, or urea. The two CsAQP12L variants likely localize to an intracellular location in C. suppressalis and may respond to novel stimuli.

Review of the rare and little-known Chinese species of the family Taeniopterygidae (Plecoptera), with description of two new species of Kyphopteryx

The species of the family Taeniopterygidae (Plecoptera) are reviewed from China. Two new Kyphopteryx species, K. yangi sp. nov. and K. coniformis sp. nov. are described and illustrated from Yunnan Province of southwestern China. Additionally, a provisional key to the males of Taeniopterygidae known from China is provided.

Diversity and evolution of the endosymbionts of Bemisia tabaci in China

The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex, including members that are pests of global importance. This study presents a screening of B. tabaci species in China for infection by the primary endosymbiont, Portiera aleyrodidarum, and two secondary endosymbionts, Arsenophonus and Cardinium. The results showed that P. aleyrodidarum was detected in all B. tabaci individuals, while Arsenophonus was abundant in indigenous species of B. tabaci Asia II 1, Asia II 3, and China 1 but absent in the invasive species, Middle East-Asia Minor 1 (MEAM1); Cardinium presented in the Mediterranean (MED), Asia II 1 and Asia II 3 species but was rarely detected in the MEAM1 and China 1 species. Moreover, phylogenetic analyses revealed that the P. aleyrodidarum and mitochondrial cytochrome oxidase 1 (mtCO1) phylograms were similar and corresponding with the five distinct cryptic species clades to some extent, probably indicating an ancient infection followed by vertical transmission and subsequent co-evolutionary diversification. In contrast, the phylogenetic trees of Arsenophonus and Cardinium were incongruent with the mtCO1 phylogram, potentially indicating horizontal transmission in B. tabaci cryptic species complex. Taken together, our study showed the distinct infection status of endosymbionts in invasive and indigenous whiteflies; we also most likely indicated the co-evolution of primary endosymbiont and its host as well as the potential horizontal transfer of secondary endosymbionts.

Comparative analysis of the Liriomyza chinensis mitochondrial genome with other Agromyzids reveals conserved genome features

Liriomyza chinensis is a serious pest of onions in many countries, especially in East Asia. We sequenced the complete mitochondrial genome of this species and compared it with five other Agromyzidae species. The L. chinensis mitogenome is a double-stranded 16,175 bp circular molecule with an A + T content of 78.3%. It contains 37 genes and a control region as do the sequenced Liriomyza species. The mitogenomes of L. chinensis and other Agromyzidae species showed a clear bias in nucleotide composition with a positive AT-skew. Most PCGs used standard ATN as start codons, and TAN as termination codons. The tRNAs exhibited the typical clover-leaf structure, except for tRNASer^(AGN) and the two rRNA genes are conserved with those of other Agromyzids. The L. chinensis mitogenome control region included several conserved regions, including a poly-T, two (TA)n and one poly-A stretch, which are considered important replication and transcription. The 13 PCGs were used to study the phylogeny of L. chinensis and five related Agromyzids. Analysis by maximum likelihood, Bayesian inference and genetic distance suggest congruent phylogenetic relationships in Liriomyza spp. and provide a useful supplement to taxonomic classification by morphology.