Genetic differentiation and phylogeography of Erythroneurini (Hemiptera, Cicadellidae, Typhlocybinae) in the southwestern karst area of China.

Erythroneurini is the largest tribe of the microleafhopper subfamily Typhlocybinae. Most prior research on this tribe has focused on traditional classification, phylogeny, and control of agricultural pests, and the phylogeography of the group remains poorly understood. In this study, the mitochondrial genomes of 10 erythroneurine species were sequenced, and sequences of four genes were obtained for 12 geographical populations of Seriana bacilla. The new sequence data were combined with previously available mitochondrial DNA sequence data and analyzed using Bayesian and Maximum-Likelihood-based phylogenetic methods to elucidate relationships among genera and species and estimate divergence times. Seriana was shown to be derived from within Empoascanara. Phylogeographic and population genetic analysis of the endemic Chinese species Seriana bacilla suggest that the species diverged about 54.85 Mya (95% HPD: 20.76-66.23 million years) in the Paleogene period and that population divergence occurred within the last 14 million years. Ancestral area reconstruction indicates that Seriana bacilla may have originated in the central region of Guizhou, and geographical barriers are the main factors affecting gene flow among populations. Ecological niche modeling using the MaxEnt model suggests that the distribution of the species was more restricted in the past but is likely to expand in the future years 2050 and 2070.

Two new species of Erythroneurini (Hemiptera, Cicadellidae, Typhlocybinae) from southern China based on morphology and complete mitogenomes.

Erythroneurine leafhoppers (Hemiptera, Cicadellidae, Typhlocybinae, Erythroneurini) are utilized to resolve the relationship between the four erythroneurine leafhopper (Hemiptera, Cicadellidae, Typhlocybinae, Erythroneurini): Arboridia (Arboridia) rongchangensis sp. nov., Thaia (Thaia) jiulongensis sp. nov., Mitjaevia bifurcata Luo, Song & Song, 2021 and Mitjaevia diana Luo, Song & Song, 2021, the two new species are described and illustrated. The mitochondrial gene sequences of these four species were determined to update the mitochondrial genome database of Erythroneurini. The mitochondrial genomes of four species shared high parallelism in nucleotide composition, base composition and gene order, comprising 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs) and an AT control region, which was consistent with majority of species in Cicadellidae; all genes revealed common trait of a positive AT skew and negative GC skew. The mitogenomes of four species were ultra-conservative in structure, and which isanalogous to that of others in size and A + T content. Phylogenetic trees based on the mitogenome data of these species and another 24 species were built employing the maximum likelihood and Bayesian inference methods. The results indicated that the four species belong to the tribe Erythroneurini, M. diana is the sister-group relationship of M. protuberanta + M. bifurcata. The two species Arboridia (Arboridia) rongchangensis sp. nov. and Thaia (Thaia) jiulongensis sp. nov. also have a relatively close genetic relationship with the genus Mitjaevia.

Climate change may drive the distribution of tribe Zyginelline pests in China and the Indo-China Peninsula to shift towards higher latitude river-mountain systems.

BACKGROUND: Tribe Zyginelline leafhoppers can transmit plant viruses and are important pests that affect agriculture, forestry, and animal husbandry, causing serious economic losses. The potential distribution patterns of Zyginellini will change under climate change. Therefore, the best-performing random forest and maximum entropy models among 12 commonly used ecological niche models, alongside an ensemble model, were selected to predict the changes in habitat suitability distribution of Zyginellini under current and future climate scenarios [represented by two shared socio-economic pathways (SSPs), namely SSP126 and SSP585, for three periods (2050s, 2070s, and 2090s)] in China and the Indo-China Peninsula for the first time. RESULTS: The results revealed that the distribution of Zyginellini was mainly dominated by minimum temperature of coldest month. Under current and future climate scenarios, Zyginellini was mostly distributed southeast of the 400 mm equivalent precipitation line in China, and Vietnam. Under the future SSP126 scenario, the alert areas will mainly be concentrated in Hunan, Jiangxi, Zhejiang, Anhui, and Hebei in China, alongside Myanmar and Thailand in the Indo-China Peninsula. Meanwhile, in the SSP585 scenario, the alert areas in China will increase, whereas there will be little change in the Indo-China Peninsula. Interestingly, from the current to the future, the cores of Zyginelline distribution occurred around rivers and mountains, and shifted from Guizhou along the Yuanjiang River system to higher latitudes in Hunan. CONCLUSION: Zyginellini prefers higher latitude river-mountain systems under climate change. Our results will contribute to effective pest control strategies and biogeographical research for Zyginellini alongside other Cicadellidae insects. © 2023 Society of Chemical Industry.

Effects of habitats in typical karst areas of Guizhou on ultrastructural morphology of Typhlocybinae.

Biology and the environment are inextricably linked. Insects are intricately linked to their habitats as part of the ecosystem. In this study, scanning electron microscopy (SEM) observations showed two sensilla chaetica, several sensilla trichodea, and at least one sensilla basiconicum on the antennae of typhlocybine insects. There were no sensilla on the labrum; however, the surface morphology was different. There were more sensilla trichodea on the surface, mostly symmetrically distributed along the labial groove, and there was little difference in the structure of the stylet fascicle. The correlation between the sensilla number on the body surface of typhlocybine insects and environmental factors in the 3 study areas was as follows: Huajiang > Bijie > Shibing, which is consistent with the classification of rocky desertification grade; that is, the higher the rocky desertification grade, the greater the sensilla number on leafhoppers affected by the environment. The correlation between the number of leafhoppers and environmental factors in the 3 months was as follows: end of September > end of May > end of July, which was consistent with the changing temperature trends. The results of this study enrich our knowledge of the morphological characteristics of leafhoppers and explore the potential value of insect surface ultra-morphology for use by humans.

Fumigant activity and transcriptomic analysis of two plant essential oils against the tea green leafhopper, Empoasca onukii Matsuda.

Introduction: The tea green leafhopper, Empoasca (Matsumurasca) onukii Matsuda, R., 1952 (Hemiptera: Cicadellidae), is currently one of the most devastating pests in the Chinese tea industry. The long-term use of chemical pesticides has a negative impact on human health, impeding the healthy and sustainable development of the tea industry in this region. Therefore, there is a need for non-chemical insecticides to control E. onukii in tea plants. The essential oils from plants have been identified for their potential insecticidal ability; however, there is a lack of knowledge regarding the effect of plant essential oils on E. onukii and its gene expression. Methods: In order to address these knowledge gaps, the components of Pogostemon cablin and Cinnamomum camphora essential oils were analyzed in the present study using gas chromatography-mass spectrometry. The fumigation toxicity of two essential oils on E. onukii was tested using sealed conical flasks. In addition, We performed comparative transcriptome analyses of E. onukii treated with or without P. cablin essential oil. Results: The 36-h lethal concentration (LC50) values for E. onukii treated with P. cablin and C. camphora essential oils were 0.474 and 1.204 µL mL-1 respectively. Both essential oils exhibited the potential to control E. onukii, but the fumigation activity of P. cablin essential oil was more effective. A total of 2,309 differentially expressed genes were obtained by transcriptome sequencing of E. onukii treated with P. cablin essential oil. Conclusion: Many of differentially expressed genes were found to contain detoxifification genes, indicating that these families may have played an important role when E. onukii was exposed to essential oil stress. We also found differential expression of genes related to redox-related gene families, suggesting the upregulation of genes associated with possible development of drug and stress resistance. This work offers new insights for the prevention and management of E. onukii in the future.

Phylogenetic Analysis of Two New Mitochondrial Genomes of Singapora shinshana and Seriana bacilla from the Karst Region of Southwest China.

Leafhoppers have been identified as a serious threat to different plants. To explore the characteristics of mitogenomes and reveal the phylogenetic positions of two species in the Typhlocybinae, complete mitogenomes of Singapora shinshana and Seriana bacilla were sequenced and annotated for the first time with lengths of 15,402 bp and 15,383 bp, respectively. The two mitogenomes contained 13 PCGs, 22 tRNA genes and 2 rRNA genes. The genome content, gene order, nucleotide composition, codon usage and amino acid composition are similar to those of other typical mitogenomes of Typhlocybinae. All 13 PCGs started with ATN codons, except for atp8 (TTA) and nad5 (TTG). All tRNAs were folded into a typical cloverleaf secondary structure, except for tRNA-Ser1 and tRNA-Val. Moreover, phylogenetic trees were constructed and analyzed based on all the PCGs from 42 mitogenomes using maximum likelihood (ML) and Bayesian inference (BI) methods. The results supported that eleven subfamilies are all monophyletic groups, S. shinshana and S. bacilla are members of Erythroneurini, but S. shinshana and the genus Empoascanara have a very close relationship with ((((Empoascanara sipra+ Empoascanara wengangensis) + Empoascanara dwalata) + Empoascanara gracilis) + S. shinshana), and S. bacilla is closely related to the genus Mitjaevia ((Mitjaevia dworakowskae + Mitjaevia shibingensis) + S. bacilla). These results provide valuable information for future study of evolutionary relationships in Typhlocybinae.

The role of insect intestinal microbes in controlling of Empoasca onukii Matsuda (Hemiptera: Cicadellidae) pest infestations in the production of tea garden: a review.

Pests like the phytophagous bug Empoasca onukii Matsuda frequently harm tea plants. The harm this insect does to agricultural and environmentally sensitive places is extremely harmful since physical and chemical prevention and control are still the primary methods of handling it. Therefore, it is important to develop pest management strategies. Recent research has demonstrated that pathogenic fungus and the gut microbiota interact to induce host and death, and that the gut microbiota, which has a dramatic effect on the host, can engage in pest control. The advancement of genome editing technologies is also new to the field of pest management. The diversity, function, and research methodologies of insect gut microbiota are summarized in this work, and discusses E. onukii Matsuda control options as well as the importance of insect gut microbiome in pest management. In comparison to traditional pesticides and physical prevention and control, the interaction between pathogenic fungi represented by Beauveria bassiana and intestinal microorganisms, as well as their participation in pest management, causes physiological stress on the host, which meets the new requirements of modern agricultural green development and has a protective effect on habitat fragmentation areas (Karst region). Exploring additional harmful fungus for pest management and fully using the specific traits of insect gut microbiota to achieve "killing insects with bacteria" would be a promising technique from this standpoint.

Complete mitochondrial genome of Kusala populi (Song, Li & Xiong, 2011) (Hemiptera, Cicadellidae, Typhlocybinae) from Karst area, Southwest China.

In this study, we sequenced and reported the complete mitochondrial genomes of Kusala populi for the first time. The complete mitochondrial genome was registered in GenBank with accession number NC_064377 as the first complete mitogenome of the genus Kusala. The circular mitochondrial genome length is 15,402 bp, with nucleotide composition A (41.8%), C (11.4%), G (9.2%), T (37.6%), A + T (79.4%), and C + G (20.6%), comprising 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a D-loop region. All protein-coding genes were encoded by the H-strand, except for 4 genes (nad5, nad4, nad4L, nad1). 8 tRNA genes (tRNA-Gln, tRNA-Cys, tRNA-Tyr, tRNA-Phe, tRNA-His, tRNA-Pro, tRNA-Leu, tRNA-Val) and 2 rRNA genes (16S, 12S) were encoded in the L-strand. Phylogenetic analysis indicated that the newly sequenced species had a close relationship with Mitjaevia, another widespread Old-World genus of Erythroneurini.

Two new species of Erythroneurini from China (Hemiptera: Cicadellidae: Typhlocybinae).

In the present paper, two new erythroneurine species from Yunnan province, China, Arboridia (Arboridia) jinghongensis sp. nov. and Empoascanara (Empoascanara) lancanga sp. nov., are described and illustrated.

Two new species of the genus Kapsa Dworakowska from the karst area of Southwest China (Hemiptera: Cicadellidae: Typhlocybinae).

The leafhopper genus Kapsa Dworakowska, 1972 contains 32 species, mainly known from the Oriental Realm. Two new species collected from Huajiang Town, Guizhou Province, China are described and illustrated, Kapsa huajiangensis sp. n. and Kapsa uniaxialis sp. n. A key to distinguish all the Chinese species of the nominotypical subgenus is given.

Effects of Habitat Fragmentation on the Population Structure and Genetic Diversity of Erythroneurini in the Typical Karst Rocky Ecosystem, Southwest China.

Karst rocky desertification is one of the main causes of habitat fragmentation in Southwest China. Guizhou Province is located in the center of the karst area in southern China and is a typical karst ecological environment fragile area. Many studies have shown that habitat fragmentation is the main factor leading to the loss of biodiversity and species extinction, and it is also one of the important factors that threaten the survival of natural organisms. This study initially explored the habitat fragmentation degree, species diversity, and genetic diversity of leafhoppers in three typical karst areas in Guizhou. The study was combined with the general situation of the study area, understanding the main factors affecting habitat fragmentation, and putting forward reasonable protection suggestions for species resources. Based on satellite imagery, field survey collection, molecular sequencing data, and related index measurement methods, we measured the habitat fragmentation degree, species diversity index, and genetic diversity index of Erythroneurine leafhoppers of Shibing Yuntai Mountain Nature Reserve, Bijie Salaxi Demonstration Zone, Zhenfeng-Huajiang Demonstration Zone. Moreover, we compared the differences in the three study areas, carried out correlation analysis with relevant environmental factors, and discussed the main factors that formed the results. The results of the study show that the species diversity and genetic diversity of Erythroneurine leafhoppers in the study areas are affected by habitat fragmentation, and the weaker the degree of habitat fragmentation in the region, the higher the species diversity and genetic diversity, which is specifically manifested in species, quantity, and gene-flow. Understanding the status of biodiversity in karst areas is conducive to the sustainable development of biological resources. In order to better protect the diversity of such insects and their host plants and other biological diversity, combined with the background of the research area, we propose corresponding protection measures for reference.

Insulin-Like ILP2 Regulates Trehalose Metabolism to Tolerate Hypoxia/Hypercapnia in Tribolium castaneum.

RNAi was used to downregulate the expression of insulin-like peptides (ILP2), with air-modulation, and high-concentration CO2 stress, in the larvae of Tribolium castaneum. We assessed the changes in carbohydrate-related content, trehalase activity, and the expression levels of trehalose pathway genes. And pupation, adult emergence, pupation rate, and mortality were assessed. There was a significant change in the expression of ILPs in T. castaneum, at a certain concentration of CO2. ILP2 RNAi did not alter the trehalose content significantly, however, the glycogen and glucose content increased significantly. High-concentration CO2 stress altered the trehalose content and reduced the glycogen and glucose content. The expression levels of TPS and TRE2 were up-regulated by hypoxia/hypercapnia and dsILP2 combination, with the increase of CO2 concentration, other trehalase genes begin to respond successively. ILP2 knockout raised the mortality and reduced the pupation rate and eclosion rate in CO2. Understanding the insulin pathway responses to hypoxic stress induced by a high concentration of CO2 would further elucidate the mechanisms underlying trehalose metabolism in insects.

Two new species of the genus Anufrievia Dworakowska (Hemiptera, Cicadellidae, Typhlocybinae) from karst region of southwest China.

Background: The leafhopper genus Anufrievia was established by Dworakowska with A.rolikae Dworakowska as its type species. They are widely distributed in China, North Korea, South Korea, Japan, Nepal, India, Indonesia, Thailand and Vietnam. New information: Two new species, A.ventricosa sp. nov. and A.unianxialis sp. nov., found in the karst area of Guanling and Shibing City, Guizhou Province, China are described and illustrated. The key to the identification of the specie of this genus is given.

Three new species of the leafhopper genus Mitjaevia Dworakowska from Karst areas in Southwest China (Hemiptera, Cicadellidae, Typhlocybinae).

Three new species of the leafhopper genus MitjaeviaDworakowska 1970, M.bijiensis sp. nov., M.solitaria sp. nov., and M.salaxia sp. nov., are described from the Karst region of Southwest China. Specimens studied were taken by sweep net. Morphological descriptions, depictions of habitus and illustrations of male terminalia are provided. A key and checklist to known species occurring in China are given.

Comparative morphology of part of the integumental fine structure of two Erythroneurine species: Singaporashinshana (Matsumura, 1932) and Empoascanarasipra Dworakowska, 1980 (Hemiptera, Cicadellidae, Typhlocybinae).

This study describes the fine structure of the mouthparts, antennae, forewings, and brochosomes of two leafhopper species belonging to the typhlocybine tribe Erythroneurini collected from the Karst area of Guizhou Province, southern China: Singaporashinshana, which prefers woody dicot hosts, and Empoascanarasipra, which feeds on grasses. As in other leafhoppers, the piercing-sucking mouthparts consist of a conical labrum, a cylindrical three-segmented labium, and a slender stylet fascicle. The labrum of both species has no sensilla and the labium has several common types of sensilla, but the two species differ in the numbers, types, and distribution of sensilla and in other aspects of the surface sculpture of the mouthparts. The stylet fascicle has distinctive dentition on both the maxillary and mandibular stylets. The antennae of the two species differ in several respects, including the sensilla and sculpture of the scape, pedicel, and flagellum, as well as the degree of sub-segmentation of the flagellum. Except for the variable scaly structure and rounded protrusions on the surface of S.shinshana, the fine structure of the forewing surfaces of the two species are similar to those of other leafhoppers. Only small spherical brochosomes were found on the body surface of S.shinshana and E.sipra. Similar studies of additional erythroneurine species are needed to determine whether differences in mouthpart and antennal fine structure may reflect adaptation to different host plant.

Two new species of the genus Tautoneura Anufriev from Karst area in Southwest China (Hemiptera: Cicadellidae: Typhlocybinae).

Two new species of the leafhopper genus Tautoneura Anufriev from Karst areas in Southwest China are described and illustrated, Tautoneura aureomarginalis sp. nov. and Tautoneura lageniformis sp. nov. A key to distinguish the Chinese species of the genus is given.

Characterization of the morphology and complete mitochondrial genomes of Eupteryx minusula and Eupteryx gracilirama (Hemiptera: Cicadellidae: Typhlocybinae) from Karst area, Southwest China.

BACKGROUND: The hemipteran insect family Cicadellidae (leafhoppers) includes >2,600 valid genera and >22,000 valid species worldwide, including >2,000 species in China. Typhlocybinae, second largest subfamilies of Cicadellidae, is widely distributed in the six major zoogeographic regions of the world, including >4,000 species worldwide and >1,000 species in China. Previously, morphological analysis are often effective to the way of taxonomy, but it did not combine with molecular biology. Therefore, morphology and mitochondrial genomes (mitogenomes) of two leafhopper species, Eupteryx (Eupteryx) minuscula Lindberg, 1929 and Eupteryx (Stacla) gracilirama Hou, Zhang & Huang, 2016 were studied and analyzed. This study analyzed the morphological and molecular characteristics of the two leafhoppers, and showed whether the results of the two identifications were consistent. METHODS: Based on the method of comparison, mitogenomes and morphology were analyzed to prove the relationship between the two leafhoppers. RESULTS: Although two focal species are classified in two different subgenera of the same genus, they still share many morphological features, such as the moderately produced crown fore margin; the milky yellow apical part of scutellum; the pronotum, basal triangles of scutellum, and forewing are dark with several colorless patches on the surface; the light yellow face, without any spots or stripes, and so on. The circular mitogenomes are 16,944 bp long in E. minuscula (GenBank: MN910279) and 17,173 bp long in E. gracilirama (GenBank: MT594485). All of the protein-coding genes are starting with ATN, except for some in mitogenome, which has a single T or TAN as a stop codon. All tRNAs have the typical cloverleaf-shaped structure except for trnS1 (AGN) (E. minuscula) which has a reduced DHU arm. Moreover, these two mitogenomes have trnR with an unpaired base in the acceptor stem. The phylogenetic relationships between E. minuscula and E. gracilirama in respect to related lineages were reconstructed using Maximum likelihood and Maximum parsimony analyses. DISCUSSION: The result showed that the tribe Typhlocybini is a sister to the tribes Erythroneurini and Empoascini, and five genera, Bolanusoides, Typhlocyba, Eupteryx, Zyginella and Limassolla are forming a single clade. E. minuscula and E. gracilirama are clustered together, supporting the monophyly of the genus Eupteryx. The above conclusions are consistent with the traditional classification of the subfamily.

Two new species of the leafhopper genus Mitjaevia Dworakowska from China (Hemiptera, Cicadellidae, Typhlocybinae).

BACKGROUND: The leafhopper genus Mitjaevia Dworakowska,1970 includes 19 species worldwide, nine species are known in China and is widely distributed in Palaearctic and Oriental Regions. NEW INFORMATION: Two new species from Guizhou Province, China are described within the genus Mitjaevia Dworakowska, 1970 (Hemiptera: Cicadellidae: Typhlocybinae). A key to the species of the genus is provided and the female valvulae are described and figured.

Two new species of the genus Arboridia Zachvatkin from China (Hemiptera: Cicadellidae: Typhlocybinae).

Two new species of the leafhopper tribe Erythroneurini from Guizhou province, China, Arboridia (Arboridia) huajiangensis sp. nov. and Arboridia (Arborifera) changlingensis sp. nov. are described and illustrated. The ovipositor of A. huajiangensis sp. nov. is photographed and described. A key distinguishing all known species of the genus in China is provided.

Two new species of Erythroneurini from China (Hemiptera, Cicadellidae, Typhlocybinae).

BACKGROUND: The leafhopper genus Empoascanara Distant, 1918 encompasses 81 species, most of which are distributed in Afrotropical, Oriental and Australian Realm. The leafhopper genus Kapsa Dworakowska, 1972 encompasses 23 species, mainly known from the Oriental and Australian Realms. NEW INFORMATION: Two new species of the leafhopper tribe Erythroneurini from Guizhou Province, China, Empoascanaradichotomus sp. nov. and Kapsasinuose sp. nov. are described and illustrated. Identification keys to the males of the genera Empoascanara and Kapsa in China are proposed.