Acta Entomologica Sinica

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Research and applications of genetic pest management techniques

SUN Hao, GAO Cong-Fen, WU Shun-Fan

Acta Entomologica Sinica 2024, 67 (3): 404-421. DOI: 10.16380/j.kcxb.2024.03.011

Abstract （608）

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Insect vectors cause significant economic losses and human casualties worldwide each year by transmitting parasites and viruses such as malaria, Zika virus, and dengue. Agricultural pests cause huge losses of crop yield every year and seriously threaten global food security. However, the current control methods based on chemical agents are insufficient to completely control the occurrence and damage of pests. At the same time, the use of chemical pesticides will induce resistance and result in environmental pollution and pesticide residues, etc. Therefore, there is an urgent need to develop new pest control strategies in production. In recent years, with the development of genome sequencing and gene editing techniques, the genetic control technology for the target pest population and their specific target genes has been rapidly developed. Compared with traditional pest control methods such as chemical control, genetic control strategies for pests have the advantages of species specificity, environmental friendliness, and efficient control. In this article, we reviewed several widely studied genetic control techniques for pests, including sterile insect technique (SIT), release of insects carrying a dominant lethal (RIDL), and gene drive (GD) technology. Finally, we presented several prospects for the research of genetic control technology for pests and its application in agricultural pest control: (1) to establish stable and efficient genetic manipulation systems; (2) to identify efficient promoters in germ cells or other tissues to improve the efficiency of gene editing or gene transformation; and (3) to elucidate the sex determination pathway of pests and excavate the key genes involved in the reproductive development of pests.

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Insect symbionts: Research progresses and prospects

LUAN Jun-Bo, WANG Si-Bao

Acta Entomologica Sinica 2023, 66 (10): 1271-1281. DOI: 10.16380/j.kcxb.2023.10.001

Abstract （607）

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Insect symbionts are microorganisms that establish enduring and sustained associations with insect hosts. These microorganisms inhabit the body surface, gut, hemocoel, or intracellular cells of insects, participating in the regulation of various physiological functions of their host insects. Research on insect-symbiont interactions involves multidisciplinary collaboration. In-depth exploration of the functions of insect symbionts and their interactions with hosts not only advances our understanding of fundamental mechanisms in the life sciences but also introduces innovative perspectives and methods for pest management, vector-borne disease control, and optimal utilization of beneficial insects. In recent years, Chinese researchers have made noteworthy progress in the insect microbiome and got significant achievements in many research directions. In this article, we provided an overview of the most recent research progress in insect symbionts, introduced the main contents of this special issue, and proposed three noteworthy research directions: (1) the functions of insect intracellular symbionts; (2) the mechanisms by which insects regulate the abundance and transmission of symbionts; and (3) genetic modification and application of insect symbionts.

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Toxicity and risk assessment of the formulations of seven neonicotinoid insecticides to Coccinella septempunctata (Coleoptera: Coccinellidae)

YOU Yong, ZHAO Jian-Wei, TANG Bao-Hua, ZENG Zhao-Hua, LUO Feng-Qiu, CHEN Yi-Xin, YANG Feng-Hua, XIE Miao, LIU Xin-Gang, WEI Hui

Acta Entomologica Sinica 2023, 66 (6): 759-769. DOI: 10.16380/j.kcxb.2023.06.004

Abstract （431）

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【Aim】To evaluate the toxicity and ecological risks of the formulations of seven neonicotinoid insecticides to the 7-spot ladybird, Coccinella septempunctata, so as to provide a reference for scientific use of neonicotinoid insecticides and protection of C. septempunctata.【Methods】The acute toxicity of the formulations of seven neonicotinoid insecticides, including 10% imidacloprid WP, 40% acetamiprid SP, 50% dinotefuran WP, 50% clothianidin WG, 40% imidaclothiz WG, 17% flupyradifurone SL and 25% thiamethoxam WG to the 2nd instar larvae of C. septempunctata was determined by using the method of residual film in glass tube, and the ecological risks of these insecticides were assessed. The solutions of the seven insecticides were prepared according to the maximum recommended field application rate, and sprayed on potted plants in the greenhouse to investigate the larval survival rate of C. septempunctata.【Results】The results of the indoor experiments showed that the acute toxicity of the seven neonicotinoid insecticides to the 2nd instar larvae of C. septempunctata was ranked in a descending order: 40% acetamiprid SP>40% imidaclothiz WG>10% imidacloprid WP>50% dinotefuran WP>50% clothianidin WG>25% thiamethoxam WG>17% flupyradifurone SL. The pot experiment in the greenhouse showed that the larval survival rates of C. septempunctata at 7 d after treatment with the seven insecticides at the maximum recommended field application rate were 10.00%-77.50%, and the highest larval survival rate of C. septempunctata was tested in the treatment with 25% thiamethoxam WG, while the lowest survival rate was observed in the treatment with 40% imidaclothiz WG. The results of ecological risk assessment showed that for a single application, the risk of 40% acetamiprid SP was unacceptable with the hazard quotient value in the farm (HQ_in) of more than 5, and those of the other pesticides were acceptable with the HQ_in values of less than 5. The hazard quotient values for crop or vegetable field outside the farm (HQ_{off crop or vegetable}) and for fruit tree garden outside the farm (HQ_{off fruit tree}) of these insecticides to C. septempunctata were less than 5, indicating that the risk is acceptable. After the second spray after 7 d, the risks of 40% acetamiprid SP and 50% dinotefuran WP were unacceptable with the HQ_in values of more than 5, and those of the other insecticides were acceptable with the HQ_invalues of less than 5. The HQ_{off crop or vegetable}and HQ_{off fruit tree}values of the other insecticides except 40% acetamiprid SP were less than 5, indicating that the risks of these insecticides are acceptable.【Conclusion】Acetamiprid and dinotefuran should not be used twice continuously and be used in rotation in order to avoid harm to C. septempunctata.

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Advances in research and application of sex pheromones of the tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae)

LIANG Yong-Xuan, WANG Qi-Jing, GUO Jian-Yang, WANG Yu-Sheng, ZHANG Yi-Bo, YANG Nian-Wan, ZHANG Gui-Fen, ZHOU Qiong, LIU Wan-Xue

Acta Entomologica Sinica 2023, 66 (6): 849-858. DOI: 10.16380/j.kcxb.2023.06.013

Abstract （427）

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The tomato leafminer, Tuta absoluta, is native to South America and a quarantine pest in the world nowadays, which can reduce the yield of the main host crop tomato by 80%-100% in severe cases. In over a decade, this insect pest has invaded and spread from its origin to almost the entire continent of Asia, Africa and Europe, becoming a major threat to the world tomato industry. T. absoluta was discovered in Ili, Xinjiang in 2017 and spread to Yunnan, Gansu and other regions in a short time, greatly threatening the healthy development of the tomato industry and other related agricultural industries in China. Internationally, sex pheromone-based monitoring, mass trapping and mating disruption control have become one of the important measures to control T. absoluta. In order to study the efficient and environmentally friendly population dynamics monitoring and control technology of T. absoluta, we summarized the research and application status of the sex pheromone in mornitoring, early warning and control of T. absoluta in this article. The females of T. absoluta release sex pheromones to attract males to mate mainly in the morning, and adult mating reaches the peak at 7:00 a.m. In 1995 and 1996, the major and minor components of the sex pheromone released from T. absoluta and their synthetic methods were reported successively. The major and minor components of this sex pheromone are (3E, 8Z, 11Z)-tetradecatrienyl acetate (TDTA) and (3E, 8Z)-tetradecadienyl acetate (TDDA), respectively, which constitute the sex pheromone in a ratio of about 90∶10. Bioassay results revealed that TDTA had a strong attraction to males, which could be further enhanced when its mixture with TDDA was used. In recent years, more efficient and convenient synthetic methods of sex pheromone components have been developed, providing good conditions for their large-scale production and application. At present, the sex pheromone of T. absoluta has been widely used in the control of this insect pest in the world, and good results have been achieved. Among the reported sex pheromone traps commonly used for monitoring and mass trapping this insect pest, the water basin trap and triangle trap are more effective. The common doses of sex pheromone contained in commercial lure core are 0.5, 0.8 and 3.0 mg. For field application, the corresponding trap type and sex pheromone dose should be selected according to the actual situation of habitat and growth stage of crops, damage degree, local natural conditions, etc. In addition, the mating disruption by using sex pheromone is also common in the control of T. absoluta, and its successful application requires a highly enclosed environment. Because sex pheromone has the advantages of high efficiency, safety and environmental protection in the monitoring and control of T. absoluta, its related research results can provide important reference for the sustainable control strategies and measures of this insect pest in China.

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Detection and recognition of grooming behaviors of Bactrocera dorsalis (Diptera: Trypetidae) based on YOLO V7 and TSM model

LIU Hu, ZHAN Wei, HE Zhang-Zhang, TANG Jian-Tao, JIANG Zhen-Yu, SUN Yong

Acta Entomologica Sinica 2023, 66 (6): 787-796. DOI: 10.16380/j.kcxb.2023.06.007

Abstract （394）

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【Aim】 Statistical analysis and study of insect grooming behaviors are important for pest control and human health. In view that the traditional method of manually recording grooming behaviors is time-consuming and error-prone, we proposed a computer vision and deep learning-based method for the detection and recognition of grooming behaviors of the Oriental fruit fly, Bactrocera dorsalis. 【Methods】 First, we processed the B. dorsalis video data to obtain frame images, and screened 3 000 images as the training dataset. We built the YOLO V7 target detection algorithm to detect B. dorsalis target in video data, and framed the target and cropped it by video processing algorithm. Finally, we migrated the pre-training weights to the training model by transfer learning method, and recognized seven grooming behaviors (foreleg grooming, head grooming, fore-midleg grooming, mid-hindleg grooming, hindleg grooming, wing grooming and stationary) of B. dorsalis using the temporal shift module (TSM) deep learning model based on non-local attention improvement. 【Results】 The accuracy and recall rate of the original video of the B. dorsalis dataset trained by YOLO V7 target detection algorithm were 99.2% and 99.1%, respectively. Applying this research algorithm to process the video dataset, and then recognizing and counting grooming behaviors through an improved TSM model based on the non-local attention module, we got the final average accuracy of over 97% with a standard deviation of less than 3%. Compared with the other four deep learning models (I3D, R2+1D, SlowFast and Timesformer), this research method had a ~9.76% improvement in accuracy, ensuring the accuracy of B. dorsalis grooming behavior detection and recognition. 【Conclusion】 The method proposed in this study greatly reduces the time of manual observation, and ensures the accuracy of grooming behavior recognition of B. dorsalis, providing new ideas and methods for researching insect behavior and contributing to the modern development of intelligent agriculture.

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Insect odorscape: From odor diffusion to pest control

JIAO Long, TAN Rong-Rong, CHEN Xun, WANG Hong-Juan, HUANG Dan-Juan, MAO Ying-Xin

Acta Entomologica Sinica 2023, 66 (7): 978-991. DOI: 10.16380/j.kcxb.2023.07.012

Abstract （383）

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The collective set of odors received by insects is called as insect odorscape. Insects rely on the reception and discrimination of the odorscape to complete life activities, such as the object localization, feeding, mating and oviposition. The behavior of insects can be manipulated by odorscape management for pest control strategy. In this article, we reviewed the research progress in the composition and diffusion of insect odorscape, influences of odorscape on insect behavior, factors affecting odorscape, odorscape reception and discrimination of insects, and the application of odorscape management in pest control. Finally, we analyzed and prospected the development direction and research focus of insect odorscape management in the future. For insects, the odor released by target is dispersed into plumes by air flow and mixed with the background odor carried in the air, which together form the odorscape. Insects search and locate the target along the target odor. The behavior of insects can be affected by the shape, composition and concentration of target odors. The background odor plays a complementary or warning role during the target localization of insects. Different background odors can synergize or interfere with the target localization of insects. The insect odorscape is mainly affected by the temperature, humidity, light, heavy metal elements and plant diseases and insect pests in the environment. Studies showed that the olfactory receptors of insects capture odorscape and transmit those odor signals to olfactory nerve centers such as antennal sensilla lobe along the olfactory nerves. Then, the odorscape is analyzed in the nerve centers by the mode of elemental processing or configural processing. The influences of background odor on insect target localization may be the results of the reciprocal addition, competitive binding or signal crosstalk of different odor molecules during the olfactory sensing and coding. At present, several kinds of green pest control technologies have been developed based on the odorscape management, such as insect behavior regulators, exogenous elicitors, breeding the crop varieties that can release resistant volatiles, “push-pull” technology and plant-mediated support system for natural enemies. In the future, it is necessary to further explore the behavioral, electrophysiological and neurological mechanisms of odorscape discrimination in insects, and optimize and integrate the green control technologies related to odorscape management, so as to build rational and efficient odorscape for insect pest control.

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Construction of exogenous DNA delivery system based on ovary-delivering peptide and Gal4-UAS binding property in Anopheles sinensis (Diptera: Culicidae)

YANG Xiao-Lin, LING Xia, SUN Quan, CHEN Jie, XIANG Kai, QIU Pin-Pin, HONG Jun-Feng, YAN Zhen-Tian, WANG Rong, CHEN Bin, QIAO Liang

Acta Entomologica Sinica 2023, 66 (6): 723-735. DOI: 10.16380/j.kcxb.2023.06.001

Abstract （375）

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【Aim】Based on the features that the P2C can be delivered into ovaries and the Gal4 protein can stably bind to the UAS sequence, to establish an efficient non-embryonic exogenous DNA delivery technical system in Anopheles sinensis.【Methods】The recombinant protein P2C-Gal4-DsRed was injected into the abdomen of female adults of A. sinensis at 20 h after sucking blood. The delivery efficiency of the recombinant protein P2C-Gal4-DsRed in the ovaries was analyzed by frozen section fluorescence observation and Western blot. The recombinant P2C-Gal4 DNA BINDING protein was prepared, transgenic plasmid and helper plasmid containing the 12×UAS repeat motif were constructed, and the in vitro binding between the recombinant protein P2C-Gal4 DNA BINDING and 12×UAS repeat motif was analyzed by electrophoretic mobility shift assay. The complexes P2C-Gal4 DNA BINDING recombinant protein+helper plasmid ITF36-12×UAS and P2C-Gal4 DNA BINDING recombinant protein+transgenic plasmid ITF2-12×UAS afm incubated in vitro were injected into the abdomen of female adults of A. sinensis at 20 h after sucking blood, and the DNA of their ovaries was extracted at 40 h after a blood meal. The delivery of exogenous DNA in vivo was analyzed by PCR amplification with specific primers and sequencing. 【Results】The ovaries of 100% female adults of A. sinensis injected with P2C-Gal4-DsRed showed obvious red fluorescence under the green filter, indicating that the P2C-Gal4-DsRed recombinant protein could be efficiently transferred into the ovaries of female adults of A. sinensis. The recombinant P2C-Gal4 DNA BINDING protein could stably bind to the 12×UAS repeat motif and the plasmid containing this repeat motif fragment. Exogenous DNA fragments were detected in the ovarian tissues of 91% and 93% of female adults of A. sinensis injected with P2C-Gal4 DNA BINDINGP2C-Gal4+ITF36-12×UAS and P2C-Gal4 DNA BINDING+ITF2-12×UAS afm, respectively. 【Conclusion】The exogenous DNA delivery technical system based on the P2C ovary-delivering peptide and the Gal4-12×UAS binding property was successfully established in A. sinensis. Through this technology platform, DNA molecules such as plasmids can be conveniently, rapidly and efficiently delivered into the ovaries of A. sinensis, laying a foundation for further simplifying genetic operations such as transgene, overexpression and gene knock-in.

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Research progress in insect gut microbes and the methods for studying their functions

MA Ling, CAO Jing-Yu, BAI Jian-Yang, XU Zhe, LI Lu, ZHANG Yue, MIN Meng-Ru

Acta Entomologica Sinica 2023, 66 (10): 1415-1424. DOI: 10.16380/j.kcxb.2023.10.014

Abstract （365）

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Insects are the most abundant and widespread group of animals in the world that harbor complex and diverse gut microbes. Different insects differ in gut structure, gut environment, edibility, age and external environment, and the composition and abundance of gut microbes also show difference. Insect gut microbes are mainly transferred vertically and horizontally between populations and individuals, and play a vital role in nutrient metabolism, physiological behaviour, defence, detoxification and many other functions in insect hosts. Insect gut microbes can be isolated from culture media by in vitro culture methods and rapidly identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and sequencing technologies such as 16S rRNA gene sequencing. The combination of metagenomics, proteomics, metabolomics and other omics technologies makes the identification and functional prediction of gut microbes more efficient. Microbial functions can be more accurately verified by in vitro experiments, microbial supplementation, microbiota transplantation and silencing of genes associated with microbial members. Sterile insects can be obtained by high temperature treatment, lysozyme treatment, sterile feeding and antibiotic treatment for functional verification experiments. However, the most widely used antibiotic method still has limitations in application. By exploiting the characteristics of gut microbes, genetic engineering of symbiotic bacteria can be used to control pests and insect-borne infectious diseases. At present, insect gut microbes play an important role in the fields of ecology, economy, energy and environmental protection. With the development and integration of new technologies, more insect-microbe interaction mechanisms will be revealed, and pest control methods through insect gut microbes will become more diverse, environmentally friendly and efficient.

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Structural characteristics and seasonal dynamics of ground-dwelling ant communities in three habitats in Lishui District, Nanjing, East China

GUO Zong-Lin, JIANG Fu-Guo, WANG Ya-Lu, CHEN Xiao-Yi, WANG Guo-Bing

Acta Entomologica Sinica 2023, 66 (6): 816-824. DOI: 10.16380/j.kcxb.2023.06.010

Abstract （351）

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【Aim】To investigate the diversity and seasonal dynamics of ground-dwelling ant communities in three habitats in Lishui District, Nanjing, East China.【Methods】A one-year seasonal sampling was conducted from August 2020 to July 2021 in three different sampling habitats (farmland, grassland and plantation forest) in Lishui District, Nanjing, and the individual density, species number, Simpson dominance index, Shannon-Wiener diversity index, Pielou’s evenness index and Jaccard similarity coefficient of grounddwelling ant communities, and the seasonal dynamics of each index in these three habitats were investigated.【Results】During August 2020 to July 2021, the dominant species of ground-dwelling ants in farmland in Lishui District, Nanjing were Tetramorium caespitum (490 individuals, 58.75%), Ochetellus glaber (116 individuals, 13.91%) and Formica japonica (98 individuals, 11.75%), those in grassland were T. caespitum (427 individuals, 58.17%) and Nylanderia bourbonica (110 individuals, 14.99%), and those in plantation forest were T. caespitum (240 individuals, 27.18%), F. japonica (121 individuals, 13.70%), N. sharpii (98 individuals, 11.10%) and Pristomyrmex punctatus (90 individuals, 10.19%). The numbers of species and individuals in ground-dwelling ant communities varied significantly between habitats, with the highest numbers of species and individuals (29 species, 883 individuals) collected from plantation forest and the lowest numbers of species and individuals (19 species, 734 individuals) collected from grassland. The analysis of variance showed that seasonal changes had a significant effect on the number of species and individual density of ground-dwelling ants in this region, while habitat changes had a significant effect on the number of species and no significant effect on the individual density, but there was no interactive effect of both seasonal and habitat changes on the number of species and individual density of ground-dwelling ants in this region. The analysis of community diversity showed that the seasonal trends in the Shannon-Wiener diversity index, Pielou’s evenness index and Simpson dominance index of the ground-dwelling ant communities in the three different habitats were basically the same, with an increasing trend followed by a decreasing trend, while the seasonal trends of the Simpson dominance index and Pielou’s evenness index were basically opposite. The Jaccard similarity coefficients of the ground-dwelling ant communities between farmland and grassland, farmland and plantation forest, and grassland and plantation forest were 0.73, 0.52 and 0.52, respectively, which were moderately similar to each other, while those of the grounddwelling ant communities between different months were low, and most of them were extremely dissimilar. 【Conclusion】The numbers of individuals and species in the ground-dwelling ant communities in Lishui District, Nanjing are relatively rich, and the structure of the ground-dwelling ant communities is significantly influenced by habitat type changes and seasonal changes, so attention should be paid to strengthen the protection of ant species resources in the region in different seasons.

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Research advances in the structure and function of insect fat bodies and their application in human disease models

MA Zhen-Gang, HE Yu-Bo, MA Qiang, WANG Jing-Lin, ZHOU Ze-Yang

Acta Entomologica Sinica 2023, 66 (9): 1246-1257. DOI: 10.16380/j.kcxb.2023.09.011

Abstract （350）

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Insect fat bodies are widely distributed in the body of insects, and they are a dynamically loose tissue that includes peripheral fat bodies and visceral fat bodies. The structure and function of insect fat bodies are closely related, and their structure changes with the changes of different life stages, and their functions also change. However, the most basic function of insect fat bodies is to act as the core tissue of insect life metabolism to synthesize and store substances. In addition, fat bodies, which are the target organs of various hormones, have many important functions and are related to the innate immunity, longevity, growth and development of insects. Therefore, the study on insect fat body is very important for the analysis of the important life phenomena of insects. In recent years, a large number of studies have taken insect fat bodies as research models for human diseases and drug development, and applied them in many fields such as human immunology, pathogenesis of human diseases, and new drug research and development. Here, in order to systematically deepen the understanding of the structure and function of insect fat bodies, the morphological structure, formation and metamorphosis, biological function, and their application and prospect in the study of human disease models were reviewed. Insect fat bodies would have great application potential in the construction of major human disease models and the exploration of disease pathogenesis.

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Nuclear receptor gene SfUSP regulates the molting development of the white-backed planthopper, Sogatella furcifera (Hemiptera: Delphacidae)

ZHOU Cao, GONG Ming-Fu, YANG Xi-Bin, YANG Hong, LONG Gui-Yun, JIA Ze-Yan, ZENG Qing-Hui, JIN Dao-Chao

Acta Entomologica Sinica 2023, 66 (5): 609-618. DOI: 10.16380/j.kcxb.2023.05.001

Abstract （328）

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【Aim】To explore the function of nuclear receptor ultraspiracle protein (USP) in the molting development of Sogatella furcifera nymph and its regulatory relationship with chitin synthesis and degradation. 【Methods】Based on the genome data of S. furcifera, the full-length cDNA sequence of SfUSP was amplified by RT-PCR. The expression levels of SfUSP in different developmental stages (1st-5th instar nymphs, 5th instar nymph prior to ecdysis, 5th instar nymph during ecdysis and female adult), tissues (head, integument, fat body, gut and leg) of the 5th instar nymph, female adult tissues (integument, wing, fat body, leg and ovary) and the day-1 5th instar nymph of S. furcifera after treatment with 100 ng/individual of 20E were detected by RT-qPCR. After the targeted silencing of SfUSP by microinjection of dsRNA into the day-1 5th instar nymph, the nymphal survival rate was calculated, the lethal phenotype of nymphs was observed and the expression levels of the key genes in chitin synthesis and degradation pathways were determined by RT-qPCR. 【Results】The full-length cDNA sequence of SfUSP (GenBank accession number: ON209396) of S. furcifera was obtained by cloning, with an open reading frame of 1 263 bp in length, encoding 420 amino acids. The predicted molecular weight of SfUSP is 47.27 kD with the theoretical isoelectric point of 7.18. Sequence analysis result showed that SfUSP contains five conserved domains of nuclear receptor family, and DNA-binding domain (DBD) and ligand-binding domain (LBD) are highly conserved. The developmental stage expression profiles showed that SfUSP was highly expressed in the 1st instar nymph, and the 5th instar nymphs prior to ecdysis and female adult. The tissue expression profiles showed that SfUSP was expressed highly in the head, integument, fat body and gut of the 5th instar nymphs, and in the wing, leg and integument of the female adult. In addition, at 12 h after microinjection of 20E (100 ng/individual), the expression level of SfUSP in the 5th instar nymph was significantly increased as compared with that in the control group. After targeted silencing of SfUSP expression, the nymphal survival rate of S. furcifera was significantly reduced compared with the control group (injected with dsGFP) and only 18.01% of that of the control group at 6 d after microinjection of dsRNA, with 51.46% individuals unable to molt successfully. In addition, after targeted silencing of SfUSP expression, the expression levels of the key genes SfCHS1, SfCHS1a, SfUAP and SfGFAT in chitin synthesis pathways and SfCht7, SfNAG1, SfNAG2, SfCDA1, SfCDA2 and SfCDA4 in chitin degradation pathways were significantly inhibited, but those of SfG6PI and SfCht10 were significantly increased as compared with those in the control group microinjected with dsGFP. 【Conclusion】SfUSP is a key gene in the growth and development of S. furcifera, which can affect the synthesis and degradation of chitin, and then regulates the ecdysis development of S. furcifera.

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Hybrid dysgenesis and P-element transposition in Drosophila

WANG Chun-Ming

Acta Entomologica Sinica 2023, 66 (7): 959-968. DOI: 10.16380/j.kcxb.2023.07.010

Abstract （327）

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Hybrid dysgenesis in Drosophila refers to the occurrence of some abnormal phenomena in the progeny when crossing certain strains of Drosophila, such as ovarian hypoplasia, abnormal segregation ratio, recombination in male meiosis, high mutation rate, high frequency of chromosomal aberrations, even leading to infertility of the progeny etc. Hybrid dysgenesis in Drosophila is caused by frequent transposition of the transposable element (TE), including P-element, I-element, hobo-element, Penelope-element, Paris-element， Helena-element etc. P-element is the first eukaryotic transposon to have its DNA sequence determined, and it is also one of the most well-studied animal transposons. Developed as a genetic engineering tool, P-element has played an important role in Drosophila transgenic research. Drosophila carrying Pelement in the genome is paternal strain (P strain), while that without Pelement is maternal strain (M strain). In a cross of M female×P male, the progeny shows hybrid dysgenesis, while the progeny of the mating combinations of P female×M male, M female×M male and P female×P male is normal. In the past 20 years, significant progress has been made in the research on the regulation mechanism of P-element. In addition to the original repressor mechanism, a piRNA ［P-element-induced wimpy testis (PIWI)-interacting RNA］ mechanism has been discovered. The repressor mechanism is based on the post-transcriptional splicing of three introns among four exons of P-element transposase. If all the three introns are spliced, the resulted mRNA contains four exons, which are translated into a 87 kD transposase, promoting P-element transposition. If only the first two introns are spliced, the resulted mRNA terminates translation prematurely at the stop codon contained in the 3rd intron segment, producing a 66 kD repressor that prevents P-element transposition. The piRNA mechanism discovered in recent years is a more common TE regulatory mechanism. The mechanism is similar to the CRISPR-derived RNA (crRNA) mechanism found in bacteria, and the genes encoding piRNA are also arranged in cluster, called piRNA cluster. The piRNA cluster transcribes a single-stranded RNA precursor molecule, splices to 23-32 nt piRNA, then binds to the PIWI protein to form a complex, and plays a role through two pathways: One is to degrade the target mRNA complementary to the piRNA sequence and play a post-transcriptional silencing effect; the other is to enter the nucleus, guide the epigenetic modification of the sequence of P-element or piRNA cluster, play a transcriptional inhibition of P-element, and play a transcriptional activation effect on piRNA cluster. It was found that both the repressor mechanism and the piRNA mechanism play a role in the regulation of P-element transposition. This review may help with the teaching and scientific research of the phenomenon of hybrid dysgenesis.

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Spatiotemporal expression of WntA during the embryonic development in Locusta migratoria manilensis (Orthoptera: Locustidae)

SONG Jia, MA Yu-Jie, PU Xue, JI Rong, KABAK Iliya, YUAN Liang

Acta Entomologica Sinica 2023, 66 (9): 1139-1149. DOI: 10.16380/j.kcxb.2023.09.001

Abstract （314）

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【Aim】 To explore the sequence characteristics of WntA-encoding protein in the Wnt gene family of Locusta migratoria manilensis and its spatiotemporal expression profile during the embryonic development, and lay a foundation for the further functional research of LmmWntA and mining other Wnt gene family members of L. migratoria manilensis. 【Methods】 The Wnt gene family gene LmmWntA of L. migratoria manilensis was cloned by PCR and identified by neighbor-joining (NJ) method. The amino acid sequence characteristics of LmmWntA were analyzed by homologous sequence multiple alignment. Whole-mount in situ hybridization was used to screen the transcriptional signals of LmmWntA in 17 consecutive embryonic developmental stages of L. migratoria manilensis after egg laying (AEL) to 12, 24, 35, 46, 56 and 65 h, and 3, 3.5, 4, 4.5, 5, 5.5, 6.5, 8, 8.5, 9.5 and 11 d. 【Results】 The full-length CDS of LmmWntA (GenBank accession number： MW052768) of L. migratoria manilensis was cloned and is 1 101 bp, encoding 336 amino acids. LmmWntA and WntA proteins of cephalochordates, insects, clawed animals and annelids were clustered into a monophyletic group of WntA subfamily. The middle region and C-terminus of LmmWntA maintain high homology with the WntA protein sequences of the corresponding species, except for the difference in the N-terminal signal peptide region, and LmmWntA was clustered with the AmWntA protein of Apis mellifera in Hymenoptera as a sister group with the amino acid sequence identity of 59.05%. LmmWntA was first expressed in the terminal growth region of the 35 h AEL and continued to be expressed in this region until the 4 d AEL, forming stripe expression in the abdomen of each segment of the neonatal segment, and continued to be expressed in the posterior half of the optic lobe, which develops into compound eyes in the future, from the 46 h AEL to the 8.5 d AEL of L. migratoria manilensis. LmmWntA was continuously expressed in the brain from the 56 h AEL to the 5.5 d AEL. At the 65 h AEL, the stripe-like expression signal of LmmWntA in each segment of the abdomen was gradually transferred to both sides of the midline of the abdomen, and there was a clear expression signal at the base of the antennae. At the 5.5 d AEL, the expression signal of LmmWntA was further transferred to the abdominal nerve. From the 3 d AEL, LmmWntA was expressed at the distal end of the ventral somite, and later transferred to the palate, foot joint and end. As the end of the 4.5 d AEL embryo began to invaginate to form proctodeum, LmmWntA was expressed in the ventral and anterior end of the invaginated proctodeum, and most of them invaginated to the 7th somite of the abdomen. At the 9.5 d AEL, LmmWntA was expressed at the wing germ disc. 【Conclusion】 LmmWntA was dynamically expressed during the embryonic development of L. migratoria manilensis, speculating that LmmWntA is involved in the development and formation of important tissues and organs such as the posterior segment growth of embryo, nervous system (brain and abdominal nerve), compound eye, antennae, posterior end of digestive system (proctodeum), jaw, chest appendages (leg and wing) of L. migratoria manilensis. The results of this study lay the foundation of developmental biology for further research on LmmWntA deficiency.

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Cloning and expression profiling of heat shock protein genes AcHsp83a and AcHsp83b from Arma chinensis (Hemiptera: Pentatomidae) and their response to high or low temperature and UV-B stresses

MENG Jian-Yu, JIN Xin, HE Long-Chun, ZHANG Xue-Xia, YANG Chang-Li, ZHANG Chang-Yu

Acta Entomologica Sinica 2023, 66 (11): 1425-1434. DOI: 10.16380/j.kcxb.2023.11.001

Abstract （303）

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【Aim】 To explore the molecular mechanism of the natural enemy insect Arma chinensis in response to high or low temperature and UV-B stresses.【Methods】 The heat shock protein genes AcHsp83a and AcHsp83b of A. chinensis were cloned by RT-PCR, and their sequence characteristics were analyzed by bioinformatics methods. RT-qPCR was used to detect the expression levels of AcHsp83a and AcHsp83b in different developmental stages (egg, 1st-5th instar nymphs, female adult and male adult), different adult tissues (head, thorax, abdomen, wing, antenna, fat body, leg, Malpighian tubules, mouthparts, midgut, ovary and testis), and female and male adults at 0 (CK), 6 and 24 h after exposure to high temperature of 38 ℃, and low temperature of 4 ℃, and at 0 (CK), 6 and 12 h after UV-B stress.【Results】 Two Hsp90 genes were cloned from A. chinensis, and namely AcHsp83a (GenBank accession no.: OP791883) and AcHsp83b (GenBank accession no.: OP791884). Their open reading frames (ORFs) were 2 172 and 2 163 bp in length, encoding 723 and 720 amino acids with the relative molecular weight of 83.12 and 82.90 kD and the isoelectric point (pI) of 4.94 and 4.97, respectively, and the C-terminal sequences both contain the conserved motif EEVD, showing that they belong to the cytoplasmic Hsps. AcHsp83a and AcHsp83b are highly conserved. The expression level of AcHsp83a was the highest in eggs, whereas that of AcHsp83b was the highest in adults. The expression level of AcHsp83a was the highest in the testis of male adults, whereas that of AcHsp83b was the highest in the midgut of female adults. When the female adults were exposed to 38 ℃, 4 ℃ or UV-B, the expression levels of AcHsp83a and AcHsp83b increased firstly and then decreased with treatment time, reaching the peak at 6 h. For the male adults, the expression level of AcHsp83a increased firstly and then decreased with treatment time, and reached the peak at 6 h after exposure to 38 ℃ or UV-B. The expression level of AcHsp83a in male adults decreased firstly and then increased with treatment time, and reached the peak at 24 h after exposure to 4 ℃. Compared with the control group, 38 ℃, 4 ℃ or UV-B exposure significantly decreased the expression levels of AcHsp83b in male adults. 【Conclusion】 The differential expression of AcHsp83a and AcHsp83b in A. chinensis suggests that the two genes play important roles in the growth and development of A. chinensis and contribute to its tolerance to extreme temperatures and UV-B stress.

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Analysis of the functional mechanism of ATP synthase subunit α in the metamorphosis of Helicoverpa armigera (Lepidoptera: Noctuidae) larvae

GENG Zi-Chen, CHANG Yan-Peng, ZHANG Bo, AN Shi-Heng, ZHAO Wen-Li

Acta Entomologica Sinica 2023, 66 (5): 619-627. DOI: 10.16380/j.kcxb.2023.05.002

Abstract （302）

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【Aim】This study aims to analyze the functional mechanism of ATP synthase subunit α in the metamorphosis and development of Helicoverpa armigera.【Methods】The open reading frame (ORF) of ATPS-α gene of H. armigera was amplified by PCR and analyzed by bioinformatics. qRT-PCR was employed to detect the expression levels of HaATPs-α in the cuticle, midgut and fat body of larva at the 5th instar molting stage and day-1-5 of the 6th instar, and the cuticle and fat body of the 6th instar larva after the induction of exogenous 20-hydroxyecdysone (20E)(0.1 mg/mL). The 6th instar larvae of H. armigera were injected with dsHaATPs-α, and the effects of knocking down the expression level of HaATPs-α by RNAi on the development and metamorphosis of larvae, and the ATP content, trehalose content, glucose content and trehalase activity in the larva were analyzed. 【Results】The ORF length of HaATPs-α of H. armigera is 1 677 bp. The amino acid sequence identity of ATPs-α in H. armigera, Spodoptera frugiperda, S. litura and Trichoplusia ni of Noctuidae of Lepidoptera was 96.56%, and their evolution relationship was close. The expression pattern analysis result showed that the expression levels of HaATPs-α in the cuticle and midgut of the day-3 6th instar larvae were the highest and also peaked in the fat body of the 5th instar larvae at the molting stage. Treatment with 20E(0.1 mg/mL) significantly upregulated the expression level of HaATPs-α in the 6th instar larvae compared with the control. Compared with the control group (injected with dsGFP), knocking down the expression level of HaATPs-α by RNAi delayed the larval development, significantly reduced larval weight, significantly increased larval mortality, significantly decreased pupation rate and adult emergence rate, significantly decreased ATP content and trehalase activity, significantly increased trehalose content, and significantly decreased glucose content. 【Conclusion】HaATPs-α not only controls ATP production, but also affects the contents of trehalose and glucose in H. armigera. Therefore, HaATPs-α plays an important role in larval metamorphosis. Furthermore, our results also provide experimental evidence and theoretical basis for using ATPs-α as a new target for pest control in the future.

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Resistance analysis of the antimicrobial peptide SAAP-148 against the pathogenic bacteria of bacterial intestinal disease in Bombyx mori

WANG Jue, SHEN Dong-Xu, PENG Yun-Wu, QIAN He-Ying, ZHAO Qiao-Ling, CHEN An-Li

Acta Entomologica Sinica 2023, 66 (6): 736-746. DOI: 10.16380/j.kcxb.2023.06.002

Abstract （301）

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【Aim】Bacterial intestinal disease is one of the main diseases of Bombyx mori. The purpose of this study is to explore the inhibitory effects of the broad-spectrum antimicrobial peptide SAAP-148 on the pathogenic bacteria of bacterial intestinal disease in B. mori, and to provide references for further use of antimicrobial peptides instead of antibiotics to prevent bacterial diseases in B. mori.【Methods】The expression levels of antimicrobial peptide genes in the midgut of healthy and bacterial intestinal disease-infected individuals of the day-4 5th instar larvae of B. mori were detected by qRT-PCR. The bacterial flora in the midgut of the day-4 5th instar larvae of B. mori infected with bacterial intestinal disease was isolated, and the phylogenetic tree was constructed by maximum likelihood method. The pathogenicity of the eight isolated bacteria and four common pathogenic bacteria of bacterial disease including Enterococcus faecalis, Bacillus bombyseptieus, B. thuringiensis and Serratia marcescens, to the healthy 5th instar larvae of B. mori was determined by feeding method (1×10¹⁰ and 1×10¹⁴ CFU/mL bacterial suspensions) and puncture inoculation method (2×10⁸ and 2×10⁹ CFU/mL bacterial suspensions). The inhibitory effects of the antimicrobial peptide SAAP-148 on the isolated pathogenic bacteria of intestinal disease and other common pathogenic bacteria of bacterial disease such as B. bombyseptieus were analyzed by agar plate diffusion method.【Results】The expression levels of the detected antibacterial peptide genes of B. mori in the midgut of the day-4 5th instar larvae of B. mori infected with bacterial intestinal disease were significantly up-regulated as compared with those of the healthy individuals, indicating that the antibacterial peptides in B. mori play a certain role in resisting bacterial intestinal disease. A total of eight pathogenic bacterial species (Mammaliicoccus sciuri, Aeromonas hydrophila, Enterobacter cancerogenus, E. bugandensis, E. hormaechei, Citrobacter freundii, Klebsiella pneumoniae and K. variicola) were isolated from the midgut of the day-4 5th instar larvae of B. mori infected with bacterial intestinal disease. The puncture results showed that the eight bacterial species were pathogenic. Among the eight bacterial species, M. sciuri, A. hydrophila, E. cancerogenus and E. bugandensis had strong pathogenicity, and E. hormaechei, C. freundii, K. pneumoniae and K. variicola were less pathogenic. The antibacterial peptide SAAP-148 had in vitro inhibitory effects on the eight isolated pathogenic bacteria and other four common pathogenic bacteria of B. mori bacterial disease, and the inhibitory effect increased with the increase of SAAP-148 concentration.【Conclusion】The antibacterial peptide SAAP-148 not only has obvious inhibitory effects on the pathogenic bacteria that may cause bacterial intestinal disease of B. mori, but also has inhibitory effects on the pathogenic bacteria that cause black chest sepsis, prodigiotic sepsis, bacterial poisoning of B. mori, and E. hormaechei which has produced resistance to ampicillin. SAAP-148 can be used as an ideal antibacterial agent to prevent the occurrence of bacterial disease of B. mori.

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Morphological characteristics and nesting behavior of Trypoxylon melanocorne (Hymenoptera: Sphecidae)

HU Jun-Jie, FANG Quan-Bo, WANG Xiang, SUN Kai-Li, LIU Xiao-Yu, HE Chun-Ling

Acta Entomologica Sinica 2023, 66 (6): 805-815. DOI: 10.16380/j.kcxb.2023.06.009

Abstract （300）

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【Aim】 As carnivorous insects preying on spiders, different species of Trypoxylon possess obviously different nesting strategies. This study aims to clarify the morphological characteristics and nesting behavior of T. melanocorne, so as to reveal the nesting and survival strategies of Trypoxylon. 【Methods】Man-made nest-trap boxes were set up by choosing different habitats in the Yugong Forest Farm and Nanshan Forest Farm in Jiyuan City, Henan Province, Central China from 2019 to 2020, and then the trap-nests that were nested by T. melanocorne adults were regularly collected. The internal structure data of the trap-nests were measured by dissecting trap-nests, and the development of offspring was observed and the parasitic enemies were collected in the laboratory. 【Results】 A total of 111 trap-nests nested by T. melanocorne adults were collected in the Yugong Forest Farm and Nanshan Forest Farm in Jiyuan City, Henan Province during 2019-2020, and 511 brood cells were dissected. The average number of eggs laid by females in a single trap-nest was 4.60±2.39 grains, and the majority of offspring was female (female to male ratio=2∶1). The average length of nests and length of brood cells were (123.38±46.45) and (16.01±5.57) mm, respectively. The numbers of intercalary cells and nests with vestibular cells accounted for 5.04% and 6.09%, respectively, of the total number of cells. The number of brood cells was significantly affected by the length of nests, and the length of cells of females was significantly longer than that of males. Two parasitic enemies of T. melanocorne, Trichrysis pellucida (Chrysidoidae) and Amobia quatei (Sarcophagidae) were found, with the parasitism rates of 196% and 1.57%, respectively. 【Conclusion】 The results of this study suggest that the population size of T. melanocorne distributed in the two forest farms in the southern Taihang Mountains, Henan Province is small, female progeny are more numerous than males, and one of the reasons for the small population size probably is low adult eclosion rate and sex ratio imbalance.

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Age-stage, two-sex life table of Tuta absoluta (Lepidoptera: Gelechiidae) at different humidities

ZHANG Bo-Chen, XU Shuang-Ye, WU Zi-Qing, ZHANG Rui, ZHENG Wei-Feng, LI Ya, HAO Chi, YU Qin

Acta Entomologica Sinica 2024, 67 (1): 78-89. DOI: 10.16380/j.kcxb.2024.01.009

Abstract （297）

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【Aim】To clarify the impact of humidity change on the growth, development and fecundity of Tuta absoluta.【Methods】At the relative humidities of 15%, 35%, 55%, 75% and 95% indoor, the developmental parameters including developmental duration, pre-oviposition period, generation time, larval survival rate, adult survival rate, and number of eggs laid per female of T. absoluta were measured. The age-stage, two-sex life table s of T. absoluta were constructed, and population parameters including survival rate, fecundity, life expectancy, and reproduction value were calculated using the age-stage, two-sex life table.【Results】At the relative humidities of 15%－95%, the egg duration at the relative humidity of 15% and 95% were significantly longer than those at the relative humidities of 35%, 55%, and 75%. The 4th instar larval duration first shortened and then lengthened with the relative humidity increased. The male adult longevity increased with the rising relative humidity, reaching the maximum at the relative humidity of 95%. The female adult longevity was the longest at the relative humidity of 75%. The generation time was significantly longer at relative humidity of 95% than those at other relative humidities. The number of eggs laid per female increased with the increasing relative humidity. The initial oviposition time of female adults was affected by the relative humidity, the initial oviposition time were 31, 27, 27, 27 and 31 d at the relative humidities of 15%, 35%, 55%, 75% and 95%, respectively. The population age specific net maternity and age-stage-specific reproductive value increased with the rising relative humidity, reaching the maximum at the relative humidity of 95%. The intrinsic rate of increase and finite rate of increase initially increased and then decreased with the rising relative humidity, the net reproductive rate increased with the rising relative humidity. The mean generation time initially decreased and then increased with the rising relative humidity. According to the parameters of the population life table, the prediction of population dynamics within next 60 d indicated that the relative humidity of 95% was conducive to the increase of population size, relative humidities of 15% and 95% were unfavorable to the increase of the population generation number. The impacts of different relative humidities on the survival rates of eggs and larvae were significant through linear regression fitting. 【Conclusion】Within the test setting relative humidity range, the optimal relative humidities for the growth and development of T. absoluta are 55% and 75%, and the optimum relative humidity for reproduction are 95%.

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Molecular characteristics and functional study of heat shock protein gene SmHsp60 in Sitodiplosis mosellana (Diptera: Cecidomyidae)

MA Qian, DONG Jin-Hui, LI Fang-Xiang, ZHU Ke-Yan, CHENG Wei-Ning

Acta Entomologica Sinica 2023, 66 (7): 859-869. DOI: 10.16380/j.kcxb.2023.07.001

Abstract （295）

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【Aim】The wheat blossom midge, Sitodiplosis mosellana, an important agricultural pest, survives under temperature extremes during summer and winter by diapause. This study aims to explore the relationship between heat shock protein 60 (Hsp60) gene expression and diapause development and temperature tolerance in the diapause process of S. mosellana.【Methods】 The full-length cDNA sequence of Hsp60 of S. mosellana (SmHsp60) was amplified via RACE and RT-PCR technologies, and analyzed via bioinformatics. qPCR was used to detect the expression levels of SmHsp60 in the S. mosellana larvae at different stages from pre-diapause to post-diapause development including pre-diapause, diapause, post-diapause quiescence and post-diapause development, as well as oversummering larvae under extremely high temperature stress ［exposed to water bathes at 34, 40, 45 and 50 ℃ for 1 h, and 35 ℃ for 0 (control), 15, 30, 60 and 120 min］ and overwintering larvae under extremely low temperature stress ［exposed to 0, -5, -10 and -15 ℃ for 1 h, and -5 ℃ for 0 (control), 15, 30, 60 and 120 min］. The recombinant SmHsp60 protein was obtained by prokaryotic expression and affinity column chromatography, and its ability to suppress the thermal aggregation of mitochondrial malate dehydrogenase (MDH) at 43 ℃ was examined by colorimetry and SDS-PAGE.【Results】 The full-length cDNA sequence of SmHsp60 (GenBank accession no: KR733065) of S. mosellana obtained is 2 270 bp in length, which contains an open reading frame (ORF) of 1 722 bp in length encoding a protein of 573 amino acids with the relative molecular weight of 60.7 kD. Amino acid sequence analysis indicated that SmHsp60 contains the classical signature sequences of mitochondrial Hsp60, and displayed the highest amino acid identity and the closest relationship to Hsp60 from Contarinia nasturtii of Cecidomyiidae. qPCR detection result showed that the expression level of SmHsp60 did not change significantly in the diapause stage, but began to increase gradually in the post-diapause quiescence stage with a peak in early-to-mid phase of post-diapause quiescence (i.e. December and next January) and was significantly higher than those in the other developmental stages. Compared to the untreated control, the expression of SmHsp60 in the oversummering larvae under 35 and 40 ℃for 1 h and 35 ℃ for 30-60 min and that in the overwintering larvae under -5 ℃ for 1 h was significantly induced, while the expression level of SmHsp60 did not change significantly above 45 ℃ or below -10 ℃. The highly purified recombinant SmHsp60 was able to effectively suppress the thermal aggregation of MDH, indicating its significant molecular chaperone function.【Conclusion】 SmHsp60 is involved in diapause regulation of S. mosellana and might play a role in diapause termination, as well as heat tolerance and cold tolerance during diapause.

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Effects of the gustatory receptor gene EscrGR8 on the fecundity of female adults of Eucryptorrhynchus scrobiculatus (Coleptera：Curculioniclae)

GUO Xiao-Li, WEN Chao, WEN Jun-Bao, WEN Xiao-Jian

Acta Entomologica Sinica 2024, 67 (3): 307-317. DOI: 10.16380/j.kcxb.2024.03.001

Abstract （294）

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【Aim】 To analyze and elucidate the molecular characteristics and function of the gustatory receptor gene EscrGR8 in Eucryptorrhynchus scrobiculatus, and to reveal its role in the regulation of the fecundity of female adult. 【Methods】 Based on the antennal transcriptome database of E. scrobiculatus, the cDNA full-length sequence of EscrGR8 was cloned using RACE. The expression levels of EscrGR8 in different developmental stages (egg, 1st－6th instar larvae, pupa, female adult, and male adult), and female and male adult tissues (head without antennae and proboscis, antennae, mouthparts, midgut, forefoot, testicles, ovaries, male copulatory organ and female ovipositor) of E. scrobiculatus were detected by qRT-PCR. The expression levels of EscrGR8 at 0, 6, 12, 24, 36, 48 and 72 h after RNAi through microinjection of dsRNA into female adults were detected by qRT-PCR. The oviposition selection rates, total numbers of eggs laid and hatching rates of eggs laid by female adults under different soil moisture conditions (0-10%, 11%-20%, 21%-40%, 41%-60%, 61%-80%, and 81%-100%) at 1-5 d and 6-11 d after dsEscrGR8 microinjection were determined, and the effects of inhibition of the EscrGR8 expression on the oviposition preference and fecundity of female adults were studied. 【Results】 The full-length cDNA sequence of EscrGR8 (GenBank accession no.: OR836580) of E. scrobiculatus was successfully cloned with the open reading frame (ORF) of 1 251 bp in length, encoding 416 amino acids. EscrGR8 has six transmembrane domains. Multiple sequence alignment and phylogenetic analysis results showed that EscrGR8 has a low homology to the GRs of other insects, and the amino acid sequence identity with AgraGR64f of Anthonomus grandis is 30.96%. qRT-PCR result showed that there were significant differences in the expression levels of EscrGR8 in different developmental stages and adult tissues of E. scrobiculatus. EscrGR8 had the highest expression level in female adults, and the lowest expression level in eggs. EscrGR8 was highly expressed specifically in the female ovaries. Microinjection of dsEscrGR8 not only significantly reduced the expression level of EscrGR8 within a certain period of time, but also had a significant impact on the oviposition preference of female adults. At 1-5 d after microinjection of dsEscrGR8, the oviposition selection rate and hatching rate of eggs laid by female adults under soil condition with the moisture content of 21%-40% were significantly reduced by 2466% and 1583%, respectively, compared with those of the dsGFP-microinjected control group. The oviposition selection rate increased significantly by 28.39% under soil condition with the moisture content of 81%-100%, and almost all of the eggs laid by female adults failed to hatch. 【Conclusion】 This study has confirmed the effect of gustatory receptor gene EscrGR8 on the oviposition preference and fecundity of female adults of E. scrobiculatus, which is helpful for understanding the diversity and functional specificity of gustatory receptor genes in insects.

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Research progress of behavioral manipulation techniques of Tuta absoluta (Lepidoptera: Gelechiidae)

LI Xiao-Wei, YI Song-Wang, CHEN Li-Min, CHENG Jiang-Hui, ZHOU Shu-Xing, LV Yao-Bin

Acta Entomologica Sinica 2023, 66 (6): 835-848. DOI: 10.16380/j.kcxb.2023.06.012

Abstract （288）

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The South American tomato pinworm, Tuta absoluta, is a worldwide devastating pest on tomatoes. This insect pest invaded China in 2017 and showed a trend of spread, posing a serious threat to tomato production in China. Unreasonable use of insecticides for control of this insect pest has led to the increasing level of resistance and the decrease of control efficacy. Consequently, there is an urgent need to develop novel green control technologies. Physical control trapping technique and olfactory behavior manipulation technique are important components of the integrated pest management program. In this article, the research progress of physical control trapping (light traps and color traps) and olfactory behavior manipulation (sex pheromone and plant volatiles) in T. absoluta were summarized. Color significantly affects the trapping efficiency of pheromone traps and sticky color traps. White, black and blue traps attract more T. absoluta adults in the field. The black light traps and LED traps with the wavelength of 470 nm have the best trapping efficiency on T. absoluta, and also have synergistic effects on sex pheromone. The sex pheromone of T. absoluta includes the major component (3E, 8Z, 11Z)-tetradecatrienyl acetate and the minor component (3E, 8Z)-tetradecadienyl acetate, in a ratio of ~9∶1. The optimal trapping blend for mass trapping is (3E, 8Z, 11Z)-tetradecatrienyl acetate and (3E, 8Z)-tetradecadienyl acetate in a ratio of 95∶5, and delta traps with sex pheromone lure show the highest trapping efficiency in comparison with other trap types. The sex pheromone of T. absoluta has been widely used for monitoring, mass trapping and mating disruption. Plant volatiles and traditional food attractant volatiles affect the host selection and oviposition of T. absoluta. Octyl acetate, phenylacetaldehyde+acetic acid blend, acetic acid+3-methyl-1-butanol blend, and a blend consisting of limonene, β-ocimene, α-terpinene, δ-elemene and (E)-β-caryophyllene show attractive activities to T. absoluta. p-Quinone, 2-carene, d-curcumene and 1,2-diethylbenzene in tomato can serve as oviposition stimulants to T. absoluta. By contrast, 1-fluorododecane, caryophyllene, curcumene, elemene, humulene, zingiberene, tridecan-2-one, undecan-2-one, (Z)-3-hexenyl propanoate and methyl salicylate have adverse effects on host selection, oviposition or growth and development of T. absoluta. Finally, current problems of behavioral manipulation techniques of T. absoluta, such as unclear mechanisms, unstable effects, and lack of combined application technology with other green control strategies, were discussed, and potential research directions were prospected, which will provide a reference for the development of green control technologies based on insect behavioral manipulation in this pest.

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Morphology and development of the internal reproductive system of Monochamus alternatus (Coleoptera: Cerambycidae) adults

CHEN Jin, LI Hui, HU Tian-Yi, YANG Hua-Lei, WEI Jia-Hang, JIN Lin, HAO De-Jun

Acta Entomologica Sinica 2023, 66 (9): 1210-1220. DOI: 10.16380/j.kcxb.2023.09.008

Abstract （284）

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【Aim】To clarify the structure and developmental process of the internal reproductive system of Monochamus alternatus adults and provide a theoretical basis for its reproductive mechanism research and population dynamics monitoring.【Methods】The internal reproductive system of M. alternatus adults at different ages (day-old) was anatomically observed under optical microscope to clarify its structural characteristics and developmental classification criteria, and the developmental process of the internal reproductive system of female and male adults was determined by divison of developmental levels. 【Results】The female internal reproductive system of M. alternatus adults is composed of one pair of ovaries, one pair of lateral oviducts, common oviduct, copulatory pouch, spermathecal duct, spermatheca, spermathecal gland , ovipositor and genital cavity. According to the morphology and color of ovarioles and spermathecal glands, the sexual maturation process of female adults can be divided into the following stages: Transparent stage (stage Ⅰ), primary vitellogenesis stage (stage Ⅱ), secondary vitellogenesis stage (stage Ⅲ) and egg maturation stage (stage Ⅳ). Ovarioles grow continuously during the ovarian development, and the color changes from transparent milky white to yellow. The morphology and color of the spermathecal gland changes from flat and translucent to full and yellow. The male internal reproductive system of M. alternatus adults is composed of one pair of testes, two pairs of accessory glands, one pair of vas deferens, one pair of vesicula seminalis, one pair of ejaculatory ducts, circulator and aedeagus. According to the morphology and color of the testes, vesicula seminalis and accessory glands, the sexual maturation process of male adults can be divided into four stages including transparent stage (stage Ⅰ), initial stage of spermiogenesis (stage Ⅱ), peak period of spermiogenesis (stage Ⅲ) and maturing stage (stage Ⅳ). The testicular long diameter changes little. The color of the testis, vesicula seminalis and circulator changes from milky white and translucent to white. The morphology and color of the accessory gland changes from small and translucent to swollen and transparent. The development of the internal reproductive system of both female and male adults is mainly concentrated at the stages Ⅱ-Ⅲ. In terms of the developmental process of the internal reproductive system, male adults develop more rapidly and their internal reproductive system is already mature at the 12-day-old, while the internal reproductive system of female adults is mature at the 15-day-old. 【Conclusion】 This study has clarified the basic structure and developmental processes of the internal reproductive system of female and male adults of M. alternatus, not only providing a theoretical basis for further research on the reproductive mechanism of M. alternatus, but also providing a reference for predicting the peak ovioposition period of M. alternatus in production practice.

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Research progress of the population genetic differentiation and environmental adaptation mechanisms in Apis cerana cerana (Hymenoptera: Apidae)

CHEN Bing, LUO Jia-Yu

Acta Entomologica Sinica 2023, 66 (9): 1258-1270. DOI: 10.16380/j.kcxb.2023.09.012

Abstract （282）

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Apis cerana cerana is a critical and important pollinator in China. This bee species has a wide distribution in various habitats, and exhibits several advantages as pollinator, e.g., agility in flight, long nectar gathering period and strong adaptability. However, in recent years, A. c. cerana has been facing an unprecedented decline in population diversity. In order to protect the genetic resources of these specific populations, researchers studied the physiology and mechanism of genetic differentiation and environmental adaptation in A. c. cerana based on geometric morphology, molecular biology and genomics technologies. Meanwhile, the diverse populations of A. c. cerana in China provided rich materials for analyzing their adaptive evolution. In this article, we summarized the research progress from the four aspects: The correlation between population genetic differentiation and environmental changes, the morphological variation and environmental adaptation, the enviroment-adaptive physiological and behavioral changes, and the genetic mechanisms behind these phenotypic changes of A. c. cerana populations. Previous studies showed that changes in physical barriers and ecological environment, especially those related to altitude and latitude, were the main reasons for the differentiation of A. c. cerana populations. Among the climatic factors, temperature, oxygen, radiation and humidity had important effects on the morphological development and eco-physiological traits of A. c. cerana. The morphological changes were mainly explained by variation in body size and color. Changes in metabolic physiology and behaviors have been evolved as a crucial adaption strategy. Population genetics and genomics based on modern genomics and molecular biology techniques showed that genes and pathways related to social division of labor, learning and perceiving behavior, information perception, growth and development, thermal adaptation and metabolism are subject to natural selection. These findings provide molecular evidence for the ability of A. c. cerana to adapt to different habitats and the evolution of bee species. However, the specific molecular evolution mechanisms for the environmental adaption of bees await further investigation. Our review on the mechanisms of genetic differentiation and environmental adaption of A. c. cerana will deepen our understanding of the evolutionary history and genetic diversity of ancient bee species, and lay a foundation for further studies on the adaptive mechanisms of social insects to different environments and the development of effective conservation strategies.

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Effects of carrying Bursaphelenchus xylophilus on the bacteria in the gut and trachea of adult Monochamus alternatus (Coleoptera: Cerambycidae)

GU Yu-Tong, ZHU Hao-Cheng, CHANG Yue, ZHOU Jiao, FAN Jian-Ting, ZHAO Li-Lin

Acta Entomologica Sinica 2023, 66 (10): 1319-1328. DOI: 10.16380/j.kcxb.2023.10.006

Abstract （282）

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【Aim】 To investigate the effects of Bursaphelenchus xylophilus in Monochamus alternatus on the bacteria in the gut and trachea of M. alternatus.【Methods】The whole gut and trachea were isolated from the collected M. alternatus adults carrying B. xylophilus in the field to extract DNA for sequencing and splicing of the 16S rDNA gene. The composition, structure, abundance and diversity of bacteria in the gut and trachea of M. alternatus adults carrying B. xylophilus were analyzed by bioinformatics methods. 【Results】A total of 15 phyla, 26 classes, 66 orders, 110 families, 201 genera, 296 species and 444 operational taxonomic units (OTUs) of bacterial flora in the gut and trachea of M. alternatus adults carrying B. xylophilus were detected. There was no significant change in the dominant bacterial flora in the gut between M. alternatus adults carrying B. xylophilus and M. alternatus adults without carrying B. xylophilus, and their dominant bacterial flora were Proteobacteria and Enterobacterales. Proteobacteria and Enterobacterales were the dominant bacterial flora in the trachea of M. alternatus adults carrying B. xylophilus, while Firmicutes and Lactobacillales were the dominant bacterial flora in the trachea of M. alternatus adults without carrying B. xylophilus. The diversity and abundance of bacteria in the trachea of M. alternatus adults carrying B. xylophilus were higher than those of M. alternatus adults without carrying B. xylophilus, and the bacterial community structure in the trachea of M. alternatus adults carrying B. xylophilus was significantly different from that of M. alternatus adults without carrying B. xylophilus. Serratia and Enterobacter were enriched in the gut and trachea of M. alternatus adults carrying B. xylophilus. 【Conclusion】The introduction of B. xylophilus has significant effects on the composition, structure, abundance and diversity of bacterial flora in the trachea of M. alternatus adults. Serratia and Enterobacter in the trachea of M. alternatus adults may be closely related to the B. xylophilus- M. alternatus complex. The increase of Serratia in the trachea of M. alternatus adults carrying B. xylophilus may be associated with the suppressed tracheal immunity of M. alternatus. This study provides a theoretical basis for the study of bacterial diversity in the gut and trachea of M. alternatus, and a new direction for the prevention and control of B. xylophilus.

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Cloning of Cu/Zn-SODl, Cu/Zn-SOD2 and Fe/Mn-SOD in Liposce1is bostrychophilα (Psocoptera: Liposce1ididae) and their responseto high and1ow temperature stresses

WANG Xiao, XU De-Jun, ZHU Bin-Jian, XU Jun-Ting, AO Guo-Hong, ZHANG Chang-Yu, HAN Kai-Yu

Acta Entomologica Sinica 2024, 67 (1): 1-8. DOI: 10.16380/j.kcxb.2024.01.001

Abstract （279）

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【Aim】 To reveal the role of the superoxide dismutase genes in Liposcelis bostrychophila in response to high and low temperature stresses. 【Methods】The cDNAs of three superoxide dismutase genes Cu/Zn-SOD1, Cu/Zn-SOD2 and Fe/Mn-SOD of L. bostrychophila were cloned by RT-PCR, and their sequence characteristics were analyzed by bioinformatics methods. RT-qPCR was used to detect the relative expression levels of Cu/Zn-SOD1, Cu/Zn-SOD2 and Fe/Mn-SOD in adults at 0, 1 and 2 h under high temperature (42 ℃) and low temperature (4 ℃) stresses. 【Results】 LbCu/Zn-SOD1, LbCu/Zn-SOD2 and LbFe/Mn-SOD (GenBank accession numbers are OQ938782, OQ938783 and OQ938784, respectively) of L. bostrychophila were cloned, with the open reading frames (ORFs) of 465, 630 and 636 bp in length, encoding 154, 209 and 211 amino acids with the relative molecular weights of 15.85, 22.33 and 23.72 kD, and the isoelectric points of 6.17, 7.68 and 6.79, respectively. LbCu/Zn-SOD1 and LbCu/Zn-SOD2 had one and two Cu/Zn superoxide dismutase signatures, respectively. LbFe/Mn-SOD had one Fe/Mn superoxide dismutase signature. The results of phylogenetic analysis showed that Cu/Zn-SOD1, Cu/Zn-SOD2 and Fe/Mn-SOD were highly conserved in insects. The expression of LbCu/Zn-SOD1, LbCu/Zn-SOD2 and LbFe/Mn-SOD in adults of L. bostrychophila was induced by high temperature42 ℃ stress, and the expression levels of LbCu/Zn-SOD1 and LbCu/Zn-SOD2 inadults of L. bostrychophila were significantly higher than that of the control at 1 and 2 h. The expression level of LbFe/Mn-SOD in adults of L. bostrychophila was significantly lower than that of the control at 1 h and significantly higher than that of the control at 2 h under42 ℃stress. There was no significant difference in the expression levels of LbCu/Zn-SOD1 and LbCu/Zn-SOD2 inadults of L. bostrychophila at 1 h, while that of LbFe/Mn-SOD decreased significantly at 1 h and those of LbCu/Zn-SOD1, LbCu/Zn-SOD2 and LbFe/Mn-SOD increased significantly at 2 h under 4 ℃stress as compared with that of the control. 【Conclusion】 The superoxide dismutase genes LbCu/Zn-SOD1, LbCu/Zn-SOD2 and LbFe/Mn-SOD are involved in the tolerance of L. bostrychophila to extreme temperature stress.

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Gene cloning, expression profiling and ligand binding characteristics of GmolNPC2 from Grapholita molesta (Lepidoptera: Tortricidae)

LI Chun-Qin, ZHANG Yu-Xi, XU Shi-Cai, LI Bo-Liao, CHEN Xiu-Lin, LUO Kun, LI Guang-Wei

Acta Entomologica Sinica 2023, 66 (7): 870-884. DOI: 10.16380/j.kcxb.2023.07.002

Abstract （277）

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【Aim】The purpose of this study is to provide a theoretical reference for the further study on the function of the Niemann-Pick type C2 protein (NPC2) of Grapholita molesta GmolNPC2 in olfactory sensing.【Methods】Based on the antennal transcriptome data of G. molesta, the full-length cDNA sequence of GmolNPC2 was amplified by RT-PCR, and the phylogenetic analysis and 3D structure model prediction of GmoNPC2 were performed. The relative expression levels of GmolNPC2 in different developmental stages (egg, 1st-5th instar larvae, pupa, and female and male adults) and different tissues (antenna, head without antenna, thorax, abdomen, leg, and wing) of the 3-day-old male and female adults were detected by RT-qPCR. The inhibitory constant (K_i) values of the recombinant GmolNPC2 to 44 odorant ligands including six sex pheromones and 38 host plant volatile compounds were determined by fluorescence competitive binding assays to analyze the binding ability of GmolNPC2 to odorant ligands. By using molecular docking simulations, the binding energy of GmolNPC2 with different odorant ligands was calculated and the key amino acid residues of protein-ligand interactions were predicted.【Results】The full-length cDNA sequence of GmolNPC2 (GenBank accession no.: OQ054801) of G. molesta was obtained and the open reading frame (ORF) is 438 bp in length, encoding 145 amino acids. Multiple sequence alignment showed that GmolNPC2 has the typical structural characteristics of NPC2 of insects. Phylogenetic analysis showed that the reported NPC2s of lepidopteran insects were clustered into two branches, and the GmolNPC2 sequence was highly identic to the NPC2 sequences of Leguminivora glycinivorella, Pectinophora gossypiella, and Manduca sexta, which were clustered into one branch. RT-qPCR detection result showed that the expression levels of GmolNPC2 in the male adult and egg were significantly higher than those in other developmental stages. The expression level of GmolNPC2 was the highest in the wing of the 3-day-old male and female adults followed by that in the antenna, and the lowest in the thorax, abdomen, and leg. The binding spectrum of the recombinant GmolNPC2 was narrow with only 17 out of 44 tested odorant ligands, among which, the recombinant GmolNPC2 exhibited strong binding abilities to (Z)-8-dodecenyl acetate, benzyl alcohol, and cis-3-hexenyl acetate, with the K_i values of (4.117±0.046), (4.845±0.079) and (3.979±0.167) μmol/L, respectively. The molecular docking simulation result showed that the binding energy between GmolNPC2 and each odorant ligand was different, which was consistent with the results of the above fluorescence binding assays. Hydrophobic amino acid residues and hydrogen bonds play an important role in GmolNPC2 binding with different odorant ligands.【Conclusion】 GmolNPC2 has the conserved structure of the insect NPC2 family and is highly expressed in the egg and adult, and the wing and antenna of adult, speculating that GmolNPC2 participates in different physiological processes in G. molesta. The recombinant GmolNPC2 selectively binds sex pheromones and host plant volatile compounds, indicating the involvement of GmolNPC2 in the detection and transportation of volatile semiochemicals.

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Functional analysis of the G-protein β-subunit gene in the brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae)

XU Hang-Peng, REN Peng-Peng, ZHANG Chuan-Xi, LU Jia-Bao

Acta Entomologica Sinica 2024, 67 (4): 456-467. DOI: 10.16380/j.kcxb.2024.04.002

Abstract （273）

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【Aim】This study aims to identify the G-protein β-subunit gene (NlGβ) in the brown planthopper, Nilaparvata lugens, and analyze its function, so as to supply a potential novel target gene for RNAi-based control of N. lugens. 【Methods】The coding sequence (CDS) of NlGβ of N. lugens was cloned and verified using PCR, and subjected to bioinformatics analysis. The spatiotemporal expression patterns of NlGβ were analyzed based on its transcriptome expression profiles in different developmental stages (egg, 1st-5th instar nymphs, and female and male adults) and adult tissues (head, leg, gut, cuticle, fat body, female reproductive system, and male reproductive system) of N. lugens. Microinjection of dsRNA against NlGβ was performed on the 2nd and 5th instar nymphs to silence NlGβ. Individual and female reproductive system phenotypes were observed, and the survival rate, number of eggs laid per female, and egg hatching rate were counted. Additionally, transmission electron microscopy was employed to observe the lateral oviduct intumescent region. 【Results】 The CDS of NlGβ (GenBank accession no.: XP_022200908.1) of N. lugens was 948 bp in length. The NlGβ protein comprised seven WD40 domains and four WD_REPEATS_1 motifs, indicating its conservation. Apart from the homologous proteins found in orthopteran insects, homologous NlGβs from other insect orders clustered well within the same evolutionary branch. The expression level of NlGβ exhibited periodic change during the 1st-3rd instar nymphal stages, and those in the 5th instar female nymphs and female adults were higher than those in the 5th instar male nymphs and male adults. NlGβ was expressed in various tissues of adults, with the highest expression level in the fat body, and the expression level of NlGβ in female reproductive system was higher than that in male reproductive system. Silencing NlGβ in the 2nd instar nymphs resulted in molting difficulty, leading to a significant decrease in the survival rate compared to the dsGFP control group. Silencing NlGβ in the 5th instar nymphs resulted in abnormal abdominal swelling in adult females, malformed ovarian development, a significant decrease in the number of eggs laid per female compared to the dsGFP control group, failure of egg hatching, an increase in secretion within the lateral oviduct intumescent region, and degradation of epithelial cells. 【Conclusion】 NlGβ is closely associated with the growth and development of N. lugens and the reproduction of its female individuals.

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Regulation of adipokinetic hormone on the growth and development of the Bactrocera dorsalis (Diptera: Tephritidae) larva

HOU Qiu-Li, ZHANG Han-Qiao, JIANG Hong-Bo, WANG Jin-Jun

Acta Entomologica Sinica 2023, 66 (5): 628-635. DOI: 10.16380/j.kcxb.2023.05.003

Abstract （272）

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【Aim】Adipokinetic hormone (AKH), a type of neuropeptide, plays central roles in regulating development and behavioral events in diverse insects. Investigating the functions of AKH on the growth and development of Bactrocera dorsalis larva will contribute to a better understanding of the conservation and functional diversity of neuropeptides in insects, and may shed light on evaluating the potential of AKH signal system as the target of novel insect control agents. 【Methods】The full-length cDNA sequence of BdAKH of B. dorsalis was cloned, and characterized with bioinformatics methods. The expression levels of BdAKH in different developmental stages (egg, 1st-3rd instar larvae, pupa, virgin female adult and male adult), and different tissues ［central nervous system, corpora cardiaca/corpus allatum (CC/CA), fat body, Malpighian tubules, midgut, hindgut, cuticle, ovary, testis and hemocytes］ of the late 3th instar larva of B. dorsalis were detected by qPCR. Immunohistochemistry technique was used to localize the neurons expressing BdAKH in the 3rd instar larva of B. dorsalis. RNAi combined with biological observation was used to analyze the regulation of BdAKH on the growth and development of B. dorsalis larva.【Results】The full-length cDNA sequence of BdAKH (GenBank accession no. KY073319) of B. dorsalis was cloned. This cDNA of 572 bp contains an open reading frame (ORF) of 252 bp, which encodes 83 amino acid residues. BdAKH of B. dorsalis has conserved structure that consists of one mature peptide (QLTFSPDWamide). The expression levels of BdAKH were higher in adult. BdAKH was mainly expressed in the CC/CA of the late 3rd instar larva. Compared with the control group (dsGFP), BdAKH knockdown in the 3rd instar larva of B. dorsalis caused a delay in pupation and decreased pupation rate, while the pupal weight and phenotype had no remarkable difference. 【Conclusion】AKH plays important roles in regulating the larval growth and development of B. dorsalis, which could be viewed as new targets of novel insect control agents.

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Analysis of the adult antennal transcriptome and olfaction-related genes of Pieris rapae (Lepidoptera: Pieridae)

XUE Zeng-Sheng, YAN Xi-Zhong, ZHAO Jing-Yu, SONG Cheng-Fei, LIU Dan, WANG Han, HAO Chi, MA Li

Acta Entomologica Sinica 2023, 66 (5): 642-652. DOI: 10.16380/j.kcxb.2023.05.005

Abstract （270）

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【Aim】To establish the antennal transcriptome database of the Pieris rapae adult, so as to deeply mine the gene data of P. rapae by using bioinformatics and molecular biology methods.【Methods】High-throughput sequencing platform Illumina NovaSeq 6000 was used to perform antennal transcriptome sequencing, sequence assembly, functional annotation and differentially expressed gene analysis of P. rapae adults. qRT-PCR was used to verify nine differentially expressed olfaction-related genes including PrapOR1, PrapOR2, PrapOR5, PrapOBP1, PrapOBP4, PrapOBP5, PrapSNMP1, PrapSNMP2 and PrapSNMP3.【Results】By sequencing of the antennal transcriptome of adults of P. rapae, a total of 17.65 GB sequencing data (NCBI registration number: PRJNA869896) were obtained. A total of 116 317 transcripts were obtained through filtering and sequence splicing. Then, 43 390 unigenes were obtained by Corset hierarchical clustering. BUSCO evaluation showed that the stitching quality had good integrity and high accuracy. The databases with the largest number of unigene annotations in a descending order were NT, NR, Pfam, GO, Swiss-Prot, KEGG and KOG/COG. Furthermore, 176 olfaction-related genes were screened by gene functional annotation analysis, among them 19 genes were differentially expressed, including 15 genes highly expressed in female adult antennae and four genes highly expressed in male adult antennae. qRT-PCR verification results showed that PrapOR1 and PrapOR2 were highly expressed in male adult antennae, PrapOR5, PrapOBP1, PrapOBP4, PrapOBP5, PrapSNMP1, PrapSNMP2 and PrapSNMP3 were highly expressed in female adult antennae, indicating the consistency with the transcriptome sequencing results.【Conclusion】In this study, a transcriptomic database of adult antennae of P. rapae was established, the olfaction-related genes were screened and the differential expression of olfaction-related genes was analyzed. The results provide a theoretical basis for further studies on the gene function and olfactory molecular mechanism of P. rapae.

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Effects of chronic exposure to LC₂₀ of dinotefuran on the growth and development of Sitobion avenae (Hemiptera: Aphididae)

SHI Hai-Chun, JI Qin-Long, MA Jian-Xiong, LIANG Yu-Ting, LI Guang-Kuo, ZHANG Hai-Ying, LIU Yong-Gang

Acta Entomologica Sinica 2023, 66 (5): 685-693. DOI: 10.16380/j.kcxb.2023.05.009

Abstract （264）

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【Aim】 The effects of chronic exposure to the sublethal concentration (LC₂₀) of dinotefuran on the growth and development of Sitobion avenae were studied in order to provide a theoretical basis for the scientific use of dinotefuran to control S. avenae and delaying the development of the resistance to the pesticide and extending the useful life of pesticide. 【Methods】 The LC₂₀of dinotefuran to the 3rd instar nymphs of S. avenae was determined by using the leaf-dip method andusedforchronic exposure on S.
avenae for 15 generations. The resistance ratio of S. avenae to dinotefuran was determined, the developmental duration, reproduction and survival rates of S. avenae of two successive generations which were raised with wheat seedlings in test tube were recorded, and the body length, body width and body weight of adults of F₀ generation were measured. The differences in the body length, body width, body weight, survival rate, adult longevity and number of offspring produced between lowly resistant strain of various generations and the susceptible strain were analyzed by population specific life table and DPS software. 【Results】 After chronic exposure to LC₂₀ of dinotefuran for 15 generations, the resistance of S. avenae reached low level (6.54-fold). The developmental duration of the 2nd, 3rd and 4th instar nymph of F₀ generation of the lowly resistant strain was significantly longer than that of the susceptible strain, and the body length, body width and body weight of F₀ generation of adults of the lowly resistant strain were significantly increased, but the number of offspring produced per adult and adult longevity of F₀ generation of the lowly resistant strain were significantly reduced or shortened as compared to those of the susceptible strain. The adult survival rate, number of offspring produced per adult and adult longevity of F₁ generation of the lowly resistant strain were significantly reduced, the 2nd instar nymphal duration and nymphal duration of F₁ generation of the lowly resistant strain were significantly shortened as compared to those of the susceptible strain. The net reproductive rate (R₀), intrinsic rate of increase (R_m) and finite rate of increase (λ) of F₀ and F₁ generations of the lowly resistant strain were significantly lower than those of the susceptible strain, while the population doubling time (DT) of F₀ and F₁generations and the mean generation time (T) of F₁ generation of the lowly resistant strain were significantly prolonged as compared to those of the susceptible strain. 【Conclusion】 Chronic exposure to LC₂₀ of dinotefuran results in the increase in the resistance of S. avenae to dinotefuran and individual size of adults of F₀ generation, while inhibits the longevity and fecundity of F₀ and F₁ generations of S. avenae.
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Rice pests: Research progresses and prospects

LI You-Zhi, FANG Ji-Chao

Acta Entomologica Sinica 2024, 67 (4): 443-455. DOI: 10.16380/j.kcxb.2024.04.001

Abstract （264）

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Rice, as a major staple crop in China, is directly threatened by disease and pest infestations, which jeopardize its safe production. Rice pests are diverse, and their outbreak mechanisms are complex, making the development of green control technologies challenging. Indepth research into rice pest monitoring and early warning technologies, developmental and reproductive regulation mechanisms, chemical communication mechanisms, and novel control technologies not only helps elucidate the outbreak mechanisms of rice pests but also provides new effective control targets and techniques for integrated pest management. In recent years, Chinese scholars have made significant progress in the field of rice pest research, gaining important achievements in multiple research directions, and some recent research findings were presented in this special issue. In this article, we outline the latest progresses in rice pest research at home and abroad, introduce the main research contents of this special issue, and propose the following three research directions worthy of further attention: (1) intelligent monitoring and early warning of rice pests; (2) mechanisms and evolution patterns of rice pest outbreaks; and (3) exploration of green control targets for rice pests and the construction and application of sustainable control systems.

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Analysis on the stability and influencing factors of protogyny of Spodoptera frugiperda (Lepidoptera: Noctuidae)

BI Si-Jia, HU Ben-Jin, HU Fei, XU Ting-Ting, XU Li-Na

Acta Entomologica Sinica 2023, 66 (9): 1201-1209. DOI: 10.16380/j.kcxb.2023.09.007

Abstract （262）

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【Aim】 Protandry was more common in studies on developmental duration of sex dimorphic insects, and protogyny was less reported. The fall armyworm, Spodoptera frugiperda is a severe migratory pest on maize, and there is a phenomenon of protogyny in its developmental duration. The purpose of this study is to clarify the stability of this phenomenon and explore its influencing factors, so as to provide a theoretical basis for the accurate monitoring and early warning of S. frugiperda.【Methods】 The growth and development of S. frugiperda under three photoperiods (16L∶8D, 14L∶10D and 8L∶16D) and three food conditions (maize leaves, peanut leaves and artificial diet) were analyzed, and the ovaries of S. frugiperda reared under different photoperiods and food conditions were dissected. Moreover, the growth and development of Mythimna separata, S. litura and S. frugiperda in Noctuidae were compared to evaluate whether the protogyny was the commonness of Noctuidae insects with migratory habits.【Results】 In the comparison of three Noctuidae migratory insects, only the female adults of S. frugiperda eclosed significantly earlier (1.28 d ahead) than the male adults, and the eclosion phenomenon was stable under different photoperiods and food conditions, and only showed a weakening trend when S. frugiperda fed on peanut leaves. It was found that the ovaries of the newly eclosed adults of S. frugiperda were always immature under different photoperiods and food conditions, and did not change with external conditions. The development of female pupa of S. frugiperda was significantly faster than that of male pupa, which was the main reason for the difference in eclosion time between the two sexes of S. frugiperda, and the difference was positively correlated with the pupal weight of the two sexes: Compared with the female pupal weight, the male pupal weight of S. frugiperda increased significantly by 9.88%.【Conclusion】 The phenomenon of protogyny of S. frugiperda is relatively stable. Photoperiod and food will not change this phenomenon, but will affect the difference of eclosion time between the two sexes, and protogyny is not the commonness of Noctuidae insects with migratory habits.

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Effects of light intensity on the oviposition preference of Grapholita molesta (Lepidoptera: Tortricidae)

YANG Xiao-Fan, JIAO Hui-Tan, LI Xu-Zhao, LU Zi-Yun, RAN Hong-Fan, MA Ai-Hong, WEI Guo-Shu, LI Jian-Cheng

Acta Entomologica Sinica 2023, 66 (7): 918-924. DOI: 10.16380/j.kcxb.2023.07.006

Abstract （257）

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【Aim】Grapholita molesta is an important and frequent pest of fruit trees. This study aims to investigate the roles of light intensity on the oviposition preference of G. molesta, and to further reveal the dim-light vision ability in G. molesta. 【Methods】The numbers of eggs of G. molesta laid on leaves on the sunny side and shaded side in the peach tree canopy were investigated in spring, summer and autumn, and the difference in light intensity between the sunny side and shaded side at sunset was measured. Light-dark two-choice experiments were carried out indoor to test the oviposition preference behavior response of G. molesta adults to light intensity. 【Results】 In spring, summer and autumn, G. molesta adults preferred to lay eggs on leaves on the sunny side in the peach tree capony with significantly higher light intensity, the numbers of eggs laid on the sunny side were 4.24, 9.30 and 5.82 times as high as those on the shaded side, respectively. In the light-dark two-choice experiments, G. molesta adults preferred to lay eggs to light than to dark, with the oviposition selection rates of 87.48%, 83.68%, 82.92%, 80.08% and 84.84%, respectively, under 10 000, 100, 1 and 0.01 lx and natural light conditions. The oviposition preferences between to strong light and to weak light revealed that when the light contrast (strong light/weak light) was 10 and 2, respectively, G. molesta adults showed a preference to strong light under 10 000, 100, 1 and 0.01 lx and natural light conditions. Moreover, this preference to strong light did not decrease significantly with the decrease of light intensity, and the oviposition selection rates were higher than 75%.【Conclusion】 Light intensity can affect the oviposition preference of G. molesta adults. Female adults show obvious oviposition preference to strong light, and can still discriminate well the difference in light intensity even under dim light, exhibiting a well dim-light vision ability. The results provide a basis for new physical trapping techniques based on visual behavior regulation.

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Regulatory mechanism of intestinal microbial homeostasis in insects

SONG Yang, FAN Lin-Lin, SHENTU Xu-Ping, YU Xiao-Ping

Acta Entomologica Sinica 2023, 66 (10): 1404-1414. DOI: 10.16380/j.kcxb.2023.10.013

Abstract （255）

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A stable intestinal microbial internal environment is the result of the interaction between intestinal microbes and intestinal immune response. During the continuous feeding, the species and number of insect intestinal microbes constantly change, so a complex and dynamic homeostatic mechanism is formed between intestinal microbes and intestinal epithelial cells. Insect intestinal epithelial cells can sense beneficial and harmful conditions and use immunoregulatory pathways for dynamic regulation of microbial population homeostasis, such as the dual oxidase-reactive oxygen species (Duox-ROS) system and immunodeficiency (Imd) signaling pathways, which can sense the changes in the number of intestinal microbies and participate in the regulation of intestinal microbial homeostasis. In addition, the intestinal microbes can also indirectly play a role in homeostatic regulation by releasing corresponding effectors to regulate the behavior of the flora through quorum sensing (QS). Thus, in this article, we reviewed the roles of physical defense, immune signaling pathways and QS in the maintenance of insect intestinal microbial homeostasis, which will deepen the understanding of the interactions between intestinal tissues and intestinal microbes. In the future, we will continue to reveal the regulatory mechanisms of microbial homeostasis in more species of insects and the relationship between the regulatory mechanisms. In addition, new pesticides will be designed and developed to alter the homeostasis of intestinal microbes based on the regulatory mechanisms, which will provide new targets and ideas for the pest control.

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Vitellogenin determines the abundance of the symbiotic bacterium Rickettsia in Bemisia tabaci (Hemiptera: Aleyrodidae) by regulating autophagy

SUN Xiang, LIU Bing-Qi, CHEN Zhan-Bo, LI Huan, LI Chu-Qiao, HONG Ji-Sheng, LUAN Jun-Bo

Acta Entomologica Sinica 2023, 66 (10): 1302-1310. DOI: 10.16380/j.kcxb.2023.10.004

Abstract （251）

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【Aim】 To explore the molecular mechanism by which vitellogenin (Vg) regulates the abundance of the symbiotic bacterium Rickettsia in Bemisia tabaci. 【Methods】 Female adult of B. tabaci MEAM1 was microinjected with dsRNA to conduct RNAi of BtVg, the expression levels of BtVg and the autophagy gene BtAtg8 in the female adult were detected by qRT-PCR, the mortality rate of female adults was recorded, and the abundance of Rickettsia in the female adult was quantified by qPCR. The localization and expression of BtVg and BtAtg8 in ovarioles and the abundance of Rickettsia in the ovarioles and midguts of the female adult were examined by immunofluorescence microscopy. After the autophagy induction by feeding the female adult of B. tabaci MEAM1 with the artificial diet containing rapamycin (10 μmol/L), the expression and localization of BtAtg8 in ovarioles were investigated by immunofluorescence microscopy and the abundance of Rickettsia in ovaries was detected by qPCR. 【Results】 The expression levels of BtVg and BtAtg8 in the female adult of B. tabaci MEAM1 were significantly decreased and significantly increased, respectively, the mortality rate of female adults of B. tabaci MEAM1 was significantly increased, the abundance of Rickettsia in the female adult of B. tabaci MEAM1 was significantly decreased, the expression levels of BtVg and BtAtg8 in ovarioles were obviously decreased and obviously increased, respectively, and the abundance of Rickettsia in the ovarioles and midgut obviously decreased at 3 d after microinjection of dsBtVg compared to the control (microinjected with dsGFP). The expression level of BtAtg8 in the ovarioles of the female adult of B. tabaci MEAM1 was increased significantly at 5 d after feeding with the artificial diet containing rapamycin (10 μmol/L), and the abundance of Rickettsia in the ovarioles of the female adult of B. tabaci MEAM1 was significantly decreased at 3 and 5 d after feeding with the artificial diet containing rapamycin (10 μmol/L) compared with the control fed with the artificial diet containing DMSO. 【Conclusion】 These results suggest that BtVg can protect Rickettsia from degradation by autophagy, and demonstrate the role of BtVg in regulating the abundance of Rickettsia in B. tabaci.

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Research progress in protein-carbohydrate regulation in insects based on geometric framework model

SUN Shao-Lei, JING Xiang-Feng

Acta Entomologica Sinica 2023, 66 (5): 713-722. DOI: 10.16380/j.kcxb.2023.05.012

Abstract （250）

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Protein and carbohydrate are two essential nutrients for insects. Protein is the source of amino acids for insect growth, while carbohydrate is the source of energy for activity. These two nutrients play important roles in insect growth, development and reproduction. In the nature, all insects experience heterogeneous nutritional landscapes, and the contents of proteins and carbohydrates in their food including plants or preys generally vary upon species, tissues or developmental stages. Thus, insects may have some strategies to find the food that contains the proper nutritional composition in their living environment so as to make their growth and development reach the optimal status. Geometric framework model has been demonstrated to be a powerful tool to investigate nutritional physiological regulation mechanisms in insects. This model has been extensively used in how insects coordinate different nutrients in food to achieve the balance of life processes, such as growth, development and reproduction. In herbivores, it is shown that the protein/carbohydrate ratio in food combining with environmental factors can affect the growth and development, as well as the immune response of insects. In predatory and social insects, it is shown that they can strictly regulate the intake of protein and carbohydrate nutrients to meet their needs. In model insects, it is shown that protein/carbohydrate ratio in food may have a balancing effect on lifespan and reproduction in insects. In this review, we introduced the working principle of geometric framework model and systematically summarized its application in insects, aiming to provide new ideas for the study of insect nutrition physiology and ecology.

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Construction of RNA interference system of nAChR-α5 gene in Aedes albopictus (Diptera: Culicidae) and its role in haedoxan A resistance

REN Yun-Hao, HAO Huan-Huan, ZUO Ya-Yun, PEI Ya-Kun, HU Zhao-Nong

Acta Entomologica Sinica 2023, 66 (5): 676-684. DOI: 10.16380/j.kcxb.2023.05.008

Abstract （248）

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【Aim】To explore whether the nicotinic acetylcholine receptor α5 (nAChR-α5) subunit in Aedes albopictus is a potential target for haedoxan A (HA), so as to provide a reference for the effective control of A. albopictus. 【Methods】 The coding sequence (CDS) of nAChR-α5 gene of A. albopictus was cloned by PCR and phylogenetic tree was constructed. RT-qPCR was used to detect the expression level of nAChR-α5 in A. albopictus at different developmental stages (1st-4th instar larvae, pupa and female adult without blood feeding). The expression level of nAChR-α5 in the 2nd instar larva of A. albopictus was knocked down by chitosan/dsRNA nanoparticle-mediated RNAi technology. The susceptibility of the 3rd instar larva of A. albopictus to HA ［LC₃₀ (0.3 mg/L) and LC₅₀ (0.4 mg/L)］ after RNAi was determined by bioassay. 【Results】 The CDS of A. albopictus nAChR-α5 is 1 296 bp in length, encoding 431 amino acids with a typical cysteine loop (Cys-loop) of nAChR. Protein sequence alignment and phylogenetic tree showed that nAChR-α5 of A. albopictus had the highest homology and closest relationship with nAChR-α5 of A. aegypti. The expression level of nAChR-α5 in the 4th instar larva was the highest, followed by that in the female adults of A. albopictus. At 24 h after feeding chitosan/dsnAChR-α5 nanoparticles (the concentration of dsRNA was about 0.3% w/w), the interference efficiency of chitosan/dsnAChR-α5 nanoparticles on nAChR-α5 was the highest, reaching 70% in the 2nd instar larva of A. albopictus. The mortalities of the 3rd instar larvae of A. albopictus in nAChR-α5 knockdown group under treatment of HA at LC₃₀ and LC₅₀ were significantly reduced by 9.89%-15.45% as compared with those in the blank control fed with the diet without dsRNA and negative control fed with the diet containing chitosan/dsGFP nanoparticle, indicating that the susceptibility of A. albopictus to HA was significantly reduced by knockdown of nAChR-α5. 【Conclusion】nAChR-α5 of A. albopictus may be one of the potential targets of HA, and HA may affect nerve conduction by interfering with the function of nAChR-α5 of A. albopictus.

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Relationship between the symbiotic microbial community and insecticide resistance in wild Anopheles sinensis (Diptera: Culicidae)

QIU Xin, MENG Chen, WANG Ming-Bin, CHEN Bin, ZHANG Yu-Juan

Acta Entomologica Sinica 2023, 66 (9): 1183-1191. DOI: 10.16380/j.kcxb.2023.09.005

Abstract （245）

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【Aim】 To investigate the relationship between the symbiotic microbial communities in Anopheles sinensis and the insecticide resistance of An. sinensis in different regions of the wild environment. 【Methods】 Wild female adults of An. sinensis were collected from Chongqing, Yunnan, and Anhui in China. WHO standard in vitro bioassay and 0.05% deltamethrin impregnated paper were used to conduct insecticide susceptibility tests on the female adults of An. sinensis, classifying them as insecticide-sensitive (FS) or insecticide-resistant (FR) to perform high-throughput sequencing of the whole genomes through Illumina Hiseq 2000 platform. The sequences of 16S rRNA and 18S rRNA genes were aligned to identify symbiotic microbiota in the FS and FR An. sinensis. Alpha diversity analysis, beta diversity analysis, clustering analysis, principal coordinates analysis (PCoA) and analysis of symbiotic microbial community differences were conducted. 【Results】 A total of 3 284 species of 52 genera of 14 phyla of symbiotic microbiota were identified from the female adults of the FS and FR wild An. sinensis from Chongqing, Yunnan and Anhui. The diversity difference and community richness of the FR wild An. sinensis female adults from Anhui were the highest, and those of the FS wild An. sinensis female adults from Chongqing were the lowest. The symbiotic microbial communities in the female adults of wild An. sinensis were first clustered by region, and the diversity of the symbiotic microbial communities in the female adults of An. sinensis from Chongqing and Yunnan were more similar. A total of 10 strains including two strains of Cyanobacteria, three strains of Halobacteria, one strain of Haliangium, three strains of Ruminococcaceae and one strain of Streptococcus of bacteria in the symbiotic microbiota in the FR wild An. sinensis female adults were more abundant.【Conclusion】 The symbiotic microbial communities of the wild An. sinensis exhibit regional and resistance differences. The identified symbiotic microbiota play a positive role in the insecticide resistance of An. sinensis. The results of this study provide insights into understanding the insecticide resistance of An. sinensis.

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Gene cloning, polyclonal antibody preparation, and expression pattern of m⁶A methyltransferase in Apis mellifera (Hymenoptera: Apidae)

WU Ying, LIU Zhi-Tan, ZHAO Hao-Dong, GUO Si-Jia, LIU Xiao-Yu, ZHANG Yi-Qiong, FENG Pei-Lin, ZHAO Hong-Xia, XU Xi-Jian, CHEN Da-Fu, FU Zhong-Min, GUO Rui ,

Acta Entomologica Sinica 2023, 66 (7): 885-895. DOI: 10.16380/j.kcxb.2023.07.003

Abstract （238）

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【Aim】 This study aims to offer reference and foundation for continuous and further study on RNA m⁶A methyltransferase 14 (METTL14) gene of Apis mellifera AmMETTL14 through cloning AmMETTL14, analyzing the physicochemical properties and molecular characteristics of AmMETTL14, detecting the expression pattern of AmMETTL14 in different developmental stages and various tissues of workers, and preparing the polyclonal antibody to AmMETTL14. 【Methods】 The CDS of AmMETTL14 in A. mellifera was amplified by PCR followed by Sanger sequencing validation. Bioinformatic analysis and construction of phylogenetic tree of AmMETTL14 were conducted using relevant bioinformatics software. Inducible expression of AmMETTL14 fusion protein was performed through prokaryotic expression system, followed by immunization of New Zealand white rabbits to prepare the polyclonal antibody, and the titer and specificity of the antibody were evaluated by ELISA and Western blot, respectively. RT-qPCR was used to detect the relative expression level of AmMETTL14 in the egg, larva, prepupa, pupa and adult worker, and seven tissues including antenna, venom gland, brain, midgut, hypopharyngeal gland, fat body and cuticle of the newly emerged adult worker.【Results】 The CDS of AmMETTL14 of A. mellifera was successfully cloned. The molecular formula of AmMETTL14 is C₁₉₅₇H₃₁₁₃N_567O589S₁₅, the molecular weight is about 44.49 kD, the liposoluble coefficient is 79.97, the theoretical isoelectric point is 8.58, and the average hydrophilic coefficient is -0.59. AmMETTL14 contains no typical transmembrane domain and signal peptide, and is simultaneously located to the nucleus, mitochondria and cytoplasm. METTL14s in A. mellifera, A. cerana cerana, A. laboriosa, A. cerana, A. dorsata, A. florae, Bombus terrestris, Vespa mandarinia, B. impatien and Drosophila melanogaster contain the structural domain MT-A70 and three same conserved motifs. AmMETTL14 and METTL14 of A. laboriosa had the highest amino acid sequence identity (65.60%) and the closest relationship. The prepared polyclonal antibody to AmMETTL14 had high titer (more than 512 K) and strong specificity. The expression levels of AmMETTL14 in the 7- and 8-day-old prepupae and eggs were similar and significantly higher than that in the 3-day-old larva, that in the 12-day-old pupa was significantly higher than those in the egg, larva and prepupa, and those in the 6-, 12- and 15-day-old adult workers were significantly higher than that in the 1-day-old adult worker. Additionally, the expression levels of AmMETTL14 in the brain and hypopharyngeal gland were similar to that in the antenna, and significantly higher than those in the venom gland, midgut, fat body and cuticle of the newly emerged adult worker. 【Conclusion】 This study result indicates that AmMETTL14 may be a hydrophilic, non-transmembrane and intracellular protein, AmMETTL14 plays potential regulatory role in larval growth and development, and the prepared polyclonal antibody to AmMETTL14 has high titer, sensitivity and specificity, laying a foundation for further exploring the function of AmMETTL14 and the involved epigenetic regulation mechanisms.

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Community composition and functional gene annotation of the symbiotic microbes in Ips nitidus (Coleoptera: Scolytinae)

LIU Cai-Xia, LI Gang, LIANG Ling-Yu, HAN Fu-Zhong, WANG Zheng, WANG Hui-Min, LÜ Quan

Acta Entomologica Sinica 2023, 66 (10): 1329-1342. DOI: 10.16380/j.kcxb.2023.10.007

Abstract （238）

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【Aim】To reveal the community composition and functional characteristics of the symbiotic microbes in Ips nitidus. 【Methods】Metagenomics and correlation network analysis were conducted on the symbiotic fungi and bacteria in the gut and other tissues of I. nitidus from Maixiu Nature Reserve in Qinghai Province, Northwest China to compare the community composition of the symbiotic fungi and bacteria in the gut and other tissues of I. nitidus, to analyze the interrelationships of the microbial communities and to annotate the functional genes of the symbiotic microbes by non-redundant protein sequence alignment method. 【Results】A total of 3 520 species of symbiotic microbes were found in the gut and other tissues of I. nitidus. Fungi and bacteria possessed the highest numbers of species (accounting for 23.21% and 69.01% of all species, respectively), with the average relative abundance of 9.69% and 13.79%, respectively. For fungal symbionts, Erysiphales showed higher relative abundance and species diversity in other tissues than in the gut, and Saccharomycetales showed lower relative abundance and species diversity in other tissues than in the gut. Ophiostomatoid fungi in other tissues showed higher species diversity than those in the gut (16 species of 6 genera, and 13 species of 5 genera, respectively). The average relative abundance of ophiostomatoid fungi in other tissues and gut occupied 0.016% and 0.013%, respectively. The relative abundance and species diversity of Enterobacterales in other tissues were higher than those in the gut. Enterobacter, Erysiphe, Rhizophagus and Wolbachia were the core genera in the gut and other tissues. Some communities of fungi and bacteria showed opposite interrelationships in the gut and other tissues, suggesting that there may be complex interactions between the symbionts in I. nitidus. A total of 7 010 and 6 483 functional genes were identified from symbiotic fungi and bacteria, respectively. The number of functional genes related to xenobiotics biodegradation and metabolism in bacteria was higher than that in fungi. However, 11 pathways such as mRNA surveillance pathway, propanoate metabolism, ubiquitin-mediated proteolysis and so on had more significant differential genes in the gut than in other tissues. The annotation results for functional genes related to limonene degradation and sterol synthesis showed that bacteria may degrade limonene significantly compared with fungi, but fungi may play a more crucial role in promoting sterol biosynthesis than bacteria. A total of 74 functional genes of ophiostomatoid fungi are mainly involved in oxidative phosphorylation, metabolic pathway and amino acid metabolism. Moreover, ophiostomatoid fungi were of higher diversity in other tissues and mainly distributed in Ophiostoma, etc. 【Conclusion】There are some differences in the community composition, diversity and function of the symbiotic microbes in the gut and other tissues of I. nitidus. Enterobacter, Erysiphe, Rhizophagus and Wolbachia are the most important core flora, and they might play an important role in the community assembly.

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