【Aim】 This study aims to further understand the symbiotic relationship between auchenorrhynchan insects of the order Hemiptera and endosymbionts by investigating the diversity and functions of obligate and facultative symbiotic bacteria in bacteriomes, fat bodies and other related tissues of adult Tettigetta isshikii at the ultrastructural and genomic levels. 【Methods】 Field-collected female and male adults of T. isshikii were investigated to clarify the distribution of symbiotic bacteria Karelsulcia, Hodgkinia and Wolbachia in the bacteriomes, fat bodies, ovaries, spermathecae, salivary glands, conical segment, filter chamber and gut of female adults, and testes of male adults through transmission electron microscopy and fluorescence in situ hybridization. Metagenomic sequencing, assembly and functions by genome annotation of symbiotic bacteria in the bacteriomes and fat bodies of female adults, and testes of male adults of T. isshikii were conducted. The phylogenetic relationships of Wolbachia in T. isshikii and other insects were determined using maximum-likelihood and Bayesian inference methods to determine the phylogenetic position of Wolbachia. 【Results】 The obligate symbiotic bacteria Karelsulcia and Hodgkinia are harbored in the bacteriomes of female adults of T. isshikii, and the facultative symbiotic bacterium Wolbachia, belonging to the supergroup F, was harbored not only in the cytoplasm and nuclei of the epithelial cells of testicular follicles but also in the nuclei of sperms of male adults and fat bodies of female adults. Genome annotation analysis revealed that genes of Karelsulcia and Hodgkinia were involved in the synthesis of essential amino acids and vitamins for the host cicada, while genes of Wolbachia were involved in riboflavin metabolism, heme pathway, and biosynthesis of purine and pyrimidine. The duplication of Wolbachia occured within the nuclei of sperms, which ultimately may lead to the rupture of nuclei. Phylogenetic relationship revealed that this Wolbachia belongs to the F supergroup and was closely related to the Wolbachia harbored in other arthropods and nematodes. 【Conclusion】 This study clarified the potential nutritional functions of symbionts Karelsulcia and Hodgkinia in the bacteriomes of T. isshikii adults, and elucidated a unique phenomenon that Wolbachia may have both beneficial and detrimental effects for the host insects. The results of this study contribute to a further understanding of the symbiotic relationship and complex co-evolution between Cicadidae and symbiotic bacteria.

 Aphids (superfamily Aphidoidea) are a group of globally distributed piercing-sucking insects, of which there are approximately 5 000 species. Some species such as cereal aphids, the cotton aphid Aphis gossypii, and the peach-potato aphid Myzus persicae threaten agricultural and forestry production. Typically, aphids absorb sap from plant phloem that induces a reduction in crop photosynthate accumulation, and are capable of transmitting more than half of known plant viruses. Furthermore, parthenogenetic reproduction and wing dimorphism facilitate rapid expansion and habitat transfer for aphid population. The strong ecological adaptability of aphids is inextricably linked to the population outbreak and infestation. It remains challenging for developing precise and effective control technologies for aphids due to strong resistance to pesticides caused by short generation time and parthenogenetic reproduction of aphids, and the non-target pests for Bt crops. In recent years, Chinese scientists have made a series of breakthroughs in the aphid genome divergence, the regulation of wingform and reproductive plasticity, salivary protein-mediated mechanisms of feeding and virus transmission, and insect-microbe symbiotic co-adaptation, leading to the development of pest control technologies like RNAi-based breeding for aphid resistance and ecological control by natural enemies. In this article, we summarized the latest advancements in this field in China, outlined the core scientific contributions of included papers, and provided a forward-looking perspective on future research directions such as the functional analysis of salivary glands at the single-cell level, the mechanisms of non-persistent virus transmission, epigenetic regulatory networks, and pest control technologies based on insect-microbe symbiosis, aiming to provide theoretical and practical foundations for scientific research and aphid control.

Insects are closely associated with human production and life, and therefore entomological research has important theoretical significance and practical value. Insects are good materials to study biological questions because they are easily bred in a large number. The rapid development of molecular biology techniques has greatly promoted the process of entomological research. The success of the transcriptome sequencing and gene editing technologies has broken the boundary of the model species and the non-model species, providing techniques for the study of various important agricultural pests. We need to consider the important scientific questions according to the needs of production practice and the existing theories, promote entomological research progress by using various research methods and techniques, and clarify special scientific questions in the field of entomology and common scientific questions in the field of biology as well.  

【Aim】 To elucidate the effects of Cnidium monnieri on ladybird conservation and aphid control during the whole growth period of wheat and maize. 【Methods】 The occurrence amounts of ladybirds and aphids in wheat and maize fields with C. monnieri planted and the control with pure crops planted were systematically investigated and counted by visual observation throughout the year, and the spatio-temporal correspondence between ladybirds and aphids was clarified. 【Results】 Planting C. monnieri significantly increased the occurrence amounts of natural enemy ladybirds in wheat and maize fields, which in turn significantly reduced the occurrence amount of aphids. In 2020 and 2022, the peak numbers of ladybirds in wheat fields with C. monnieri planted were 25.33 and 9.00 individuals/m², respectively, which were significantly higher than those in the control wheat fields (11.73 and 5.33 individuals/m², respectively). Concurrently, the peak total numbers of aphids in wheat fields with C. monnieri planted were 786.00 and 817.33 individuals/100 plants, respectively, which were significantly lower than those in the control wheat fields (932.67 and 1 133.33 individuals/100 plants, respectively). During the same period, the peak numbers of ladybirds in maize fields with C. monnieri planted were 77.53 and 109.33 individuals/100 plants, respectively, which were significantly higher than those in the control maize fields (50.67 and 77.33 individuals/100 plants, respectively). In 2020, no significant difference was shown in the peak number of Rhopalosiphum maidis in maize fields between treatment and the control. However, on one week after the peak period of R. maidis, the individual number of R. maidis per 100 plants in maize fields with C. monnieri planted was 2 209.33, significantly lower than that in the control maize fields (5 926.67). In 2022, the individual number of R. maidis per 100 plants in maize fields with C. monnieri planted was 13 533.30, significantly lower than that in the control maize fields (30 600.00). 【Conclusion】 Planting C. monnieri in wheat-maize rotation cropping system can conserve natural enemy ladybirds throughout the year, effectively suppressing the occurrence of wheat aphids and R. maidis, thereby exerting a good ecological pest control effect.

【 Aim 】 To investigate and analyze the changes in the structural composition, functional diversity and stability of terrestrial insect communities in different wetland types in Yinchuan, Northwest China. 【 Methods 】 Four wetland habitats including Yellow River wetland (HH), Mingcui Lake wetland (MCH), Luhuatai wetland (LHT) and Shuidonggou wetland (SDG) were selected based on the experimental design, and sampled from May to October, 2016. Insects were collected by chessboard sweeping and pitfall trapping approaches. Insect community structure diversity analysis, principal component analysis and cluster analysis were conducted based on the survey data. 【 Results 】 A total of 38 668 insects belonging to 370 species, 97 families and 13 orders were collected from the four wetland habitats in Yinchuan. Among them, Diptera, Homoptera, and Hymenoptera were the dominant groups in all the four habitats. Phytophagous insects accounted for the largest proportion in the family and species level of the insect communities among the four wetlands. The individual number showed a significantly negative correlation between the phytophagous and the neutral insects (Ph - Ne) in the four habitats (P<0.01). In the MCH habitat, the individual number showed a significantly positive correlation between the phytophagous and the predatory insects (Ph - Pr) (P<0.05), while a significantly negative correlation between the neutral and the predatory insects (Ne - Pr) (P<0.01). Additionally, in the LHT habitat, the individual number showed a significantly negative correlation between the neutral and the predatory insects (Ne - Pr) (P<0.05). Finally, the individual number in other combinations among the four functional groups did not show any significant correlation in all the four habitats. The predatory species group was the main component that affected the composition of the insect community based on principal component analysis (PCA). For the diversity analysis of the same functional group in the four habitats, there was a significant difference between the predatory (Pr) and the parasitic (Pa) functional groups based on the Simpson index (P<0 . 05), while there was no significant difference between the phytophagous (Ph) and the neutral (Ne) functional groups based on the Simpson index (P>0.05). Based on the Shannon - Wiener index, there was no significant difference among the neutral (Ne) functional groups in the four habitats (P>0.05), while there was a significant difference among the neutral (Ne) functional groups in the four habitats based on Pielou evenness index (P<0.05). Based on the Shannon - Wiener indices for the other three functional groups, there were significant differences among the four habitats (P<0.05), while they had no significant differences in the Pielou evenness index (P>0.05). The cluster analysis showed that the four types of wetlands were divided into two categories based on the characteristic index of insect communities, the first was permanent wetlands including HH and MCH, and the second was seasonal wetlands including LHT and SDG. Based on the stability index, the highest stability was found in the MCH habitat. The most stable periods for insect communities in different habitats were in May and September annually. 【 Conclusion 】 Diptera and Hymenoptera are the dominant groups in different wetland habitats in Yinchuan, and can be used as environmental indicators. The insect communities in the permanent lake wetland show the highest stability. The diversities of the insect communities in different habitats change with the seasons, and the most stable periods are in May and September annually. How the climatic factors and environmental factors drive the diversity to change and what factors affect the stability of insect communities in different wetlands remain to be studied.

The elevated global colony losses of the Western honey bee, Apis mellifera, have drawn much attention in beekeeping and scientific communities. The ectoparasite Varroa destructor and Deformed wing virus (DWV) are regarded as the two key biotic threats to colony health. Irrespective of the long-time existence in colonies, their synergistic impacts on honey bee health, which are far more severe than the harms caused by separate individuals, were not intensively studied until the recent decade. These synergistic effects include: (1) DWV replicates on V. destructor and transmits with the mites; (2) DWV can be directly transmitted into host hemolymph through mite feeding; (3) Highly virulent strains of DWV bias proliferation in A. mellifera populations with the co-occurrence of Varroa infestation; (4) V. destructor affects honey bee’s immunity and development, resulting in the impairment of host defence to viruses; (5) DWV-induced immunosuppression in hosts favors mite feeding and reproduction. The complex relationships among V. destructor, DWV and A. mellifera have become a typical model in the study of parasite-pathogen-host interactions. By summarizing the relevant researches in this field over the last decade, we aim to provide insights for further studies on colony losses and parasite-pathogen-host interactions.  

【Aim】 Epacromius coerulipes (Ivanov) is one of the most widely distributed grassland locusts. However, there is a lack of genomic resources. In order to obtain genetic data of E. coerulipes, this study conducted the transcriptome sequencing and analysis. 【Methods】 De novo assembly of the transcriptome was conducted using Illumina paired-end sequencing technology. 【Results】 In total, 63 033 unigenes with a mean length of 772 bp and an N50 length of 1 589 bp were obtained. Of these unigenes, 25 132(39.87%) unigenes were matched with the known proteins in the National Center for Biotechnology Information (NCBI) database, as determined by BLAST search, with 24 841, 16 490, 11 558 and 8 013 unigenes assigned to Nr database, Swiss-Prot, Gene Ontology (GO) and Clusters of Orthologous Groups (COG), respectively. In KEGG database, a total of 7 218 unigenes were assigned to 218 known pathways. Among these, 189 unigenes were involved in metabolic pathways of xenobiotics or drugs. In-depth analysis of the data showed that 213 unigenes were identified as potentially involved in the detoxification of xenobiotics, and 29 unigenes were identified as encoding insecticide target proteins. In addition, 5 696 simple sequence repeats (SSRs) were detected. 【Conclusion】 This study lays the foundation for further research on gene function analysis and molecular resistance mechanisms to insecticides in E. coerulipes.

【Aim】 As the main factors, the amplitude of temperature fluctuation and the change of population density affect life history traits and population dynamics of insects, and have received widespread attention. Previous studies have shown that there is a complex and significant interaction between temperature and population density, but most studies focus on constant temperature, which cannot reflect the effects of actual temperature changes in nature on insect populations. Therefore, we focused on Rhopalosiphum padi as one of major wheat pests worldwide in this study and explored the effects of temperature amplitudes and population density on the life history traits and population parameters of R. padi through the indoor simulation of field temperature fluctuations and population density. 【Methods】R. padi nymphs newly born within 4 h were treated under the conditions of different temperature amplitudes［(22±0), (22±6) and (22±12) ℃］ and population densities (1, 2, 4 and 8 individuals/tube), the development, survival, longevity and fecundity were observed daily, and the population parameters such as intrinsic rate of increase, net reproductive rate and generation time were calculated. 【Results】 At the low population density (1 individual/tube), compared with the constant temperature ［(22±0) ℃］, high temperature amplitude (22±12) ℃ prolonged the nymphal duration by 1.24 d, reduced the adult fecundity (total number of offspring produced per adult) by 19.1 individuals/adult, and decreased the intrinsic rate of increase and net reproductive rate by 0.10 d-1and 18.7, respectively, and prolonged the generation time by 1.86 d. Under the constant temperature ［(22±0) ℃］, compared with the low population density (1 individual/tube), the high population density (8 individuals/tube) reduced the adult fecundity by 24.2 individuals/adult, and the intrinsic rate of increase, net reproductive rate and generation time by 35.3 d-1, 0.05 and 0.22 d, respectively. As population density increased, the high temperature amplitude ［(22±12) ℃］ exerted a stronger inhibition effect on the nymphal development, intensively shortened the adult longevity, and intensively reduced the intrinsic rate of increase and net reproductive rate. However, high population density not only reversed some of the adverse effects of high temperature amplitude on the fecundity but also enhanced the nymphal survial. 【Conclusion】 The results of this study show the complex effects of temperature amplitude and population density on the life history traits and population dynamics of R. padi, suggesting that previous insect survival models based on constant temperature cannot accurately describe the real status of insects under temperature variations in nature. The results will improve the accuracy of predicting and forecasting the population dynamics of field pests and formulating control strategies under climate change.

As the most diverse group of animals on earth, insects are closely related to human production and activities, making entomological research both theoretically significant and practically valuable. In the past decade, the rapid development of novel methods and technologies has greatly promoted the research progress of entomological research. In this article, we provided a comprehensive overview of the applications of emerging methods and technologies in such fields as entomological morphological identification, molecular mechanism and pest management, focusing on the main contents of this special issue from seven aspects: Micro-computed tomography, RNA interference, gene editing, artificial intelligence-driven intelligent recognition, nanotechnology, regulation of insect-microorganism symbiotes, and olfactory behavior regulation. We also proposed the challenges faced by the large-scale application and sustainable development of these technologies, and prospected the future development trend.

【Aim】In order to more systematically reveal the transmission mode of banana bunchy top virus (BBTV) in the transmission vector Pentalonia nigronervos. 【Methods】Non-viruliferous P. nigronervos adults were allowed to acquire BBTV by feeding on infected plants of Musa acuminata AAA Groups, Cavendish cv. Baxi for 6, 12, 24, 36, 48 and 72 h. Then the expression levels of coat protein (CP) genes in these P. nigronervos adults were detected using PCR and qPCR to determine the virus acquisition time of non-viruliferous P. nigronervos. The distribution of BBTV in various tissues within the digestive system of P. nigronervos adults was observed through immunofluorescence detection and in situ hybridization, and the presence of BBTV in the honeydew of P. nigronervos and in Solenopsis invicta adults fed on this honeydew was detected by PCR.【Results】The expression of BBTV CP gene could be detected in P. nigronervos adults at 6 h after virus acquisition. Fluorescent labeling result indicated that BBTV was predominantly located in the anterior midgut (specifically in epithelial cells and circular muscles), accessory salivary glands, and excretory ostium of P. nigronervos adults. In situ hybridization result confirmed the presence of BBTV in the foregut, anterior midgut (epithelial cells), and principal salivary glands of P. nigronervos adults. PCR result revealed that the fragments of all six genetic components of BBTV could be detected in the honeydew secreted by viruliferous P. nigronervos as well as in S. invicta adults fed on this honeydew. 【Conclusion】A portion of BBTV acquired by P. nigronervos from banana bunchy top disease (BBTD) infected banana plants is transmitted in a persistent-nonpropagative circulative manner within the salivary glands, foregut, anterior midgut (epithelial cells and circular muscles), and excretory ostium of P. nigronervos adults. Conversely, another portion of BBTV is eliminated from the body of P. nigronervos in the form of honeydew. This study enhances our understanding of BBTV distribution in its transmission vector P. nigronervos and further confirms that BBTV spreads in its vector in a persistent-circulative manner. These findings are crucial for advancing research on the virus transmission mechanisms in P. nigronervos and for developing effective disease prevention and control strategies.

【Aim】 The ABC (ATP-binding cassette) transporters are important transmembrane proteins encoded by a supergene family. The expression of some ABC transporter genes significantly increase in some insecticide resistant strains of insect species. This study aims to clone the full cDNA of ABC transporter genes RhpaABCG9, RhpaABCG20 and RhpaABCG23 of the bird cherry-oat aphid, Rhopalosiphum padi, and to analyze their expression patterns in different developmental stages and different insecticide resistant strains. The results will provide a theoretical knowledge to clarify the biological functions of ABC transporters of R. padi, especially their roles in the resistance to insecticides of this insect. 【Methods】 RT-PCR and RACE were used to clone the full-length cDNAs of three ABC transporter genes from R. padi. The expression levels of the three genes in different developmental stages and different insecticide resistant strains of this aphid were detected by real-time quantitative PCR. 【Results】 The cDNAs of RhpaABCG9, RhpaABCG20 and RhpaABCG23 have an open reading frame (ORF) of 2 103, 2 436 and 2 082 bp with the deduced amino acid sequence of 700, 811 and 693 residues, respectively. Structural analysis showed that all the three proteins have the typical structural features of ABC transporter family. Phylogenetic analysis indicated that the amino acid sequences of these three proteins show high identity to those of the corresponding proteins from Acyrthosiphon pisum. Real-time quantitative PCR analysis showed that the three genes were expressed differently in different developmental stages. The expression level of RhpaABCG20 was not significantly different in various developmental stages. The expression level of RhpaABCG9 was the highest in the 4th instar nymphs and the lowest in the 1st instar nymphs. The expression level of RhpaABCG23 was significantly higher in the 3rd instar nymphs and significantly lower in the 1st instar nymphs than those in other instar nymphs, while there was no significant difference among the other instar nymphs. Compared with that in the susceptible strain, the expression level of RhpaABCG20 in the isoprocarb resistant strain of R. padi was significantly up-regulated, whilst the expression levels of RhpaABCG9 and RhpaABCG23 were insignificantly down-regulated. The expression levels of RhpaABCG20 and RhpaABCG23 in the imidacloprid resistant strain were significantly higher than in the susceptible strain, whilst the expression level of RhpaABCG9 was not significantly up-regulated in the resistant strain. 【Conclusions】 RhpaABCG9, RhpaABCG20 and RhpaABCG23 may play roles in the transport of insecticides in R. padi, and be related to the resistance of this pest to insecticides. The results provide a foundation for further study of the resistance mechanisms, and for the resistance management and integrated pest management of R. padi.

 【Aim】To screen cellulose-degrading bacterial strains from the gut of Allomyrina dichotomus for constructing composite bacterial consortia and to investigate their degradation capacity for spent mushroom substrate (SMS), thereby providing theoretical and practical foundations for SMS waste management.【Methods】Composite bacterial consortia were constructed based on non-antagonistic relationships among six cellulose-degrading bacteria with high enzyme activity (Bacillus velezensis M24, Bacillus subtilis H12, H11, H4 and M33, and Bacillus siamensis M32) isolated and purified from the larval gut of A. dichotomus. The activities of four cellulases (filter paper enzyme, endoglucanase, exoglucanase and β-glucosidase) were determined, the optimal composite bacterial consortia was selected according to its enzymatic activity profile, and the culture time, inoculation amount and incubation temperature for the selected composite bacterial consortia were optimized. The structural changes in the spent mushroom substrate before and after degradation were observed through scanning electron microscope by differential weight method.【Results】The composite bacterial consortia M24∶H11 was constructed based on the enzymatic activities of filter paper enzyme, endoglucanase, exoglucanase and β-glucosidase (18.08, 69.37, 19.09 and 17.95 U/mL, respectively). The optimal culture time, inoculation amount and culture temperature of M24∶H11 were 2 d, 1% and 40 ℃, respectively. Following optimization, the activities of the four cellulases increased significantly by 1.98-2.16-fold. At 25 ℃ within 30 d, M24∶H11 showed a significantly higher SMS degradation rate (up to 38.04%) than individual strains, with the degradation rate increasing over time. The degradation by M24∶H11 effectively disrupted the SMS surface structure, increasing its contact area.【Conclusion】The larval gut-derived composite bacterial consortia M24∶H11 of A. dichotomus was constructed and optimized for enzyme production, with high efficiency in SMS degradation. This study offers novel technical insights and theoretical support for the efficient control of the edible fungi waste.

Insects, the largest group of multicellular organisms on the Earth, are notable for their numerous species and varied morphology, generally harboring abundant microbes in their digestive tract. These microorganisms help the host in digestion, nutrition absorption, pheromone synthesis, as well as playing a role in the defense of harmful invaders, which strengthen the host immune activity. Lepidoptera is the second largest order in Insecta, with many common pest and beneficial insect species. Many methods and techniques have been developed for the research on the gut microbiota, which becomes a hot research topic in recent years. This review outlines the research of gut microbiota in lepidopteran insects ( e.g., Bombyx mori, Spodoptera littoralis and Plutella xylostella), including gut environment, microbial diversity and research methods. Furthermore, the community structure of several lepidopteran model insects and the roles of gut microbes in host’s detoxification and immune system are summarized. The findings we review here should be valuable for the further research on the gut microbiota in lepidopteran insects, and pave the way for developing novel strategies to control pests and protect beneficial insects.

【Aim】 This study aims to explore the effects of cucumber mosaic virus (CMV) infection on the aphid resistance of watermelon plants, with a focus on the roles of leaf epidermal resistance, mesophyll tissue resistance, and phloem resistance in regulating CMV-melon aphid (Aphis gossypii) interactions. 【Methods】 The differences in leaf epidermal resistance, such as the density of trichomes, wax content and stomatal number of the CMV-infected (CMV+) and CMV-non-infected (CMV-) watermelon plants were observed with microscope. The differences in the salicylic acid (SA) content, callose content, callose synthase activity and relative expression levels of phenylalanine ammonia-lyase gene ClPAL, pathogenesis-related protein gene ClPR, and callose synthase gene ClCalS7 in the leaves of CMV+ and CMV- watermelon plants were analyzed by high-performance liquid chromatography (HPLC), biochemical method, fluorescence spectrophotometry and real-time fluorescence quantitative PCR, respectively. Furthermore, the impact of CMV infection on the aphid fitness was determined by comparing the numbers of A. gossypii on the CMV+ and CMV- watermelon plants and analyzing their feeding behaviors via electrical penetration graph (EPG) in the laboratory. 【Results】 There were no significant differences in the leaf epidermal structural traits of CMV+ and CMV－ watermelon plants, including wax content in leaves, trichome number per mm² on the abaxial leaf surface and stomatal number per mm² on the abaxial leaf surface. However, CMV infection activated the SA pathway of watermelon plants, causing a 1.09-fold increase in SA content and a 4.77-fold up-regulation of the expression level of ClPR in watermelon leaves. CMV infection also increased the callose content in watermelon leaves by 2.51-fold and callose synthase activity by 3.07-fold, and significantly upregulated the expression level of ClCalS7 by 3.19-fold, respectively. Further experiments showed that CMV infection significantly reduced the number of A. gossypii by 46.14% and shortened the total duration of phloem feeding by 38.78%, while increased the number of potential drop (pd) waveform events by 54.30% and prolonged the total duration of saliva secretion by 31.48%. 【Conclusion】 Taken together, we speculated that CMV infection inhibited the feeding and population growth of A. gossypii by activating the SA signaling pathway and enhancing the callose deposition of watermelon plants, rather than altering the leaf epidermal structural traits. These findings revealed the key resistance pathways in regulating CMV-watermelon plant-melon aphid interactions, providing a scientific basis for understanding their co-evolutionary mechanisms and developing integrated management strategies against CMV and aphids.

 Mutualism between microorganisms and animals plays a crucial part in the adaptation and evolution of hosts. Phloem-feeding aphids engage in intimate symbiotic associations with a variety of symbionts. Many aphid species cause enormous damage to crops, fruit trees, forest trees and medicinal plants, and some of them are important worldwide quarantine pests. Studies on aphid symbionts will advance our knowledge of symbiotic relationships between organisms and provide theoretical guidance for green pest management. Almost all aphid species harbour the primary symbionts to supply nutrients such as essential amino acids and vitamin B lacking in their diets. Secondary symbionts are closely related to the ecological adaptation of aphids. In this review, we outlined the species, tissue localization, transmission modes, and functions of aphid symbionts, and systematically summarized the species composition of symbiont communities in different groups of Adelgidae, Phylloxeridae and Aphididae. To date, most studies on aphid symbiont diversity have focused on different biotic and abiotic factors influencing the symbiont community structure, including aphid species, biological characteristics, evolutionary history, host plants, geographical distribution, and environmental factors (e.g., temperature). In the future, research should undertake extensive surveys of symbiont diversity across a greater variety of aphid taxa, enhance attention to gut symbionts, explore the relative contributions of stochastic and deterministic processes in the assembly of aphid symbiont communities, identify core symbionts and their biological functions, and focus on the potential application of key symbionts in RNAi-based biopesticides, so as to facilitate the development of efficient and environmentally friendly aphid pest management strategies.

【Aim】This study aims to master the occurrence patterns of aphids in the wheat growing areas of northwestern Shandong, North China, explore their resistance levels to commonly used insecticides, and evaluate the field control efficacy of these insecticides against wheat aphids, so as to provide theoretical support for rational insecticide application and resistance management in wheat aphid control. 【Methods】The resistance levels of the wingless adults of Sitobion avenae and Rhopalosiphum padi to six commonly used chemical insecticides of four categories［lambda-cyhalothrin (pyrethroid), imidacloprid, thiamethoxam and acetamiprid (neonicotinoids), pymetrozine (pyridine), and emamectin benzoate (semi-synthetic antibiotic)］ were determined using the residual film method in glass tube. Concurrently, the population dynamics of wheat aphids in the field in northwestern Shandong were monitored from 2022 to 2024. The field control efficacy of the above six chemical insecticides and five biopesticides (Bacillus thuringiensis, rotenone, matrine, azadirachtin and veratrine) against wheat aphids was evaluated in May 2023. 【Results】 Bioassay results indicated that S. avenae exhibited moderate levels of resistance to acetamiprid and imidacloprid, and the median lethal concentraltion (LC₅₀) values of acetamiprid and imidacloprid against the wingless adults of S. avenae in 3 h were 2.800 and 3.871 μg/cm², respectively. R. padi showed decreased sensitivity to acetamiprid and pymetrozine, moderate level of resistance to lambda-cyhalothrin，and high level of resistance to imidacloprid, and the LC₅₀values of acetamiprid, pymetrozine, lambda-cyhalothrin and imidacloprid against the wingless adults of S. avenae in 3 h were 0.022, 0.593, 3.065 and 2.782 μg/cm², respectively. Both aphid species remained sensitive to the other tested insecticides. Field surveys revealed a parabolic trend in aphid occurrence in the wheat growing area of northwestern Shandong, with peak populations typically observed in mid-to-late May followed by decline in aphid number. Field efficacy trials demonstrated that biopesticides generally exhibited lower control efficacy against wheat aphids than chemical insecticides. Thiamethoxam, lambda-cyhalothrin, acetamiprid, B. thuringiensis and rotenone exhibited rapid action, achieving >75% control efficacy against wheat aphids at 3 d after application, significantly higher than the other six agents. Thiamethoxam, pymetrozine, lambda-cyhalothrin and acetamiprid showed sustained control efficacy against wheat aphids (>85% at 10 d after application). Azadirachtin had slower initial action but good persistence, reaching 84.14% control efficacy against wheat aphids at 10 d after application. 【Conclusion】 Based on the aphid occurrence patterns and resistance levels in the wheat growing area of northwestern Shandong, controlling aphid populations during wheat heading and flowering stages is recommended. Rotational application of pyrethroid, neonicotinoid and pyridine insecticides is advised for wheat aphid management. Given their slower initial action but prolonged efficacy, pyridine insecticides should be applied during the early outbreak stage of aphids.

【Aim】In recent years, extreme weather events have increased markedly in frequency in China and globally, with many regions experiencing substantially prolonged periods of elevated summer temperatures. During field surveys, we unexpectedly discovered a rare wild yellow morph of Acyrthosiphon pisum, but its biological characteristics remain uncharacterized. This study aims to investigate the ecological adaptability and survival risks of this novel color morph of A. pisum under intensified climate change, with the goal of providing a theoretical foundation for elucidating the evolutionary mechanisms of A. pisum and informing future population management and biological control strategies.【Methods】The competitive abilities of the wild yellow morph of A. pisum against those of the red and green morphs of A. pisum on three host plants (Vicia faba, Vicia sativa, and Medicago sativa) were first compared, and the starvation tolerance of apterous viviparous adults across all the three morphs of A. pisum under conditions of food deprivation were evaluated. The three color morphs of A. pisum were subsequently subjected to repeated high-temperature stress (35 ℃ for 2 h per day until adult stage) beginning at the 1st instar nymphal stage, and the changes in their population decline rates and fecundity were detected at the adult stage. Finally, the predation risk of the 3rd instar nymphs of each color morph of A. pisum by adult female Coccinella septempunctata was assessed, and the color differences (ΔE) between the body surfaces of the 3rd instar nymphs of various morphs of A.pisum and the leaves of V. faba leaves were analyzed.【Results】The yellow morph of A. pisum showed significantly lower competitive abilities than the red and green morphs of A. pisum on V. faba and M. sativa, but occasionally attained a competitive advantage over the red morph of A. pisum on V. sativa. Compared with the other color morphs of A. pisum, the yellow morph of A. pisum demonstrated greater starvation tolerance. After heat shock treatment (35 ℃ for 2 h per day), the numbers of aphids produced by the yellow morph of A. pisum in 6 d on its native host V. sativa and the high-nutrient host V. faba were 23.83 and 31.67 individuals, respectively, which represented relatively low values as compared with those of the other two morphs of A. pisum. Specifically, these values were lower than those observed in the green morph of A. pisum on V. sativa and the red morph of A. pisum on V. faba (28.67 and 41.67 individuals, respectively). In contrast to its disadvantage in fecundity, the yellow morph of A. pisum exhibited population decline rates of 32.78% and 26.11% on V. sativa and V. faba, respectively, after heat shock treatment, both of which were lower than those recorded for the red morph of A. pisum (67.22% and 38.89% on V. sativa and V. faba, respectively) and the green morph of A. pisum (44.43% and 42.22% on V. sativa and V. faba, respectively). The color difference (ΔE) between the body surfaces of the 3rd instar nymphs of the yellow morph of A. pisum and the leaves of V. faba was 52.26, significantly greater than those between the body surfaces of the 3rd instar nymphs of the red morph of A. pisum and the leaves of V. faba (37.69), and between the body surfaces of the 3rd instar nymphs of the green morph of A. pisum and the leaves of V. faba (17.76). The yellow morph of A. pisum was more vulnerable to predation by C. septempunctata adults, with the population decline rates exceeding 49.00%.【Conclusion】The yellow morph of A. pisum exhibits distinct ecological adaptation strategies. Although the yellow morph of A. pisum is disadvantaged in competition and more vulnerable to predation, its enhanced starvation tolerance and thermal resistance may provide a fitness advantage under increasingly frequent extreme weather events.

【Aim】 Brassica napus is one of the most important oilseed crops, and the average planting area is relative large in many provinces in China. Glucosinolate is the specific secondary metabolite in Brassicaceae plants. This study aims to ascertain whether the B. napus seeds with different glucosinolate and erucic acid contents affect the host location and propagation of pests on B. napus leaves. 【Methods】 Leaf-disc bioassay, cage experiment, and Y-tube olfactory test were used to analyze the host selection preference of Myzus persicae on six B. napus cultivars ［the high erucic acid-high glucosinolate cultivar ZY821 (control), and the low erucic acid-low glucosinolate cultivars (double-low cultivars) including ZS11, XN18, AGY558, AYK999 and MXY78］, and potted plant test was used to observe and determine the changes in individual number of M. presicae on plants of different B. napus cultivars. 【Results】There were no significant differences in the numbers of M. persicae adults and newborn nymphs on the six B. napus cultivars in cage experiment. In leaf-disc choice bioassay, more M. persicae adults fed on leaves of XN18 ［(25.50±2.21) individuals］ and ZS11 ［(24.70±1.57) individuals］, which were higher than the numbers of M. persicae adults on ZY821, AGY558, MXY78 and AYK999 leaves［(20.90±3.56), (14.80±1.78), (16.60±2.43) and (19.50±1.12) individuals, respectively］. In Y-tube olfactory test, M. persicae adults did not show host selection preference for six B. napus cultivars. In potted plant test, there was no significant difference in the total individual number of M. persicae after ten adults were released on plants of six B. napus cultivars on the 7th and 14th day. On the 21st day, the total individual numbers of M. persicae on plants of five double-low B. napus cultivars ZS11, XN18, AGY558, AYK999 and MXY78 (244.50±15.39, 235.67±50.60, 163.60±28.67, 237.40±16.57 and 237.20±12.35), respectively］ were higher than that in the control group［ZY821: (156.00±35.12)］, but the total individual number of M. persicae on ZS11 plants was significantly higher than that on ZY821 plants. 【Conclusion】 Double-low B. napus cultivars can affect the population dynamics of M. persicae at the seedling stage, but they have relatively limited effects on the host location behavior of M. persicae.

【Aim】 This study aims to sequence the complete mitochondrial genomes of representative species of Chaitophorinae, so as to analyze the mitochondrial genome architecture and explore the phylogenetic relationships of Chaitophorinae.【Methods】High-throughput sequencing of five species (Chaitophorus populeti, Chaitophorus populifolii, Chaetosiphella stipae, Periphyllus lyropictus and Sipha flava) from four genera within Chaitophorinae was performed using Illumina platform, mitochondrial genome assembly and annotation were then carried out. Comparative analyses were conducted along with previously reported Chaitophorinae mitochondrial genomes of six species (Periphyllus diacerivorus, Periphyllus koelreuteriae, Chaitophorus saliniger, Chaetosiphella stipae, Periphyllus acerihabitans and Laingia psammae) from four genera in NCBI. Phylogenetic trees were reconstructed for Chaitophorinae and its relatives based on 37 gene sequences of 27 complete mitochondrial genomes using maximum likelihood (ML) approach and Bayesian inference (BI). 【Results】 The mitochondrial genomes of Chaitophorinae are 15 787-17 770 bp in size, including 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes, a non-coding control region, and a non-coding repeat region. No gene rearrangement was observed. The nucleotide composition of the Chaitophorinae mitochondrial genomes displays a strong bias toward A+T. All PCGs initiate with standard ATN codons. cox1 and nad4 terminate with T--, except for cox1 in Periphyllus lyropictus, which terminates with TAA, and other PCGs use TAA or TAG as stop codons. atp8 has undergone positive selection and displays the fastest evolutionary rate, whereas cox1 exhibits the slowest evolutionary rate. Except for trnSAGN, which lost the dihydrouridine (DHU) arm, all tRNA genes can form the typical clover-leaf secondary structures. The control region located between rrnS and trnI varies in length from 606 to 1 710 bp, and some species of Chaitophorinae contain repeat sequences in this region. The repeat region situates between trnE and trnF, ranging from 544 to 1 876 bp in length and is composed of species-specific repeat units. The structural composition of the repeat sequences within the control region and the repeat region differs, and the sequence similarity of the repeat units within these two regions is low. Phylogenetic analyses supported the monophyly of Chaitophorinae and its two tribes, Siphini and Chaitophorini. Within Siphini, Sipha flava was placed at the most basal position of this clade. Within Chaitophorini, the monophyletic Chaitophorus and Periphyllus formed a sister group.【Conclusion】In this study, the complete mitochondrial genomes of representative species of Chaitophorinae were sequenced and analyzed. All examined species have the species-specific repeat region between trnE and trnF, which may be a common feature of the Chaitophorinae mitochondrial genomes. Mitochondrial genomes are effective in resolving the phylogenetic relationships within Chaitophorinae. Our study provides valuable molecular data resources for a better understanding of the characteristics of Chaitophorinae mitochondrial genomes, as well as the phylogenetic relationships and evolutionary history of this group.

【Aim】 Investigation of the action mechanisms of selective toxicity of type III sea anemone toxin (Av3) on insects would be highly valuable for future design of highly selective anti-insect compounds. 【Methods】 Reversed-phase high performance liquid chromatogram (RP-HPLC) and electrosprayionization mass spectrum (ESI-MS) were used to identify the purity and molecular weight of chemically synthesized Av3 wild type (Av3-WT) and its mutants. The toxicities of Av3-WT and its mutants to   Blattella germanica adults and their inhibition effect on the inactivation of sodium channel BgNav1-1a were tested by bioassay and double voltage clamp, respectively. Systematically replacing the extracellular loops of BgNav1-1a with those of rat sodium channel rNav1-2a was executed to determine the key region for Av3-WT selective toxicity by double voltage clamp. 【Results】 The toxicity of three Av3-WT mutants Y7A, W8A and Y18A generated via mutation of aromatic amino acids Y7, W8 and Y18 to B. germanica adults was significantly reduced, and the median knockdown dose (KD ₅₀) values of these three mutants increased by more than 10-fold compared with that of Av3 wild-type toxin (Av3-WT). As compared to the Av3-WT, the inhibition of the mutants Y7A, W8A and Y18A at the dose of 250 mmol/L on the inactivation of BgNav1-1a significantly decreased. The inhibition rates of Y7A, W8A and Y18A on channel inactivation were 12%, 23% and 8%, respectively, while that of Av3-WT was 62%. The chimera bearing DI/SS2-S6 of the rat sodium channel in BgNav1-1a almost lost sensitivity to Av3-WT, the inactivation of only 3.6% channels was inhibited. Substitution His404Y in DI/SS2-S6 completely abolished the inhibition effect of toxin on channel inactivation, and the inactivation of only 6% channels was inhibited by 1 μmol/L Av3-WT. 【Conclusion】 Three aromatic residues Tyr7, Trp8 and Tyr18 are involved in the constitution of bioactive surface of Av3-WT, DI/SS2-S6 is the key region affecting the specificity action of Av3-WT, and His404 in DI/SS2-S6 is critical for Av3-WT selective toxicity.

 Aphids, a group of widely distributed piercing-sucking insects, rely on the symbiotic relationship with the primary endosymbiont Buchnera to acquire essential nutrients for survival and reproduction. During the long-term coevolution, aphids have developed specialized bacteriocytes to mediate nutrient exchange with Buchnera while avoiding immune activation. This intracellular symbiosis is maintained through vertical transmission dependent on endocytosis and exocytosis mechanisms, ensuring persistent infection of Buchnera within aphid populations. However, the stable nutrient supply in endosymbiotic environment leads to extensive genome degeneration in Buchnera. On the one hand, the systematic loss of genes related to redundant nutrient metabolism and environmental stress response has resulted in the loss of over 90% of the genes of Buchnera genomes, leading to drastic genome reduction. On the other hand, the physical barrier formed by bacteriocytes prevents Buchnera from acquiring new genes from external bacteria, at the same time, the absence of key genes involved in DNA repair leads to the loss of mutation repair ability. These factors collectively result in extreme AT content and continuous functional gene loss in the genome of Buchnera. The genomic degeneration of Buchnera compromises its metabolic functions, manifesting as reduced essential amino acid synthesis, loss of key genes involved in inorganic salt metabolism, and dysregulation of heat shock protein expression. These deficiencies accelerate aphid speciation and reduce their adaptability under heat stress. To compensate for these obligate symbiotic constraints, aphids employ strategies such as acquiring secondary symbionts or replacing primary symbionts. Some lineages have even evolved dual primary symbionts, alleviating adverse effect of genomic degradation through functional complementation. In this review, we summarized the evolutionary paradox in aphid- Buchnera symbiosis. Although the degeneration of Buchnera genome improved the efficiency of nutrient supply, it restricted the adaptation of aphid hosts to the environmental changes. We further proposed novel compensatory strategies developed by aphids to overcome obligate symbiotic constraints, offering new perspectives for understanding relationship between insects and endosymbionts, and laying theoretical foundations for aphid control strategies targeting symbionts.

【Aim】 Bactrocera latifrons (Hendel) is one of the most important plant quarantine pests in plant production and trade, and it has wide host range and causes serious damage. Traditional identification methods are limited by such factors as raising period, feeding conditions and developmental stage, thus limiting the clearance rate of customs and quick identification of infestation situation of fruits. For this reason, a rapid identification technique for fruit fly species is desperately needed. 【Methods】 A pair of primers, FL680 and RL1057, was designed and synthesized based on the mtDNA COI sequence. For the PCR amplification and gel electrophoresis, B. latifrons (Hendel) was chosen as the positive control and other 20 species of fruit flies including B. correcta (Bezzi), B. dorsalis (Hendel) and B. cilifer (Hendel) were used as the negative controls. 【Results】 A clear and single 378 bp band was amplified only from B. latifrons, but not from the other 20 fruit flies. The SS-PCR identification method established in this experiment was applied and verified in inspection and quarantine, indicating that this method has high species specificity. 【Conclusion】 The rapid identification method developed here for B. latifrons can be applied in infestation monitoring and quarantine surveillance of fruit flies in ports.

【Aim】This study aims to explore the effects of exogenous juvenile hormone (JH) on the female ovarian development and transcription levels of the reproduction-key genes of Spodoptera frugiperda.【Methods】Polyclonal antibody was prepared after isolation and purification of vitelline protein of female S. frugiperda. The vitelline protein contents in the 7-8-day-old female pupae and 1-10-day-old female adults of S. frugiperda were determined using indirect enzyme-linked immunosorbent assay (ELISA). The 5-day-old female pupae were treated with 25 μg/individual precocene, and the newly emerged female adults were supplemented with 100 μg/individual exogenous JH analogue methoprene. Subsequently, the preoviposition period, oviposition period, number of eggs laid per female and hatching rate were calculated. The 3-day-old female adults were dissected to observe the ovarian development, measure the ovarian length, and take photographs. Finally, the expression levels of genes of vitellogenin (Vg) and vitellogenin receptor (VgR) in the 3-day-old female adults of each treatment were quantified using qPCR.【Results】The vitellin content of S. frugiperda increased first and then decreased as female adult emerged, reaching its peak in the fat bodies at 1-day-old and ovaries at 4-day-old. Precocene treatment resulted in a downregulation of the endogenous JH in S. frugiperda, leading to obvious impediment of ovarian development compared to the normally reared female adults as the blank control group. Additionally, there was a significant reduction in the amount of ovarian eggs. However, exogenous supplementation of methoprene after the precocene treatment effectively restored normal ovarian development. The average ovarian length in the precocene treatment group was 39.89 mm, which was significantly shorter than that in the blank control group of 49.79 mm. The average ovarian length in the methoprene treatment group was 46.67 mm, and significantly longer than that in the precocene treatment group, but had no significant difference from that in the blank control group. The average number of eggs laid per female in precocene treatment group significantly decreased to 576.33 grains, as compared to that in the blank control group (1 128.37 grains), significantly decreased by 48.91%. The average number of eggs laid per female in the methoprene treatment group was 806.93 grains, which was significantly higher than that in the precocene treatment group. The expression levels of SfVg and SfVgR in female adults treated with precocene were significantly downregulated as compared to those in the blank control group, while methoprene significantly promoted the expression levels of SfVg and SfVgR.【Conclusion】The suppression of endogenous JH through precocene treatment significantly impeded female fecundity, hindered normal ovarian development, and reduced the transcription levels of SfVg and SfVgR in female adults of S. frugiperda. Conversely, exogenous JH supplementation effectively restored the female fecundity. This study further validates the crucial regulatory role of JH in the reproductive process of S. frugiperda and provides a theoretical foundation for future research on the regulatory mechanism of JH of female reproduction.

【Aim】 The study aims to identify the genes of the chemosensory protein (CSP) family in Anopheles sinensis whole-genome， to predict the characteristics of these CSP genes， and to investigate the phylogenetics and evolution of the CSPs in representative dipteran species. 【Methods】 We searched， identified and named the CSP genes in An. sinensis， An. gambiae， Aedes aegypti and Culex quinquefasciatus genomes with Blast and HMM methods using CSP amino acid sequences downloaded from NCBI database as inquiry entry， analyzed the characteristics of the CSP genes in An. sinensis using bioinformatics methods， including the structure， location， splicing and Ka/Ks ratio of these genes， conservative domains and protein structures， and deduced the phylogeny of CSP genes using maximum likelihood (ML) method with MEGA software. 【Results】 The genomes of An. sinensis， An. gambiae， Ae. aegypti and Cx. quinquefasciatus contain 8， 8， 43 and 27 CSP genes， respectively. The CSP genes identified in An. sinensis (AsCSPs) are all supported by full-length transcripts， encoding 116 (AsCSP7) to 335 (AsCSP5) amino acids. Out of them， seven AsCSPs are located on Scaffold 51 and AsCSP8 on Scaffold116. AsCSP1-AsCSP8 possess 3， 2， 1， 1， 1， 2， 1 and 2 splicing variants， respectively， and AsCSP3 shows the highest expression level with a FPKM value of 385.46. All AsCSPs each has a N-terminal signal peptide consisting of 17-37 amino acids， and contains 4 conserved cysteine sites (CYS68， CYS75， CYS94 and CYS97)， which define two disulfide bonds (CYS68-CYS75 and CYS94-CYS97). Phylogenetic analysis results showed that eight CSP genes in four mosquito species are each grouped into a significant clade， and were named as CSP1-CSP8 group， respectively. Thirty-five and 18 CSP genes in Ae. aegypti and Cx. quinquefasciatus， respectively， are grouped into a special clade without homologous genes with Anopheles species, and was named as the Culicinae-specific group in this study. The Ka/Ks values of orthologous gene pairs between An. sinensis and An. gambiae were all less than 1， suggesting that the CSP gene family mainly experienced purifying selection during evolution. 【Conclusion】 The study provides an information frame of the CSP gene family in mosquito species， especially An. sinensis， and lays the foundation for further functional analysis of these genes.

【Aim】 This study aims to investigate the effects of the microbe Escherichia coli on the oviposition preference and survival rate of Drosophila melanogaster. 【Methods】 The 2-choice apparatus was used to examine the oviposition and position preference of wild-type D. melanogaster， and bacterial cells and supernatants were utilized to explore the reason for this behavior. D. melanogaster mutants of visual， gustatory and olfactory systems were applied to screen the corresponding sensing to E. coli，  and the survival rates of pupae and adults of D. melanogaster  were assessed to evaluate the potential effects of  E. coli on oviposition selection. 【Results】 The female adults of D. melanogaster dramatically avoided to lay eggs on the fly diet fermented by E. coli，  with an oviposition index of -0.89. The female adults avoided to oviposit on the supernatant of E. coli mixture， with an oviposition index of -0.52，  but did not avoid to oviposit on the bacterial cells， with an oviposition index of 0.02. The Orco2 mutant was deficient in oviposition repellency to E. coli-associated diet with an oviposition index of -0.25. E. coli decreased the survival rate of D. melanogaster progeny，  with less than 5% individuals surviving，  and the scarification on food surface rescued the survival rate of pupae and adults of D. melanogaster. 【Conclusion】 Female adults of D. melanogaster select the E. coli fermented food as the favored oviposition site. The oviposition preference of flies stems from the metabolites rather than E. coli cells. The olfactory system is required for D. melanogaster to distinguish the favored oviposition site. The oviposition repellence to E. coli consequently increases the survival and adaption of their offspring，  because E. coli forms the aquatic layer on food surface and deprives larvae of oxygen.

【Aim】 As one of the most important insects endohormones, ecdysone plays an important role in regulating the development and reproduction of insects. Five Halloween genes are involved in ecdysteroid biosynthesis and encode cytochrome P450 enzymes spook/CYP307A1, Phantom/CYP306A1, disembodied/CYP302A1, shadow/CYP315A1 and shade/CYP314A1, respectively. The brown planthopper, Nilaparvata lugens, is one of the most destructive pests of rice throughout Southeastern and Eastern Asia. For N. lugens, ecdysteroid regulated genes of RNAi technology management has gradually become a research hotspot. The objective of this study is to investigate the function of Halloween genes in N. lugens so as to provide the theoretical basis for the management of N. lugens and development of new pesticides. 【Methods】 Based on the genome and transcriptome database of N. lugens, five ecdysteroidogenesis-related Halloween genes in N. lugens were cloned using RT-PCR, and the deduced protein structure was predicted using different bioinformatics software, and the phylogenetic tree was constructed using the neighbor-joining method of MEGA 5.0. The expression profiles of these genes in different tissues of nymph and at different developmental stages of N. lugens were detected by quantitative real-time PCR. RNAi experiment was carried out to examine the effects of knockdown of Halloween genes on the development and reproduction of N. lugens. 【Results】 Five Halloween genes involved in ecdysteroidogenesis, i.e., NlCyp307a1, NlCyp306a1, NlCyp302a1, NlCyp315a1, and NlCyp314a1, were cloned and identified in N. lugens. Phylogenetic analysis revealed that the five Halloween genes belong to two superfamilies 2-Clan and Mito-Clan, respectively, and clustered with their homologous genes in other insects, suggesting that Halloween genes and edysteroidogenesis pathways are very highly conserved during insect evolution. NlCYP314A1 contains five conserved P450s motifs and two transmembrane domains, being a typical mitochondria cytochrome P450s. The results of qRT-PCR showed that five Halloween genes had higher mRNA abundance at 24 h and 60 h after molting in the 5th instar nymph stage. NlCyp314a1 was continually expressed during the whole developmental stage, and showed the highest expression level in adults. Among the examined tissues, thorax had the higher transcription level of NlCyp314a1 than head and abdomen, and fat body had the highest transcription level of NlCyp314a1, followed by leg, integument, wing bud, and midgut. Four days after injection of ds NlCyp314a1, the expression levels of NlCyp314a1 and NlFTZ-F1 in the treated individuals were extremely significantly decreased by 84.6% and 64.1%, respectively, compared with the control. NlCyp314a1 knockdown resulted in nymphs failed to molt on time, exhibited apparent phenotypic defects, and >95% mortality of the nymphs at day 7 after injection. NlCyp314a1 knockdown also resulted in the developmental abnormality of adult ovary. 【Conclusion】 Halloween genes of N. lugens involving in ecdysteroidogenesis are evolutionarily conserved. Silencing of selected Halloween gene expression causes phenotypic defects in molting and reproduction. These results suggest that Halloween genes encode functional proteins that are involved in molting and reproduction of N. lugens. Halloween genes might be used in altering genetically the progress of molting and reproduction of N. lugens. This study provides a theoretical basis for potential application of Halloween genes in the management of N. lugens.

The insect brain is composed of protocerebrum, deutocerebrum and tritocerebrum. The protocerebrum contains advanced sensory centers, such as mushroom body and central complex, controlling the advanced neural activities of insects, such as learning, memory and mobility. The deutocerebrum includes antennal lobe, which is the center of olfactory systems, while the tritocerebrum, which usually is not developed well, includes endocrine and mobile neurons. Unlike other organisms, the auditory and visual systems of insects are relatively degenerated because of their special biological characteristics. They prey, communicate and call mainly depending on the olfactory system, and thus their olfactory systems have been delicately developed. We here reviewed the research progress in the neuronal structure and function of insect brain (central complex, mushroom body and antennal lobe) and the genetic variation of the brain structures (sex dimorphism, differences between developmental stages, insects, and insects and other animals), and summarized the revealed mechanisms that insect brains process and identify odor signals.

 The emerging epidemics of obesity and diabetes have been recognized as major public health problems worldwide, and the primary etiology is an elevation of blood glucose and lipid levels resulting from an imbalance in energy availability and expenditure. Numerous reports have underscored that insects can be used as in vivo model organisms for human metabolic disorders, such as identification of evolutionarily conserved hormones (such as insulin-like peptide and adipokinetic hormone), signaling networks (such as target of rapamycin signaling pathway), and analogous organs or tissues (such as midgut and fat body) that regulate carbohydrate and lipid metabolism in arthropods and mammals. Here, we reviewed the regulatory mechanism of carbohydrate and lipid metabolism in insects, which involves the physiological function of the fat body and oenocytes, the antagonism between insulin-like peptide and adipokinetic hormone on hemolymph glucose regulation, the insulin and insulin-like growth factor signaling pathway (IIS) participated in nutrient metabolism and the cholesterol metabolism associated with steroid hormone synthesis, and also summarized the recent findings on Drosophila genes related with carbohydrate and lipid metabolism. This review will provide reference information for insect physiology and contribute to a better understanding of human metabolic disorders.  

【Aim】 To ascertain the resistance levels of the field populations of Rhopalosiphum padi from the Guanzhong Region of Shaanxi Province, nothwestern China to five pyrethroid insecticides and analyze the correlations between the mutation frequencies of the voltage-gated sodium channel (VGSC) gene (the target gene of pyrethroid) of various field populations and resistance levels. 【Methods】Nine field populations of R. padi were collected from the Guanzhong Region of Shaanxi Province during April-June in 2023 and 2024 and the susceptibility of the apterous adults to five pyrethroid insecticides (bifenthrin, permethrin, lambda-cyhalothrin, deltamethyrin and fenvalerate) was tested by leaf-dipping method. PCR was used to detect the types and frequencies of VGSC gene mutation of various field populations of R. padi. The correlation between the mutation frequency and the resistance level (resistance ratio, RR) was analyzed. 【Results】Bioassay results revealed that the apterous adults of various field populations of R. padi exhibited varying degrees of resistance to five pyrethroid insecticides. The apterous adults of the population collected from Xingping County, Xianyang City in 2023 (XP-2023) showed the highest resistance levels to type Ⅰ pyrethroid insecticides (bifenthrin and permethrin), with the RRs of 76.1 and 52.3, respectively. The apterous adults of the populations collected from Fufeng County, Baoji City in 2024 and 2023 (FF-2024 and FF-2023) and the population collected from Liquan County, Baoji City in 2023 (LQ-2023) showed the highest resistance levels to type Ⅱ pyrethroid insecticides (lambda-cyhalothrin, deltamethrin and fenvalerate), with the RRs of 60.7, 97.5 and 42.6, respectively. Detection of VGSC gene mutations revealed that, except for the populations collected from Wugong County, Xianyang City and Qishan County, Baoji City, respectively, in 2023 (WG-2023 and QS-2023), all the field populations carried heterozygous mutation (M918L) in the VGSC gene, with the mutation frequencies ranging from 5.0% to 47.5%. The mutation frequency of M918L was significantly correlated with the level of resistance to pyrethroid insecticides. 【Conclusion】The M918L heterozygous mutation in the VGSC gene is significantly correlated with the resistance levels of the field populations of R. padi to pyrethroid insecticides, indicating that this target mutation plays an important role in the resistance of the field populations of R. padi to these insecticides. It is recommended to minimize or avoid the use of pyrethroid insecticides in field control of R. padi and to continuously monitor the resistance levels of field populations.

【Aim】 This study aims to clarify the distribution pattern and feeding behaviors of Semiaphis heraclei on the adaxial and abaxial sides of Lonicera japonica leaves, and explore the control efficacy of spraying pesticides on the adaxial and abaxial sides of L. japonica leaves against S. heraclei, so as to provide a scientific basis for optimizing the control strategies of S. heraclei. 【Methods】 From April to May 2023, the occurrence amounts of S. heraclei on the adaxial and abaxial sides of L. japonica leaves at different leaf positions in the experimental field in Beijing were investigated every 5 d, the electrical penetration graph (EPG) technique was used to record the feeding behaviors of the 1-3-day-old adults of S. heraclei on the adaxial and abaxial sides of mature L. japonica leaves aged 30 d, and 0.027 mg/cm² imidacloprid and 0.020 mg/cm² pyrethrin were sprayed on the adaxial and abaxial sides of mature L. japonica leaves aged 30 d, respectively, and the mortality rates of the 1-3-day-old adults of S. heraclei on leaves were determined. 【Results】 S. heraclei adults were distributed on the adaxial side of L. japonica leaves at the first leaf position early and later shifted to the abaxial side. The abaxial sides of the middle part of almost all leaves consistently had significantly higher aphid numbers than the adaxial leaf sides throughout. A small number of aphids were found on individual leaves of basal leaf position, primarily on the abaxial leaf side. When S. heraclei adults fed on the abaxial leaf side of L. japonica, the probability of occurrence of aphid’s stylet salivation waveform in the phloem (E1 waveform) was significantly higher than that on the adaxial leaf side, being 2.00-fold as high as that on the adaxial leaf side, the total duration of E1 waveform was significantly longer than that on the adaxial leaf side, being 3.24-fold as long as that on the adaxial leaf side, and the probability of occurrence of phloem sap ingestion waveform (E2 waveform) was 2.25-fold as high as that on the adaxial leaf side. When S. heraclei adults fed on the xylem on the abaxial leaf side of L. japonica, the probability of occurrence of xylem sap ingestion waveform (G waveform) was significantly higher than that on the adaxial leaf side, being 1.29-fold as high as that on the adaxial leaf side, and the total duration of G waveform was significantly longer than that on the adaxial leaf side, being 2.00-fold as long as that on the adaxial leaf side, while the total duration of E2 waveform of S. heraclei adults fed on the adaxial and abaxial leaf sides exhibited no significant difference. The control efficacy of spraying 0.027 mg/cm² imidacloprid and 0.020 mg/cm² pyrethrin on the abaxial leaf side against S. heraclei adults was significantly higher than that on the adaxial leaf side, causing the corrected mortality rates of S. heraclei on the abaxial leaf side to be 2.00 and 1.79-fold as high as those on the adaxial leaf side, respectively. 【Conclusion】 S. heraclei adults are mainly distributed and cause damage on the abaxial side of L. japonica leaves, where it is more favorable for them to absorb water, and the control efficacy of spraying pesticides on the abaxial side of L. japonica leaves against S. heraclei adults is higher than that on the adaxial side.

【Aim】 This study aims to explore the physiological responses of silicon-treated rice plants to feeding stress by the white-backed planthopper, Sogatella furcifera, so as to provide a theoretical foundation for the rational use of silicon fertilizer in controlling S. furcifera. 【Methods】 The plants of the susceptible rice variety TN1 were treated with two silicon application levels ［grown in nutrient solution added with sodium silicate (Na₂SiO₃·9H₂O) at the concentration of 112 mg/L(Si+treatment group), and without addition of silicon (control group)］, then exposed to the feeding of the 3rd instar nymphs of S. furcifera. The contents of superoxide anion (O^-·₂), hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), the activities of antioxidant enzymes ［superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT)］ and defense enzymes ［phenylanlanine ammonialyase (PAL), polyphenol oxidase (PPO) and lipoxygenase (LOX)］, and lignin content in rice leaf sheaths were measured at 0, 12, 24, 48, 72 and 96 h after feeding on the rice plants in the Si+ treatment group or the control group. 【Results】 Compared to the control group, the Si+ treatment group exhibited significant reductions in O^-·₂ content by 7.8%-17.9% in rice leaf sheaths during 12-72 h after S. furcifera feeding, in H2O2 content by 15.5%-43.1% in rice leaf sheaths during 12-96 h (except at 24 h) after S. furcifera feeding, and in MDA content by 15.1%-35.3% in rice leaf sheaths during 24-96 h after S. furcifera feeding. During 12-96 h (except at 72 h) after S. furcifera feeding, the CAT and SOD activities in rice leaf sheaths in the Si+ treatment group were significantly increased by 25.8%-44.8% and 21.4%-47.6%, respectively, as compared to those in the control group. During 12-72 h (except at 24 h) after S. furcifera feeding, the POD activities in rice leaf sheaths in the Si+ treatment group significantly increased by 19.1%-54.5%, as compared to those in the control group. During 12-72 h after S. furcifera feeding, the PAL and PPO activities in rice leaf sheaths in the Si+ treatment group were significantly elevated by 17.6%-70.8% and 16.7%-38.3%, respectively, as compared to those in the control group. During 12-96 h after S. furcifera feeding, the LOX activities in rice leaf sheaths in the Si+ treatment group significantly increased by 9.9%-105.4%, as compared to those in the control group. During 12-96 h (except at 48 h) after S. furcifera feeding, the lignin contents in rice leaf sheaths in the Si+ treatment group significantly raised by 12.5%-59.3%, as compared to those in the control group. 【Conclusion】 Silicon application enhances rice resistance to S. furcifera by reducing reactive oxygen species and MDA contents, as well as by increasing the activities of antioxidant enzymes and defense enzymes, and the lignin content in rice leaf sheaths infested by S. furcifera.

【Aim】 Uridine diphosphate-glycosyltransferases (UGTs) are important detoxification enzymes in insects, playing important roles in various biological processes. In China, Rhopalosiphum padi has two main life history types: holocyclic i. e. cyclical parthenogenesis (CP) and anholocyclic i. e. obligate parthenogenesis (OP). In R. padi lineages with CP life history, the parthenogenetic individuals can switch from asexual reproduction to sexual reproduction, while the R. padi lineages with OP life history do not undergo reproduction switch and reproduce exclusively through parthenogenesis throughout the year. This study aims to explore the roles of UGTs in the reproduction switch of R. padi with CP life history using two UGT inhibitors (5-nitrouracil and sulfinpyrazone). 【Methods】 After injecting two UGT inhibitors (5-nitrouracil and sulfinpyrazone)(5×10^-10 mol/individual) into wingless adults from the lineage of R. padi with CP life history, the changes in UGT contents in the aphids were measured, and the numbers of virginoparae, gynoparae and males produced by cyclical parthenogenetic R. padi adults, and the start time, end time and total time of producing virginoparae, gynoparae and males were observed and analyzed. 【Results】 The UGT contents in the wingless adults of R. padi injected with 5-nitrouracil and sulfinpyrazone were significantly lower than those in their corresponding controls (injected with ddH₂O and acetone, respectively), reduced by 35.06 and 33.98 ng/L, respectively. The individual numbers of virginoparae and gynoparae in the offspring significantly decreased by 21.00 and 20.00, when the wingless adults of R. padi were injected with 5-nitrouracil, while the individual numbers of virginoparae and males in the offspring significantly decreased by 16.10 and 6.70, when the wingless adults of R. padi were injected with sulfinpyrazone. Both inhibitors significantly delayed the start time of producing gynoparae by 1.30 d, compared to the control. Injection of 5-nitrouracil had no significant effect on the start time of producing males, while injection of sulfinpyrazone significantly delayed the start time of producing males by 2.10 d, compared to their corresponding controls. Injection of 5-nitrouracil and sulfinpyrazone both significantly advanced the end time of producing virginoparae by 2.10 and 3.20 d, respectively, and significantly delayed the end time of producing gynoparae, compared to their corresponding controls. Both UGT inhibitors significantly shortened the total time of producing virginoparae but had no significant effect on the total time of producing males, compared to their corresponding controls. Injection of 5-nitrouracil did not significantly affect the total time of producing gynoparae, whereas injection of sulfinpyrazone significantly prolonged the total time of producing gynoparae, compared to their corresponding controls. 【Conclusion】 UGTs may play an important role in the reproduction switch of R. padi with holocyclic life history.

Heavy metal pollution has become a global environmental problem and severely threatened the biological diversity and people's health. More and more attention has been paid to the potential effects of heavy metal pollution on insects as one of the important groups of global biological diversity. The accumulation of heavy metals in insects may influence their development. It has been demonstrated that insects could be contaminated by respiration, ion absorbing through integument and food intake. Excessive metal accumulation in insects could not only cause cell ultrastructure variations and genetic homeostasis alteration, but also induce cell apoptosis and influence cell viability and proliferation. But, heavy metals can be stored in insect organs with digestive, storage or excretory function in form of “granules”, and be transported into lysosomes to detoxify. Moreover, metallothionein and antioxidant enzymes also play important roles in the process of detoxification.

【Aim】 Bactrocera is the most economically significant genus of tephritid flies. The present study aimed to make molecular identification and phylogeny analysis of common species of the genus Bactrocera. 【Methods】 Twenty-one species belonging to eight subgenera of the genus Bactrocera that were frequently intercepted from customs were identified using DNA barcoding technology based on mitochondrial cytochrome c coxidase subunit I (COI) gene. The partial fragments (about 650 bp) of the mtDNA COI gene were amplified using DNA barcoding universal primers. The obtained COI gene fragments were sequenced and aligned. The phylogenetic tree was established by a neighbor-joining (NJ) method. The intra-and inter-species genetic distances were calculated with MEGA version 5.0 software using the Kimura 2-parameter model. 【Results】 The identification results based on the phylogenetic tree were consistent with those based on morphological analyses for the 21 fruit fly species. In these species, 11 species of Bactrocera formed monophylies of themselves, the other 10 species shared one monophyly， and all bootstrap values of the original divergence among different haplotypes within the same species were over 99%. The average inter-species genetic distance between the 21 species was 35.8 times higher than the average intraspecies genetic distance of the 10 species (0.1540 vs. 0.0043). There was no overlap between intra- and inter-species genetic distances. 【Conclusion】 The results indicated that the DNA barcoding based on the partial sequence of mtDNA COI gene cauld provide rapid and accurate identification of Bactrocera species. The technology could be used in identifying and monitoring tephritid fruit fly species.

【Aim】 To identify genes of the CYP6Y subfamily in Anopheles sinensis, analyze their structure and characteristics, and deduce their possible functions. 【Method】 The CYP6Ys cDNA transcripts were retrieved and identified by two ways of Blasts using An. gambiae CYP6Y1 as query sequence against the transcriptome data of An. sinensis. The structure, characteristics and possible functions of the CYP6Y genes identified were analyzed using bioinformatics methods. 【Results】 Two genes of the CYP6Y subfamily were identified from An. sinensis transcriptome sequencing data, and named as AsCYP6Y1 (GenBank accession number: KF709397) and AsCYP6Y2 (GenBank accession number: KF709398) , respectively. Sequence analysis showed that AsCYP6Y1 and AsCYP6Y2 are 1 713 bp and 1 815 bp in length, encoding 502 and 526 amino acids, respectively. Gene structure analysis showed that the genes of this subfamily only contain one phase “1” intron and form a conserved synteny with other P450 genes. Protein structure prediction showed that the encoded proteins of these two genes contain five P450 characteristic sequences and six specific substrate binding sites, but have no signal peptide sequence, and are localized in cytoplasm. The 3D structural prediction showed that AsCYP6Y1 has 18 α-helix and 13 anti-parallel β-strands, while AsCYP6Y2 has 19 αhelix and 11 antiparallel βstrands. Two CYP6Y genes were also identified in An. darlingi using the same method. Phylogenetic analysis showed that AsCYP6Y1 and AsCYP6Y2 are grouped with CYP6Y1 and CYP6Y2 of other Anopheles species, respectively, with the bootstrap values greater than 90%. The Ka/Ks ratio analysis showed that the Ka/Ks ratio of AsCYP6Y1 and AsCYP6Y2 compared with CYP6Y1 and CYP6Y2 of other Anopheles species were all less than 1. The relative evolutionary rate test showed that the rates of subfamilies CYP6Y and CYP6M were significantly higher than those of the subfamily CYP6P in An. sinensis, while no significant difference between subfamilies CYP6Y and CYP6M was observed. 【Conclusion】 Two genes of the CYP6Y subfamily have been identified and characterized in An. sinensis and An. darlingi, which had earlier been found in two other Anopheles species ( An. gambiae and An. funestus), suggesting the wide and specific existence of the genes of the CYP6Y subfamily in Anopheles.
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 【Aim】 To evaluate the attractiveness of three plant volatile compounds linalool, methyl jasmonate and geraniol to Thrips hawaiiensis and Orius strigicollis, so as to provide a basis for utilizing plant volatile compounds to attract O. strigicollis for controlling T. hawaiiensis in the field. 【Methods】 The attraction rates of linalool, methyl jasmonate and geraniol at the concentrations of 980, 10, 0.1 and 0.001 g/L to T. hawaiiensis adults, and the 5th instar nymphs and adults of O. strigicollis were tested, and the time effect of attraction and attraction rates of 980, 10 and 0.1 g/L geraniol to adults of T. hawaiiensis and O. strigicollis were determined using a Y-type olfactometer. The numbers of T. hawaiiensis and O. strigicollis adults attracted by 10 g/L geraniol were further determined in the field greenhouse condition. 【Results】 The attraction rates of methyl jasmonate at various test concentrations to T. hawaiiensis adults and the 5th instar nymphs of O. strigicollis were not significantly different from those of the control group (paraffin oil). Linalool at the concentration of 980 g/L showed significantly enhanced attraction rate to T. hawaiiensis adults but linalool at various test concentrations exhibited no significant change in the attraction rate to the 5th instar nymphs and adults of O. strigicollis compared with the control group. The attraction rate of pure geraniol (980 g/L) to T. hawaiiensis adults significantly increased, and those of high concentrations (10 and 0.1 g/L) of geraniol to O. strigicollis adults significantly increased but those of 10 and 0.1 g/L geraniol to O. strigicollis nymphs did not change significantly as compared with those in the control group. Geraniol at different concentrations had a significant time effect on the number of T. hawaiiensis and O. strigicollis adults attracted, and the number of adults attracted by 980 and 10 g/L geraniol were significantly higher than those attracted by geraniol at the other concentrations at 2 h after treatment. Regardless of whether the pepper seedlings were damaged by T. hawaiiensis adults or not, those treated with 980 and 10 g/L geraniol had significantly higher attraction rates to adults of O. strigicollis compared with the control (clean water). Treatment group spraying 10 g/L geraniol in the field greenhouses had no significant difference in the number of attracted adults of T. hawaiiensi in 5 h but had significantly increased number of attracted adults of O. strigicollis compared with the control group spraying clear water. 【Conclusion】 Three plant volatile compounds linalool, methyl jasmonate and geraniol have different attraction rates to T. hawaiiensis and O. strigicollis. Geraniol at the concentration of 10 g/L can effectively attract adult O. strigicollis within 5 h but can not significantly attract T. hawaiiensis. These results provide the theoretical basis and technical support for using geraniol to attract O. strigicollis for controlling T. hawaiiensis.

Rearing of Anomala corpulenta Motschulsky were conducted in the laboratory condition and the main influencing factors were evaluted. The results showed that it took 274.3 days for the beetle to complete a life cycle in the laboratory conditions. The duration of the 3rd instar reared in the laboratory was 101.8 days shorter than that in fields. The growth of larvae was influenced by such factors as soil humidity, food and pathogens. The average survival rate of eggs was 86.0% while those of the 1st instar, 2nd instar and 3rd instar larvae were 82 . 0%, 76.0% and 60.0%, respectively. The mortalities of the 10 day-old and 15 day-old larvae reared in the soil with potato as food for 14 days were 8.8 ％± 1.6% and 4.0 ％± 1.6% respectively, significantly lower than those for the newly hatched larvae and 5 day-old larvae. This result suggested that the larval age of 10 － 15 day-old was the optimum stage for bioassay of Bt. The larvae grew normally in the UV-irradiated loam and sandy loam soil, with their mortalities lower than that in the untreated and sterilized loam and sandy loam soil.

【Aim】 This study aims to explore the sublethal effects of cyantraniliprole on Spodoptera exigua (Hübner)so as to provide a scientific basis for the integrated management program for S. exigua and the rational use of cyantraniliprole. 【Methods】 The toxicity of cyantraniliprole on the 3rd instar larvae of S. exigua was assayed with diet-incorporation bioassays, and the effects of cyantraniliprole at two sublethal doses (LC ₁₀ and LC ₂₅) on the growth and development of S. exigua and the activities of three detoxifying enzymes were assayed. 【Results】 When the S. exigua larvae were treated with two sublethal doses of cyantraniliprole (LC ₁₀ and LC ₂₅), their growth was significantly restrained compared to that in the control group, the average body weight was inhibited by 11.55% and 27.68% and the developmental durations from the 3rd instar larva to pupa were elongated by 0.07 and 0.20 d, respectively. The pupation rates in the LC ₁₀ and LC ₂₅ treatment groups were 63.89% and 49.43% and were significantly lower than that of the control (80.93%). The adult longevity in the LC ₁₀ and LC ₂₅ treatment groups was obviously shortened by 1.11 d and 2.08 d, respectively, and the number of eggs laid per female and the egg hatching rates in the two treatment groups were significantly lower than those of the control. The activities of carboxylesterase (CarE) and glutathione- S-transferases (GSTs) in the 3rd instar larvae treated with the two sublethal doses of cyantraniliprole were promoted first and then decreased from 24 h to 96 h aftertreatment. The activities of mixed function oxidase (MFO) were also inhibited at 48 h and 72 h after treatment, and the inhibition effect was in proportion to the cyantraniliprole dose. 【Conclusion】 These results demonstrate that sublethal dose of cyantraniliprole can significantly restrain the growth and development of S. exigua and the activities of three detoxifying enzymes in its larvae.

【Aim】 The camellia weevil,  Curculio chinensis Chevrolat, is an important pest attacking fruits of the oil tea  Camellia, an endemic genus to China, and causes tremendous fruit drop of its host plants. To reveal the oviposition strategy of  C. chinensis, we explored the relationships between oviposition activity of C.chinensis  and the traits of its host fruit. 【Methods】 During the most active oviposition season, 960 fruits of  C. meiocarpa  were collected randomly from an oil tea ( Camellia meiocarpa) farm. The number of punctures and clutch size of C. chinensis, as well as the weight, length and diameter of each fruit were measured, and the difference of fruit size among oviposition-punctured fruits, feeding-punctured fruits and non-damaged fruits was analyzed through one-way ANOVA (LSD), and the effect of fruit traits on feeding and oviposition activity was analyzed through linear regression model. A choice test of the pest on fruits size was carried out, and the difference of fruit size between selected and non-selected fruits was analyzed by paired-samples t test. 【Results】 Oviposition-punctured fruits of C. meiocarpa were significantly larger than feeding-punctured fruits, while the latters were significantly larger than non-damaged fruits in terms of weight, length, diameter, and volume ( P＜0.01). The number of punctures, clutch size and weevil parasitism rate were positively correlated with fruit size ( P＜0.01), suggesting that parental weevils prefer larger fruits to feed and oviposite. The female adults of C. chinensis showed obvious preference to larger fruits when the difference of fruit size between the two fruits tested was significant, and heavily damaged fruits were significantly larger than lightly damaged fruits in terms of length and diameter after infection by female adults of C. chinensis for 12 h. Independent of host fruit traits, C. chinensis laid one egg in each puncture hole. 【Conclusion】 C. chinensis adults prefer larger fruits to feed, which supports the optimal foraging theory. C. chinensis adults also prefer larger fruits to oviposite. The small clutch size would reduce intraspecific competition C. chinensis between offsprings and increase the probability of larval development, and thus they would be more likely to successfully exit from host fruits. We infer that the single egg laying behavior in C. chinensis is a riskspreading strategy, an adaptation toward limited food resource.