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  • Monthly, Founded in 1950
    Supervisor:Chinese Academy of Sciences
    Sponsor:Institute of Zoology,Chinese Academy of Sciences
    The Entomological Society of China
    Domestic postal code: 2-153
    Foreign issuance code: Q61
    ISSN 0454-6296
    CN 11-1832/Q
Table of Content
20 February 2022, Volume 65 Issue 2
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  • RESEARCH PAPERS
    DNA methylation affects wing development of Bombyx mori through regulating autophagy
    GONG Cheng-Cheng, LÜ Hao, ZHENG Si-Chun, XU Guan-Feng
    2022, 65(2):  119-129.  doi:10.16380/j.kcxb.2022.02.001
    Abstract ( 448 )   PDF (12458KB) ( 243 )   PDF（mobile） (12458KB) ( 191 )   　　
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    【Aim】This study aims to investigate whether DNA methylation affects wing development of Bombyx mori through regulating autophagy. 【Methods】B. mori ovarian Bm12 cells and B. mori prepupae were treated with 5azadC, a DNA methylation inhibitor, at the doses of 1 and 2 μg, respectively, the number of Bm12 cells was observed under fluorescence microscopy, the methylation level in Bm12 cells was detected by dot blotting, the autophagy intensity was detected by lysosome staining, the expression levels of autophagyrelated protein (Atg) genes were detected by RT-qPCR, and the typing of the autophagy marker LC3 protein in Bm12 cells was detected by Western blotting and immunohistochemistry. Meanwhile, the wing phenotype of adult was observed, and the abnormal wing rate and wing area were calculated. After B. mori prepupae were treated with the autophagy activator SMER28 (2 μg), and using autophagy inhibitor Spautin-1 (2 μg) to rescue 5-aza-dC-treated prepupae, the autophagy intensity in the wing cells was detected by lysosome staining, the wing phenotype was observed, and the abnormal wing rate and wing area were calculated. 【Results】Treatment with 1 μg of 5-aza-dC inhibited the growth and decreased the methylation level of Bm12 cells, increased the autophagy level in Bm12 cells at 12, 24 and 48 h after treatment, and up-regulated the expression of Atg genes in Bm12 cells at 48 h after treatment. Injection of 2 μg of 5-aza-dC into B. mori prepupae increased the autophagy level, up-regulated the expression of Atg genes in adult wing cells, and resulted in a large proportion of deformed wings at 24, 48 and 72 h after treatment, with the increased abnormal wing rate (increased by 72.62%) and the decreased wing area (decreased by 66%) of adult. Injection of 2 μg of SMER28 into B. mori prepupae increased the autophagy level in the adult wing cells and resulted in a large proportion of deformed wings at 24, 48 and 72 h after treatment, with the increased abnormal wing rate (increased by 75.13%) and the decreased wing area (decreased by 48.79%) of adult. In addition, rescue experiment using Spautin-1 to rescue the 5-aza-dC-treated prepupae revealed that the autophagy inhibition could alleviate the effect of DNA demethylation on the adult wing development. 【Conclusion】The results of this study demonstrate that DNA methylation plays a role in the wing development of B. mori by regulating autophagy. Our results provide the experimental evidence for the regulation of DNA methylation on the insect development.
    Reasons for changes of hemocyte densities and the relationship between hemocyte density and high temperature resistance of Bombyx mori larvae
    LI Tian, LIU Hao-Yu, WANG Ge-Min, LI Ya-Teng, YU Hua-Xian, YAN Dong-Sheng, GUO Yu, ZHANG Tai-Yun, CHEN Ping
    2022, 65(2):  130-143.  doi:10.16380/j.kcxb.2022.02.002
    Abstract ( 380 )   PDF (4261KB) ( 150 )   PDF（mobile） (4261KB) ( 15 )   　　
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    【Aim】Hemocyte plays a leading role in insect hemolymph immunity. Analyzing the changes of hemocyte density of the silkworm, Bombyx mori larvae and their causes, and the relationship between hemocyte density and B. mori resistance, is an important part of hemocyte immune regulation and resistance breeding of silkworm.【Methods】Hemocyte density (hemocyte number) in 10 μL hemolymph of the silkworm variety Dazao at different instars (the day-1-4 4th instar, the day-1-8 5th instar and the wandering larval stage) was evaluated by a hemocytometer. The cross-sectional image area was estimated by ImageJ software to represent the relative size of hematopoietic organs. The numbers of hemocytes in the hemolymph of the day-1 5th instar larvae of different silkworm varieties including Jingsong, Haoyue, Liangguang 2, 932, Furong, 7532 and Xianghui were measured by a hemocytometer. The relative expression levels of hematopoietic regulation factor genes BmBCFI, BmUsh, BmGATA and BmLz in the hemolymph of the day-1 5th instar larvae of Haoyue and Liangguang 2 were detected by qRT-PCR. After the day-1 and -3 5th instar larvae of Dazao were infected by Escherichia coli for different time, the hemocyte numbers in the hemolymph were measured by a hemocytometer and the relative expression levels of the above hematopoietic regulation factor genes in the hemolymph were detected by qRT-PCR. After RNAi of BmBCFI, BmUsh and BmLz for different time, the relative expression levels of target genes in the hemolymph of the 5th instar larvae of Dazao were detected by qRT-PCR. At 6 h after the 5th instar larvae of Dazao were infected by E. coli following RNAi of BmBCFI, BmUsh and BmLz for 48 h, the relative expression levels of target genes and immune-related genes BmRelish, BmCactus, BmSpzl and BmPGRP-LE in the hemolymph were detected by qRT-PCR, and the numbers of different types of hemocytes in the hemolymph were counted by a hemocytometer. The correlations between the hemocyte number and viability of the 5th instar larvae at high temperature of 35℃ were analyzed for 12 practical silkworm varieties.【Results】The hemocyte numbers of Dazao gradually increased during the 4th instar larval stage, reached a peak at the day-1 5th instar larval stage, began to decrease at the day-2 5th instar larval stage, and then slightly increased during the wandering stage. The hematopoietic organs gradually grew during the early and middle 5th instar larval stages, reached a peak at the day-6 5th instar larval stage, then diminished significantly and finally disintegrated. The time and trend of changes in the size of hematopoietic organs were not consistent with those of the changes of the hemocyte numbers. The expression levels of hematopoietic regulation factor genes BmBCFI, BmUsh and BmLz in Liangguang 2 with higher hemocyte numbers were higher than those in Haoyue with lower hemocyte numbers. After the 5th instar larvae of Dazao were infected by E. coli, the expression levels of BmBCFI, BmUsh and BmLz were significantly up-regulated when hemocyte numbers reached a peak. The oenocytoid numbers significantly reduced after down-regulating BmLz or BmUsh via E. coli infection following RNAi, and the plasmatocyte number and the number of total hemocytes significantly decreased after down-regulating BmBCFI via E. coli infection following RNAi. The expression levels of BmRelish in the Imd pathway and BmCactus in the Toll pathway were both significantly down-regulated after down-regulating BmBCFI or BmUsh via E. coli infection following RNAi, implying that BmBCFI and BmUsh are related to the activation of NF-κB signaling pathway and the formation of immune factors such as antimicrobial peptides. The hemocyte numbers varied greatly among different silkworm varieties, and the summer-autumn varieties tended to have higher hemocyte numbers than spring varieties. There was a negative correlation between the hemocyte number and the death index of the 5th instar larvae of silkworm reared at high temperature of 35℃.【Conclusion】Expression level of hematopoietic regulation factor genes of B. mori can affect the hemocyte density. BmUsh and BmLz influence the oenocytoid density of B. mori, and BmBCFI is associated with the plasmatocyte formation. Moreover, BmBCFI and BmUsh are likely to be related to the activation of NF-κB signaling pathway in B. mori. The hemocyte density is positively correlated with the viability of B. mori larvae fed at high temperature.
    Morphology and ultrastructure of the alimentary canal of Megalurothrips usitatus (Thysanoptera: Thripidae)
    WANG Liang, LIU Yu-Yan, LI Heng, CHEN Yi-Xin, LIN Shuo, YU Yun, TIAN Hou-Jun, LIN Tao, ZHANG Jie, CHEN Yong, WEI Hui
    2022, 65(2):  144-156.  doi:10.16380/j.kcxb.2022.02.003
    Abstract ( 161 )   PDF (28876KB) ( 216 )   PDF（mobile） (28876KB) ( 34 )   　　
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    【Aim】The aim of this study is to explicit the morphology and ultrastructure of the alimentary canal of the bean flower thrips, Megalurothrips usitatus at different developmental stages. 【Methods】 Confocal laser scanning microscope (CLSM) and transmission electron microscope (TEM) were used to observe the morphology and ultrastructure of the alimentary canal of nymphs, pre-pupae, pupae and adults of M. usitatus. 【Results】The alimentary canal of M. usitatus is composed of foregut, midgut, hindgut and Malpighian tubules. The mean length of the alimentary canal of the 1st instar nymphs, 2nd instar nymphs, pre-pupae, pupae, female adults and male adults are 1 642.65±158.68, 2 233.68±133.76, 1 264.39±92.43, 1 169.81±59.48, 2 380.32±196.67 and 1 344.31±143.29 μm, respectively. The foregut includes the pharynx, esophagus, crop and cardia.The intestinal wall is composed of the outer layer of myoepithelial cells, muscle layer, epithelial cell layer and cuticle from the outside to the inside. A large number of vesicles and inconspicuous cuticle were observed in the foregut of the 1st and 2nd instar nymphs. The cuticle of foregut cells in the prepupae, pupae and adults is thicker, and the muscles are also relatively developed. The midgut is divided into three parts, namely anterior, middle and posterior parts. The muscle cell layer and epithelial cell layer are distributed from the outside to the inside, and the side near the midgut lumen is specially formed into the microvilli structures.There are reserve materials in the anterior midgut cells of the 1st instar nymphs. Myelin-like structures and more autophagosome-like vesicle structures were observed in the anterior midgut cells of the 2nd instar nymphs. The concentric spherocrystal structures are widespread in the midgut cells of pre-pupae and pupae,and the basal labyrinth is obvious in the cells of the anterior and middle midgut of adults. The hindgut is composed of ileum and rectum, and has developed muscle layer and cuticle at each developmental stage. There is no muscle layer in the Malpighian tubules, but organelles or structures such as mitochondria, rough endoplasmic reticulum, basal labyrinth and zonulae adherens still exist in epithelial cells. No basal labyrinth structure was observed at the base of Malpighian tubules of pre-pupae and pupae, but multivesicular bodies are distributed in the pre-pupal Malpighian tubule cells. In addition, spherocrystal was observed in the cytoplasm of the pupal Malpighian tubules.【Conclusion】There are obvious differences in the morphological structure of the alimentary canal of M. usitatus at different developmental stages. In this study, according to the morphological composition, the functions of different parts of the alimentary canal were speculated as well. The results will provide experimental basis for further analysis of the morphology and functional differentiation of the alimentary canal of thrips.
    Cloning of trehalase genes in Calliptamus italicus (Orthoptera: Acrididae) and their expression patterns in eggs under cold acclimation
    LIU Qian, LUO Di, Roman JASHENKO, JI Rong
    2022, 65(2):  157-166.  doi:10.16380/j.kcxb.2022.02.004
    Abstract ( 75 )   PDF (4789KB) ( 90 )   PDF（mobile） (4789KB) ( 11 )   　　
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    【Aim】This study aims to clarify the role of trehalase genes in the resistance to low temperature stress in Calliptamus italicus eggs by cloning trehalase genes in C. italicus eggs, and analyzing their expression profiles in eggs at different developmental stages and the expression changes after cold acclimation. 【Methods】The full-length ORF sequences of trehalase genes from C. italicus eggs were amplified by RT-PCR, and analyzed by bioinformatics tools. RT-qPCR was used to detect the expression changes of trehalase genes in C. italicus eggs at the early stage, diapause stage and diapause termination stage under the room temperature (27℃) and after acclimation to low temperature (0℃) for 15 d. 【Results】Four trehalase genes from C. italicus eggs were cloned and named CiTreM1, CiTreM2, CiTreS1 and CiTreS2, with the GenBank accession numbers of MZ669810, MZ669811, MZ669812 and MZ669813, respectively. Among their encoded proteins, CiTreM1 and CiTreM2 are membrane-bound trehalases, and CiTreS1 and CiTreS2 are soluble trehalases. CiTre genes were expressed in C. italicus eggs at various developmental stages. At the room temperature (27℃), CiTreS1 and CiTreS2 had the highest expression level in C. italicus eggs at the early stage, while CiTreM2 and CiTreM1 had the highest expression level in eggs at the diapause stage and diapause termination stage, respectively. After acclimation to low temperature (0℃) for 15 d， the expression levels of CiTreM1 and CiTreM2 increased in eggs at all the three stages, while those of CiTreS1 and CiTreS2 decreased only in eggs at the early stage but increased in eggs at the other stages. After cold acclimation, the expression levels of CiTreM1 and CiTreM2 increased the most in C. italicus eggs at the early stage, while those of CiTreS1 and CiTreS2 increased the most in eggs at the diapause termination stage. After acclimation to low temperature (0℃) for 15 d, the expression levels of the four CiTre genes were obviously different in C. italicus eggs at the same stage, and CiTreM2 showed the highest expression level in C. italicus eggs at early stage and the diapause stage, and CiTreS1 showed the highest expression level in eggs at the diapause termination stage. 【Conclusion】The four cloned trehalase genes in C. italicus eggs are all involved in the development of C. italicus eggs. According to the changes in expression level before and after cold acclimation, CiTreM2 and CiTreS1 play a key role in the process of C. italicus eggs resisting low temperature stress.
    Analysis of differentially expressed genes in testes and ovaries of Apis cerana cerana (Hymenoptera: Apidae)
    CHENG Fu-Ping, YUAN Fang, XI Fang-Gui, QIN Kai-Xin, HU Xiao-Fen, WANG Zi-Long
    2022, 65(2):  167-175.  doi:10.16380/j.kcxb.2022.02.005
    Abstract ( 360 )   PDF (5544KB) ( 169 )   PDF（mobile） (5544KB) ( 16 )   　　
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    【Aim】In honeybee colonies, both drones and queens have fully developed gonads, but they do not reach sexual maturity at the same time. The aim of this study is to explore the gene expression difference of gonads between drones and queens of the Asian honey bee, Apis cerana cerana. 【Methods】Illumina sequencing technology was used to analyze the differentially expressed genes (DEGs) in the transcriptome between testis of drone and ovary of queen of A. cerana cerana. 【Results】We identified 5 312 DEGs between testis and ovary of A. cerana cerana, among which 2 668 and 2 644 genes were up-regulated in testis and ovary, respectively. We also identified 11 candidate genes related to sex determination, spermatogenesis and oogenesis. These DEGs could be classified into 1 458 GO functional classes and 132 KEGG pathways with four GO entries and two KEGG pathways significantly enriched. 【Conclusion】These results provide valuable gene expression information for the study of the molecular mechanism of reproduction in A. cerana cerana.
    Effects of feed change on intestinal bacterial composition in Bombyx mori larvae and the correlation between the key species and cocoon production performance
    ZHANG Yu-Li, ZENG Zhu, LIU Yan-Wei, LU Yu-Jia, WEI Wei, LU Cheng, CUI Wei-Zheng, BI Li-Hui, WANG Ping-Yang, ZHANG Gui-Zheng
    2022, 65(2):  176-186.  doi:10.16380/j.kcxb.2022.02.006
    Abstract ( 228 )   PDF (9657KB) ( 138 )   PDF（mobile） (9657KB) ( 17 )   　　
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    【Aim】This study aims to analyze the changes of intestinal bacterial communities in Bombyx mori larvae and the correlation between the key intestinal bacteria and the pupal weight and cocoon layer weight under different rearing patterns of artificial diet instead of mulberry leaves, so as to provide theoretical basis for the practical application of rearing B. mori by the method of partial artificial diet replacement of mulberry leaves.【Methods】B. mori larvae were reared under five different patterns including reared on mulberry leaves for all instars (Mul1-5), reared on artificial diet for the 1st-2nd instars and mulberry leaves for the 3rd-5th instars (Art1-2), reared on artificial diet for the 1st-3rd instars and mulberry leaves for the 4th-5th instars (Art1-3), reared on artificial diet for the 1st-4th instars and mulberry leaves for the 5th instar (Art1-4), and reared on artificial diet for all instars (Art1-5), and the whole cocoon weight, cocoon layer weight and pupal weight were calculated. The intestinal samples of the 5th instar larvae of B. mori under the five different rearing patterns were collected and their differences in composition and diversity of intestinal bacteria were analyzed by the high-throughput sequencing method. The correlation between the intestinal bacteria and the pupal weight and cocoon layer weight was analyzed by the Spearman correlation heatmap analysis. 【Results】The rearing patterns combining artificial diet with mulberry leaves had significant effects on cocoon quality of B. mori. The whole cocoon weight of Mull1-5 and Art1-5 was the highest, showing no significant difference, followed by that of Art1-2. The cocoon layer weight of Mul1-5 was the highest, followed by that of Art1-2, and that of Art1-5 was the lowest. The diversity and composition of intestinal bacteria in B. mori under the five rearing patterns were significantly different. At the phylum level, the bacterial composition of Art1-2 and Mul1-5 were the most similar, with the dominant bacteria of Proteobacteria and Firmicutes, while the bacterial composition of Art1-3, Art1-4 and Art1-5 was the most similar， of which the abundance of Proteobacteria gradually increased with the prolonged feeding time of artificial diet, and the abundance of Firmicutes showed an opposite trend. At the genus level, Pseudomonas, Enterococcus, Sphingomonadaceae unclassified and Ralstonia were the dominant bacteria in all groups. The abundance of the intestinal bacterial genus Enterococcus showed the largest difference in B. mori under different rearing patterns, being the highest in Art1-2 (40.9%) and decreasing gradually with the prolonged feeding time of artificial diet, and only accounting for 0.02% in Art1-5. Most of the key intestinal bacteria in B. mori were related to cocoon quality. Coxiella showed a significantly positive correlation with pupal weight, and a significantly negative correlation with cocoon layer weight. Staphylococcus was significantly negatively correlated with the pupal weight, and Enterococcus was significantly positively correlated with cocoon layer weight. 【Conclusion】The rearing pattern of Art1-2 is the closest to that of Mul1-5, which can provide reference for rearing B. mori with artificial diet partially replacing mulberry leaves. The structure of intestinal bacteria significantly change when mulberry leaves are partially replaced by artificial diet, and the significant decrease in the abundance of Enterococcus and increase of Pseudomonas may be related to the weak physique of B. mori fed with artificial diet for all instars. Some of the key bacteria are significantly correlated with pupal weight and cocoon layer weight of B. mori, although the mechanism needs further study.
    Exploration and analysis of SNP and InDel sites in Ascosphaera apis based on PacBio sequencing data
    CAI Zong-Bing, ZHANG Wen-De, LONG Qi, YU Ke-Jun, SUN Ming-Hui, WU Ying, XU Ya-Jing, LIU Jia-Mei, GUO Yi-Long, XU Xi-Jian, CHEN Da-Fu, GUO Rui
    2022, 65(2):  187-196.  doi:10.16380/j.kcxb.2022.02.007
    Abstract ( 93 )   PDF (4977KB) ( 71 )   PDF（mobile） (4977KB) ( 6 )   　　
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    【Aim】 In this study, single nucleotide polymorphism (SNP) and insertion-deletion (InDel) mutation sites were explored and analyzed using previously obtained PacBio single molecule realtime (SMRT) sequencing data of Ascosphaera apis mycelia, aiming to enrich information about SNP and InDel sites in A. apis and to provide a foundation for the development and application of new molecular markers. 【Methods】 SAMtools was employed to survey the full-length transcripts of the PacBio SMRT sequencing data of A. apis mycelia, followed by detection and analysis of SNP and InDel sites by alignment of the full-length transcripts to the reference genome of A. apis (assembly AAP 1.0) with ANNOVAR software. Genes containing SNP and InDel sites were aligned to GO database and KEGG database using related bioinformatic software to gain corresponding function and pathway annotations. 【Results】 A total of 6 743 SNP sites including 6 091 homozygous sites and 652 heterozygous sites were identified in A. apis mycelium and mainly distributed in exons, and the numbers of SNP sites with transition and transversion were 4 887 and 1 856, respectively. Additionally, the most abundant mutation type of the codon of SNP was synonymous single nucleotide mutation. Moreover, genes containing SNP sites could be annotated to 34 GO terms and 76 KEGG pathways. In total, 597 InDel sites including 349 homozygous sites and 248 heterozygous sites were identified and mainly distributed in genic downstream region, and non-frame shift insertion was the most abundant codon mutation type. Furthermore, genes containing InDel sites could be annotated to 39 GO terms and 87 KEGG pathways. 【Conclusion】 We identified a large quantity of SNP and InDel sites of A. apis, pinpointed their mutation type, distribution in genomic functional element and codon mutation type, and uncovered the potential relationship between SNP and InDel sites and the key biological processes.
    Allicin moduleates oviposition preference and fitness in Drosophila melanogaster
    ZHOU Si-Yi, XIA Jing, YAN Qin, LU Tao, CHEN Li-Rong, LIU Wei
    2022, 65(2):  197-207.  doi:10.16380/j.kcxb.2022.02.008
    Abstract ( 305 )   PDF (3434KB) ( 147 )   PDF（mobile） (3434KB) ( 22 )   　　
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    【Aim】 To study the oviposition selection of Drosophila in the presence of allicin, and to elucidate the underlying mechanism and biological significance of the oviposition avoidance of Drosophila. 【Methods】 The oviposition preference of female adults of Drosophila melanogaster to allicin at different concentrations (0.01%, 0.015% and 0.02%) was assayed by using the two-choice apparatus. The position effect of allicin on D. melanogaster was detected by oviposition apparatus. The feeding behavior of D. melanogaster was detected by capillary feeding method, and the sensory modality mediating this behavior was studied by using dark conditions, surgically removing forelegs, surgically removing antennae, and olfactory mutants. The effects of allicin on the developmental duration and survival rate of D. melanogaster offspring were investigated. The effects of 0.02%, 0.05% and 0.1% allicin on adult life span of D. melanogaster and the running speed and climbing speed of adult D. melanogaster after exposure to 0.1% allicin for 48 h were examined. The reactive oxygen species (ROS) level in intestine of D. melanogaster adults exposed to 0.02% allicin for 3 d was detected by using fluorescent dyes. 【Results】 Allicin caused oviposition avoidance in female adults of D. melanogaster. In response to 001%, 0.015% and 0.02% allicin, the oviposition indexes of female adults of D. melanogaster were -0.53, -0.77 and -0.88, respectively. D. melanogaster adults showed obvious location avoidance to allicin, with the position indexes of -0.09 and -0.22 to 0.01% and 0.015% allicin, respectively. In darkness and with foreleg removed, the female adults of D. melanogaster showed no significant oviposition avoidance to allicin. However, the female adults of D. melanogaster with antennae removed had significantly decreased oviposition avoidance to allicin, with the oviposition indexes of -0.01, -0.04 and -0.11 to 0.01%, 0.015% and 0.02% allicin, respectively. The oviposition avoidance of the mutant transient receptor potential ankyrin 1 (TrpA1) to allicin disappeared, with the oviposition indexes of -0.09, -0.06 and 0.13 to 0.01%, 0.015% and 0.02% allicin, respectively. After the eggs laid by female adults of D. melanogaster were exposed to 0.02% allicin, the time to puparium formation and time to adult eclosion of offspring were prolonged by 1.85 and 1.88 d, and the pupal and adult survival rates were decreased by 26.01% and 31.28%, respectively. Allicin at the concentrations of 0.02%, 0.05% and 0.1% shortened the life span of adult D. melanogaster and the climbing speed of adults was significantly reduced by 0.1% allicin at 48 h after treatment. Treatment of 0.02% allicin for 3 d increased the ROS level in the intestine of adult D. melanogaster. 【Conclusion】 Allicin induces oviposition avoidance in adult D. melanogaster, which is mediated mainly by olfaction system, and causes midgut damage in adult, thus reducing the growth and development of offspring and the survival rate of adults.
    Effects of landscape pattern on the community diversity of insect pollinators in jujube orchards in southern Xinjiang, northwestern China
    LI Hao, PAN Yun-Fei, YANG Long, SONG Bo-Wen, LI Qian, WANG Lan, LU Yan-Hui
    2022, 65(2):  208-217.  doi:10.16380/j.kcxb.2022.02.009
    Abstract ( 305 )   PDF (1696KB) ( 282 )   PDF（mobile） (1696KB) ( 35 )   　　
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    【Aim】To elucidate the effects of landscape pattern on the community diversity of insect pollinators in jujube orchard in southern Xinjiang, northwestern China.【Methods】A total of 29 sites were selected in Aksu, Xinjiang in 2019 and 2020, the diversity data of insect pollinators in focal jujube orchards were obtained by pan traps, and land use information within a radius of 2 000 m around focal jujube orchards was investigated. We built the linear mixed models with landscape variables and insect pollinator community index to elucidate the effect of landscape variables on insect pollinator community index in jujube orchard using multi-model inference technology based on Akaikes’ information criterion. 【Results】The proportion of other orchards (apple, walnut, pear, etc.) and semi-nature habitats (hedgerow, fallow, etc.) surrounding jujube orchards in southern Xinjiang in 2019 and 2020 were significantly negatively correlated with the abundance of insect pollinators in jujube orchards, across four scales (500, 1 000, 1 500 and 2 000 m). At the scales of 500 and 1 000 m, there was a positive correlation between the proportion of secondary crops (wheat etc.) and the species richness of insect pollinators in jujube orchards. The species richness of insect pollinators increased with edge density within the 1 000 m buffer. Landscape variables had no significant effect on the community diversity of insect pollinators in jujube orchards. 【Conclusion】 In southern Xinjiang, the abundance of insect pollinators in the jujube orchard is mainly affected by the dilution effect of the proportion of other fruit trees and semi-nature habitats, while the proportion of secondary crops can promote the increase of pollinator species richness. It is confirmed that the farmland landscape pattern can significantly affect the population of insect pollinators in Desert Oasis Agro-ecosystem in Xinjiang, which provides a scientific basis for the conservation of insect pollinators and the improvement of their pollination service function in southern Xinjiang.
    Supplementary non-host food sources significantly enhance the biocontrol potential of the thelytokous strain of Diglyphus wani (Hymenoptera: Eulophidae) against Liriomyza sativae (Diptera: Agromyzidae)
    HE Jing, YE Fu-Yu, DU Su-Jie, CHENG Xin-Fei, PAN Li-Ting, GUO Jian-Yang, WANG Fu-Lian, LIU Wan-Xue
    2022, 65(2):  218-227.  doi:10.16380/j.kcxb.2022.02.010
    Abstract ( 257 )   PDF (1512KB) ( 307 )   PDF（mobile） (1512KB) ( 6 )   　　
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    【Aim】Diglyphus wani is regard as an important biological agent of agromyzid leafminers. It could be produced by thelytoky so that all offspring are female. This is valuable for biocontrol applications. As a host-feeding parasitoid, D. wani could feed on both non-host food and host larvae in fields. In this study, the aim is to explore the effects of supplement of non-host food on biocontrol potential of thelytokous D. wani, which could provide an insight into mass rearing and biocontrol of D. wani.【Methods】The thelytokous strain of D. wani was chosen to be our study species. The late 2nd to early 3rd instar larvae of Liriomyza sativae were provided as hosts for D. wani at the constant temperature of 25℃ in the laboratory. Differences of biocontrol potential of D. wani were compared by providing three types of food ［only hosts provided (H), hosts complemented with 20% glucose solution (HGS) and hosts complemented with 20% honey solution (HHS), respectively］. 【Results】Compared with treatment of H, supplying HGS and HHS significantly increased the adult longevity of D. wani (2.4 and 2.1 fold, respectively), the number of parasitism events (3.2 and 2.9 fold, respectively), the number of host-feeding events (2.7 and 2.2 fold, respectively), and the total number of host-killing events (2.8 and 2.4 fold, respectively). Supplying HGS significantly increased the number of host-stinging events as compared with supplying H and HHS, respectively. However, there was no significant difference in the number of host-stinging events between supply of H and HHS. Besides, both supply of HGS and HHS significantly increased the daily number of parasitism events and daily total number of host-killing events, however, both treatments did not alter daily number of host-feeding events and daily number of host-stinging events yet. Moreover, no significant difference was found in the total number of host-killing events between supply of HGS and HHS. When D. wani was provided with the three types of food, the average daily total number of host-killing events was more than 17 hosts and the non-reproductive host-killing events (number of hoststinging events and host-feeding events) accounted for the largest proportion. In addition, when D. wani was provided with the three types of food, the number of host-feeding events showed significantly positive correlations with the number of parasitism events, longevity of parasitoid, and total number of host-killing events.  【Conclusion】D. wani can increase its longevity, enlarge its fecundity and further enhance the host-killing ability through host feeding. Supplementary non-host food sources can further prolong the longevity and improve the host-killing ability of D. wani. Therefore, its thelytokous strain is a promising and potential biocontrol agent against L. sativae. This study could provide guidance for the indoor rearing and field release and application of this parasitoid.
    Fitness costs to foundresses for their cooperation before oviposition in Sclerodermus guani (Hymenoptera: Bethylidae)
    ZHUANG Gui-Ling, GUO Xiao-Meng, MENG Ling, LI Bao-Ping
    2022, 65(2):  228-234.  doi:10.16380/j.kcxb.2022.02.011
    Abstract ( 323 )   PDF (1326KB) ( 94 )   PDF（mobile） (1326KB) ( 8 )   　　
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    【Aim】Sclerodermus foundresses can cooperate to parasitize hosts. Before oviposition, they need to sting the host and release venoms to immobilize it. It has been known that the cooperation enhances the efficacy of subduing and parasitizing strongly defensive hosts with a large body size. It is not yet known of fitness costs thereon incurred to the wasp for the cooperation. 【Methods】The experiment was conducted on the parasitoid S. guani with the flour beetle, Tenebrio moliter pupa as the substitutive host. Two mated female wasps (foundresses) were allowed to colonize together on a single host for different cooperation periods (0.5, 1.5, or 2.5 d) and then randomly retained one to continue the following parasitism on the host as the beneficiary foundress, while transferred another to a new host to make another parasitism as the altruistic foundress. The survival, oviposition, and offspring developmental performances were compared between the beneficiary and altruistic foundresses. 【Results】The odds of death of the altruistic foundress of S. guani were 5.4 times higher than those of the beneficiary foundress, regardless of the cooperation period. The pre-oviposition time was not different between the beneficiary and altruistic foundresses after the 0.5 d cooperation, while the altruistic foundress had 14.1% and 28.6% shorter pre-oviposition time than the beneficiary foundress after the cooperation of 1.5 d and 2.5 d, respectively. The two foundresses did not differ in the number of eggs laid, number of offspring emerged to adulthood, and offspring sex ratio (proportion of male offspring). Regardless of the cooperation period, the egg duration and larval duration of offspring of the beneficiary foundress were 6.8% and 8.4% longer than those of the altruistic foundress, respectively. The body weight of female offspring adults at emergence was similar between the two foundresses after the cooperation of 0.5 d and 1.5 d but the altruistic foundress had 25.4% less body weight than the beneficiary foundress after the 2.5 d cooperation. 【Conclusion】The results of this study suggest that S. guani foundresses incur fitness costs to their survival and some of their offspring development performances, especially for a longer period of cooperation before oviposition.
    Natural barriers and climatic oscillation in the Quaternary Pleistocene influence the phylogeography of Sigmella biguttata (Blattodea: Ectobiidae) revealed by mitochondrial and nuclear genes (In English)
    CHEN Rong, NIU Li-Kang, DUANMU Hao-Nan, WANG Zong-Qing, CHE Yan-Li
    2022, 65(2):  235-245.  doi:10.16380/j.kcxb.2022.02.012
    Abstract ( 229 )   PDF (12984KB) ( 151 )   PDF（mobile） (12984KB) ( 27 )   　　
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    【Aim】This study aims to clarify the genetic differentiation among populations and to reveal the cause of the geographical distribution pattern of Sigmella biguttata. 【Methods】 The sequences of mitochondrial genes COI, COII and ND1 and nuclear gene ITS of 284 individuals from 19 geographic populations of S. biguttata were amplified by PCR. The genetic diversity and genetic differentiation of S. biguttata geographic populations were analyzed using MEGA v.7.0, DnaSP v.5.0 and Arlequin v.3.5, and the population historical dynamics was detected by neutrality test and mismatch distribution analysis. The phylogenetic trees were constructed using maximum likelihood (ML) and Bayesian inference (BI) methods and the haplotype network was constructed using median joining network algorithm. The divergence time of S. biguttata populations was inferred based on the substitution rate of mitochondrial gene COI.【Results】The overall genetic diversity of the geographic populations of S. biguttata was relatively high (Hd=0.98835, π=0.02777). The ML and BI trees yielded almost identical topologies with generally high support values, and all geographic populations of eight groups were clustered together to form three lineages and showed obvious phylogeographic structure, which was consistent with the result of SAMOVA analysis. There was no haplotype shared by different geographic populations according to the haplotype network. The genetic differentiation and gene flow (Nm) analysis showed that the Fst values among populations were more than 0.25 and the maximum Nm value was less than 1. The population historic dynamics analysis showed that Group 2, Group 4, Group 6 and Group 7 experienced population expansion, occurring in the last interglacial period, but Group 1, Group 3, Group 5 and Group 8 did not. The divergence time of lineages and groups was estimated in the Mid-Pleistocene (0.5391-0.1544 Ma). 【Conclusion】 There is significant genetic differentiation among populations of S. biguttata. A warm and humid climate contributes to the population expansion of S. biguttata, and the genetic structure and geographic distribution pattern of the populations are mainly affected by geographic barriers and climatic oscillation in the Quaternary Pleistocene.
    REVIEW　ARTICLES
    Studies and applications of gene editing technology in insects
    QIU Yu-Hao, JIA Yu, NI Jian-Quan, WANG Bing, WANG Gui-Rong
    2022, 65(2):  246-256.  doi:10.16380/j.kcxb.2022.02.013
    Abstract ( 478 )   PDF (1487KB) ( 622 )   PDF（mobile） (1487KB) ( 70 )   　　
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     The development of gene editing technology is of great significance for the study of physiological functions such as growth, development and reproduction of insects, as well as the mechanism of behavior manipulation. In this article, we introduced the development history of gene editing technology, and described the principles of zinc finger nuclease (ZFN), transcription activator-like effector nuclease (TALEN), and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) protein 9 (CRISPR/Cas9) system-mediated gene site-editing technologies. In the model insect Drosophila, the third-generation gene editing technology is continuously upgraded and optimized. It has such advantages as high editing efficiency, heritability, and facilitating screening, which helps to reveal the mechanism of key signal pathways in cell biology, developmental biology and neurobiology. In the medical vector insect mosquito, the CRISPR/Cas9 system-mediated gene editing technology has important research value in reducing pesticide resistance, and controlling the population and epidemic spread of mosquito-borne diseases. In the study of agricultural pests, the use of gene editing technology can perform the in vivo functional characterization of the key molecular targets in multiple signaling pathways, providing a new idea for pest management. In the study of beneficial insects, gene editing technology is mainly applied to studying sex regulation and antiviral ability of Bombyx mori, and improving silk quality. Finally, we debate the future prospects for the study of the gene editing technology in insects: (1) to optimize gene editing systems to improve editing efficiency; (2) to develop new gene regulation tools; and (3) to construct transgenic insect strains, in order to provide references for the analysis of insect gene function, the improvement of economic insects, and the control of major pests.
    CONTENTS
    Contents of Vol. 65 Issue 2
    2022, 65(2):  257-257. 
    Abstract ( 140 )   PDF (517KB) ( 71 )   PDF（mobile） (517KB) ( 10 )   　　
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