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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 2021, Volume 64 Issue 2
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  • RESEARCH PAPERS
    Effects of RNAi-mediated suppression of Br-Z2/3 gene on the expression of downstream apoptotic genes and pupation in the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)
    HU Xiao-Han, TIAN Su-Fen, LI Ya-Qing, LIN Shuo, CHEN Yi-Xin, WEI Hui, GU Xiao-Jun, HUANG Jing-Fei, WANG Xi-Ying, LI Zhi-Hua
    2021, 64( 2):  141-148.  doi:10.16380/j.kcxb.2021.02.001
    Abstract ( 418 )   PDF (3456KB) ( 183 )   PDF(mobile) (3456KB) ( 50 )     
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    【Aim】 This study aims to establish an in vitro prokaryotic expression system for synthesis of the dsRNA of pupa-specific expression gene Br-Z2/3 from the diamondback moth, Plutella xylostella, and to find out the effects of RNAi-mediated suppression of Br-Z2/3 on the expression of Br-Z2/3 and apoptotic genes and the pupation of the moth. 【Methods】 The L4440-Br-Z2/3 recombinant vector was constructed and transformed into competent cells of Escherichia coli HT115. The dsRNA of Br-Z2/3 was obtained after induction with IPTG, and RNAi was carried out by microinjecting Br-Z2/3 dsRNA into the 4th instar larvae of P. xylostella. At 12 and 24 h after RNAi of Br-Z2/3, the expression levels of Br-Z2/3 and its downstream apoptotic genes, reaper, caspase-9 and Gadd45g, were detected through qPCR. Simultaneously, the pupation rate, average pupation time, rate of deformed pupae and larval mortality of the 4th instar larvae of P. xylostella after RNAi of Br-Z2/3 were observed and recorded. 【Results】 The dsRNA of Br-Z2/3 was successfully expressed in the prokaryotic system. The qPCR results showed that the expression levels of Br-Z2/3 and the related apoptotic gene reaper decreased significantly, but those of caspase-9 and Gadd45g increased significantly after RNAi of Br-Z2/3 in the 4th instar larvae of P. xylostella. Compared with the control group, the dsBr-Z2/3-injected group showed significantly lower pupation rate with delayed pupation peak, and had significantly higher mortality and higher rate of deformed pupae. 【Conclusion】 An in vitro prokaryotic expression system for synthesis of the dsRNA of Br-Z2/3 from P. xylostella was successfully established. RNAi of Br-Z2/3 by microinjection demonstrates that Br-Z2/3 plays a crucial role in the pupation of P. xylostella.
    Prokaryotic expression, antibody preparation and expression profiling of the odorant binding protein AdisOBP6 in Athetis dissimilis (Lepidoptera: Noctuidae)
    SONG Yue-Qin, SONG Zhi-Yu, DONG Jun-Feng, CHEN Qing-Xiao, SUN Hui-Zhong
    2021, 64( 2):  149-157.  doi:10.16380/j.kcxb.2021.02.002
    Abstract ( 295 )   PDF (5673KB) ( 92 )   PDF(mobile) (5673KB) ( 13 )     
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    【Aim】 This study aims to carry out prokaryotic expression, antibody preparation and expression profiling of the odorant binding protein OBP6 in Athetis dissimilis, so as to facilitate the future study on the function of AdisOBP6. 【Methods】Bioinformatics software was used to analyze the structure characteristics of AdisOBP6 protein. AdisOBP6 antibody was prepared by immunizing New Zealand white rabbits four times using the recombinant protein obtained by prokaryotic expression. Fluorescence quantitative PCR and Western blot were used to detect the expression profiles of AdisOBP6 in the antennae of female and male adults, testes at different developmental stages and unfertilized and fertilized eggs of A. dissimilis. 【Results】 Homologous modeling prediction showed that AdisOBP6 has six conserved cysteine residues and seven α-helical structures, which are folded into a binding pocket. The prokaryotic expression results showed that the recombinant protein was expressed most highly and stably under induction with 0.5 mmol/L IPTG at 20℃. Antibody titers exceeded 1∶512 000, 1∶512 000, 1∶512 000, and 1∶64 000, respectively, in four immune replicates. The specific binding of the obtained antibody to AdisOBP6 protein was detected by Western blot. Fluorescence quantitative PCR results showed that the expression level of AdisOBP6 in the testis was much higher than that in the antennae. AdisOBP6 began to express in the testis of A. dissimilis at the larval stage, with a higher expression level in the larval testis than in the pupal testis, and its expression level gradually reached the peak in the testis of adults after eclosion, but it was scarcely expressed or expressed at a very low level in unfertilized eggs and fertilized eggs. Western blot analysis showed that AdisOBP6 protein was also mainly expressed in the testis, and its expression level was very low in the antennae of female and male adults, fertilized eggs and unfertilized eggs. 【Conclusion】 In this study, the prokaryotic expression of AdisOBP6 was realized, and its antibody was successfully prepared. This study also confirmed that AdisOBP6 is highly expressed in the testis, and the expression level of AdisOBP6 reaches the peak after adult eclosion, suggesting that AdisOBP6 may be involved in insemination process. These results lay a foundation for further studying the function of AdisOBP6.

    cDNA cloning and expression profiling of the odorant binding protein AsinOBP2 in Anopheles sinensis (Diptera: Culicidae) and analysis of its binding characteristics with human odorants
    ZHANG Jia-Jun, HE Xing-Fei, ZHANG Ting-Ting, SI Feng-Ling, CHEN Bin, HE Zheng-Bo
    2021, 64( 2):  158-169.  doi:10.16380/j.kcxb.2021.02.003
    Abstract ( 242 )   PDF (3323KB) ( 81 )   PDF(mobile) (3323KB) ( 23 )     
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     【Aim】 This study aims to clone the odorant binding protein 2 gene AsinOBP2 of Anopheles sinensis, and to analyze the expression profiles of AsinOBP2 and the binding affinities of its recombinant protein with human odorants. 【Methods】 The full-length cDNA sequence of AsinOBP2 was cloned by RT-PCR and RACE techniques. The expression levels of AsinOBP2 in different developmental stages (female and male pupa, and 0-, 1-, 2, 3-, 6- and 9-day-old adults), different chemosensory tissues (antenna, proboscis and maxillary palp) of the 3-day-old adult, and the 3-day-old female adults before and post blood meal were measured by qPCR. The recombinant protein AsinOBP2 was expressed and purified by prokaryotic expression and affinity chromatography, respectively. The binding affinities of the recombinant AsinOBP2 with 39 human odorants were analyzed using fluorescence competitive binding assay. 【Results】 The full-length cDNA of AsinOBP2 (GenBank accession no.: MT700441) was successfully cloned and sequenced. Its ORF is 492 bp in length, encoding 163 amino acids with the signal peptide of 30 amino acids at the N-terminus. The mature protein possesses six conserved cysteines and belongs to the Classic OBP subfamily. The qPCR results showed that the expression level of AsinOBP2 in adults gradually increased with the eclosion time, peaked on the 6th day after eclosion, and then went down. AsinOBP2 was mainly expressed in the antenna of female adult mosquito. The expression level of AsinOBP2 in the 3-day-old female adult decreased significantly after blood meal. The results of fluorescence competitive binding assay showed that among the 39 human odorants tested, the recombinant AsinOBP2 had binding activities with 12 compounds. AsinOBP2 had a higher binding affinity to indole, with the dissociation constant Ki value of 27.15 μmol/L, followed by n-propylamine, 2methylbutanal and decanal with the Ki values of 42.49, 48.33 and 47.90 μmol/L, respectively. 【Conclusion】 Based on the expression profiles of AsinOBP2 and the binding affinities of its recombinant protein to human odorants, which indicated that AsinOBP2 has obviously selective binding properties to human odorants, we inferred that AsinOBP2 plays an important role in host-seeking behavior of female mosquito.

    Effects of the serine protease homologue SgSPH from the venom of Scleroderma guani (Hymenoptera: Bethylidae) on the phenoloxidase activity in the host hemolymph
    LI Li-Fang, WU Chao-Yan, HAN Kai-Jian, WU Guo-Xing, ZHU Jia-Ying
    2021, 64( 2):  170-177.  doi:10.16380/j.kcxb.2021.02.004
    Abstract ( 328 )   PDF (1595KB) ( 51 )   PDF(mobile) (1595KB) ( 9 )     
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    【Aim】 The aim of this study is to clone and express the venom serine protease homologue (SPH) gene of Sclerotium guani (SgSPH), and to investigate the effect of the venom protein encoded by this gene on the phenoloxidase activity in the host hemolymph. 【Methods】 The open reading frame (ORF) of venom SgSPH gene was cloned from S. guani by RT-PCR. Its sequence features were analyzed using bioinformatic software. The relative expression levels of the venom SgSPH gene at different developmental stages (egg, early instar larva, late instar larva, mature larva, spinning larva, pupa in yellow cocoon, pupa in black cocoon, and 1-5-day-old adults) and in different female adult tissues (head, thorax, abdomen without venom apparatus and venom apparatus) of S. guani were determined by qPCR. This venom gene was expressed with prokaryotic expression vector pSUMO-Mut. The expressed recombinant protein was purified using Ni-chelating affinity chromatography, and examined by SDS-PAGE and Western blot analysis. The inhibitory effect of the recombinant SgSPH on the phenoloxidase activity in the pupal haemolymph of Tenebrio molitor was measured by enzymatic activity assay. 【Results】 The ORF of the venom SgSPH gene (GenBank accession number: MT920663) of S. guani was cloned. It is 798 bp in length, encoding 265 amino acids, with the signal peptide consisting of amino acids 1-20, and the predicted protein molecular mass of 30.53 kD and pI of 9.59. Multiple sequence alignment results showed that SgSPH of S. guani shares low amino acid sequence identity (9%-17%) with the serine proteases and SPHs from venoms of other parasitoid wasps, and lacks a conservative catalytic triad. The qPCR results indicated that SgSPH gene was abundantly expressed at the adult stage and in the venom apparatus of S. guani. SDSPAGE and Western blot analyses showed that the recombinant SgSPH was successfully expressed and the highly purified recombinant SgSPH was obtained. Enzymatic activity assay results showed that the recombinant SgSPH was able to inhibit the phenoloxidase activity in the pupal hemolymph of the host T. molitor. 【Conclusion】 The results suggest that the venom SgSPH of S. guani can interfere with the host phenoloxidase cascade.

    Expression and ligand binding characterization of the odorant binding protein AcerOBP14 of Apis cerana cerana
    PENG Zhu, HUANG Li, ZHAO Shu-Guo, LÜJian-Hua, ZHAO Hui-Ting
    2021, 64( 2):  178-186.  doi:10.16380/j.kcxb.2021.02.005
    Abstract ( 404 )   PDF (2224KB) ( 80 )   PDF(mobile) (2224KB) ( 27 )     
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    【Aim】 Odorant binding proteins (OBPs) play an important role in host localization, egg-laying site selection and other behaviors of insects. Clarifying the binding characteristics of AcerOBP14 with ligands helps to elucidate the molecular mechanism of olfactory recognition in Apis cerana cerana. 【Methods】 The expression levels of OBP14 in the antennae of the 20-day-old adult workers and drones of A. c. cerana and pollen foragers of A. c. cerana and Apis mellifera ligustica were detected by qRT-PCR. The prokaryotic expression vector pET28a/AcerOBP14 was constructed, and the recombinant AcerOBP14 protein was expressed and purified. The binding characteristics of AcerOBP14 with 37 odorant compounds were analyzed by fluorescence competition binding assay. 【Results】 The qRT-PCR analysis revealed that the expression level of OBP14 in the antennae of pollen foragers of A. c. cerana was significantly higher than those in the antennae of the 20-day-old adult workers and drones of A. c. cerana and pollen foragers of A. m. ligustica. Fluorescent competition binding assay results showed that AcerOBP14 had the binding ability with queen bee pheromone, alarm pheromone, Nasonov pheromone and a variety of plant volatiles, and showed the strongest binding ability to β-ocimene with the dissociation constant Ki value of 0.297 μmol/L. 【Conclusion】 AcerOBP14 has a broad ligand-binding spectrum, suggesting that it may be involved in a variety of physiological and behavioral responses of A. c. cerana, and play an important role in the pollen foraging behavior of A. c. cerana.
    Omics analysis of Nosema ceranae miRNAs involved in gene expression regulation in the midgut of Apis mellifera ligustica workers and their regulatory networks#br#
    FAN Xiao-Xue, DU Yu, ZHANG Wen-De, WANG Jie, JIANG Hai-Bin, FAN Yuan-Chan, FENG Rui-Rong, WAN Jie-Qi, ZHOU Zi-Yu, XIONG Cui-Ling, ZHENG Yan-Zhen, CHEN Da-Fu, GUO Rui
    2021, 64( 2):  187-204.  doi:10.16380/j.kcxb.2021.02.006
    Abstract ( 264 )   PDF (39131KB) ( 50 )   PDF(mobile) (39131KB) ( 18 )     
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    【Aim】 Based on the previously gained miRNA and mRNA omics datasets, bioinformatic prediction, database annotation and regulatory network analysis of differentially expressed mRNAs (DEmRNAs) in the midgut of Apis mellifera ligustica workers targeted by differentially expressed miRNAs (DEmiRNAs) of Nosema ceranae were conducted in this study, aiming to uncover the regulation of gene expression in the midgut of A. m. ligustica by N. ceranae. 【Methods】 Significant DEmRNAs of A. m. ligustica workers were screened by comparison of miRNA data from the midgut of A. m. ligustica workers at 7 d (AmT1) and 10 d (AmT2) post N. ceranae infection and the corresponding uninfected midguts (AmCK1 and AmCK2, respectively), while significant DEmiRNAs of N. ceranae were screened through comparison of miRNA data from N. ceranae infecting the midgut of A. m. ligustica workers (NcT1 and NcT2, respectively) and clean fungal spores (NcCK). DEmRNAs in the midgut of A. m. ligustica workers targeted by N. ceranae DEmiRNAs were predicted using TargetFinder software. GO and KEGG database annotations of the aforementioned target DEmRNAs in the midgut of A. m. ligustica workers were performed with related bioinformatic tools. Following KEGG database annotations, DEmRNAs in the midgut of A. m. ligustica workers relative to immune defense and energy metabolism were filtered out, followed by construction and investigation of the regulatory networks between the abovementioned DEmRNAs in the midgut of A. m. ligustica workers and the corresponding N. ceranae DEmiRNAs. 【Results】 In the NcCK vs NcT1 comparison group, 77 significantly up-regulated miRNAs and 52 significantly down-regulated miRNAs of N. ceranae could respectively target 118 significantly down-regulated mRNAs and 135 significantly up-regulated mRNAs in the midgut of A. m. ligustica workers in the AmCK1 vs AmT1 comparison group, and these mRNAs could be annotated to 31 and 25 GO terms and 113 and 107 KEEG pathways, respectively. In the NcCK vs NcT2 comparison group, 52 significantly up-regulated miRNAs and 49 significantly down-regulated miRNAs of N. ceranae could respectively target 97 significantly down-regulated mRNAs and 210 significantly up-regulated mRNAs in the midgut of A. m. ligustica workers in the AmCK2 vs AmT2 comparison group, and these mRNAs could be annotated to 27 and 30 GO terms and 97 and 127 KEGG pathways, respectively. Moreover, 11 shared significantly up-regulated miRNAs and 19 shared significantly down-regulated miRNAs in the NcCK vs NcT1 and NcCK vs NcT2 comparison groups could respectively target six shared significantly down-regulated mRNAs and 14 shared significantly up-regulated mRNAs in the midgut of A. m. ligustica workers in the AmCK1 vs AmT1 and AmCK2 vs AmT2 comparison groups, which could be annotated to 7 and 10 GO terms and 0 and 9 KEEG pathways, respectively. DEmiRNAs in the NcCK vs NcT1 and NcCK vs NcT2 comparison groups could target DEmRNAs associated with energy metabolism pathways including oxidative phosphorylation and sulfur metabolism, and immune defense pathways such as endocytosis, melanogenesis, lysosome, autophagy, Toll-like receptor signaling pathway, apoptosis, Ras signaling pathway, ubiquitin-mediated proteolysis, and MAPK signaling pathway in the midgut of A. m. ligustica workers in the AmCK1 vs AmT1 and AmCK2 vs AmT2 comparison groups. Further analysis indicated that miR-216-x, miR-5119-y, bantam-y and miR-8-y were all significantly up-regulated in both the NcCK vs NcT1 and NcCK vs NcT2 comparison groups, and targeted several significantly down-regulated mRNAs relative to immune defense pathways such as lysosome, melanogenesis, ubiquitin-mediated proteolysis, MAPK signaling pathway and Ras signaling pathway in the midgut of A. m. ligustica workers. 【Conclusion】 DEmiRNAs of N. ceranae may exert extensive effects on gene expression in A. m. ligustica workers during the infection process. N. ceranae is likely to enhance its infection through cross-kingdom regulation of immune defense of A. m. ligustica workers via up-regulating some miRNAs, and increase energy stealing and proliferation by cross-kingdom regulation via down-regulating some miRNAs.
    Influence of two surfactants on the infection of Isaria fumosoroseus strain PF904 on Plutella xylostella (Lepidoptera: Plutellidae) larvae#br#
    WANG Hong-Min, ZHAO Yi-Tao, GUO Heng, ZHANG Xian-Hong
    2021, 64( 2):  205-212.  doi:10.16380/j.kcxb.2021.02.007
    Abstract ( 263 )   PDF (11408KB) ( 51 )   PDF(mobile) (11408KB) ( 9 )     
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    【Aim】 Based on our previous screening tests, this study aims to compare the synergism of surfactants on the infection of Isaria fumosoroseus strain PF904 on the 3rd instar larvae of Plutella xylostella, and to screen the suitable adjuvant to improve the control efficacy of I. fumosoroseus PF904. 【Methods】 After the 3rd instar larvae of P. xylostella were sprayed with the spore suspension of I. fumosoroseus PF904 added with the surfactants PEG-12 dimethicone (OFX-0193) (final concentration 125 mg/L) and naphthalenesulfonicacid, dibutyl-, sodium salt (Nekal) (final concentration 250 mg/L), respectively, the number of attached conidia of I. fumosoroseus PF904 on the larval body surface and the infection rate and pathogenicity of I. fumosoroseus PF904 against the larvae were determined by observation with scanning electron microscopy and laboratory pathogenicity test. 【Results】 Adding 250 mg/L Nekal and 125 mg/L OFX-0193, significantly increased the number of attached conidia of I. fumosoroseus PF904 at various structural areas on the body surface of the 3rd instar larvae of P. xylostella. The numbers of conidia attached to spinous structural area, gentle structural area and acanthoid structural area on the body surface of the 3rd instar larvae of P. xylostella exposed to the spore suspension of I. fumosoroseus PF904 with 250 mg/L Nekal were 2.19, 1.78 and 1.94 times as high as that of the control (spore suspension added with water), respectively, indicating that Nekal increases the adhesion rate of I. fumosoroseus PF904 spores. Adding 250 mg/L Nekal and 125 mg/L OFX-0193, significantly reduced the conidial germination time, promoted the formation of appressorium and increased the infection rate of I. fumosoroseus PF904. The results of laboratory pathogenicity test showed that adding 250 mg/L Nekal and 125 mg/L OFX-0193, significantly increased the pathogenicity of the spore suspension of I. fumosoroseus PF904 against the 3rd instar larvae of P. xylostella. After exposure to the spore suspension of I. fumosoroseus PF904 with 250 mg/L Nekal, the corrected mortality rate of the 3rd instar larvae of P. xylostella was 79.2% and the median lethal time (LT50) was reduced to 2.71 d, indicating that Nekal has a significant synergistic effect. 【Conclusion】 Nekal at the concentration of 250 mg/L is a suitable adjuvant for I. fumosoroseus PF904 to improve its control efficacy against P. xylostella larvae.
    Brochosome detachment facilitates Empoasca onukii (Hemiptera: Cicadellidae) adults escaping from spider web#br#
    LIN Mei-Zhen, YANG Guang, WANG Zhen-Yan, YOU Min-Sheng
    2021, 64( 2):  213-222.  doi:10.16380/j.kcxb.2021.02.008
    Abstract ( 344 )   PDF (19162KB) ( 68 )   PDF(mobile) (19162KB) ( 16 )     
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    【Aim】 The tea green leafhopper, Empoasca onukii, is a significant pest in tea plantations in China. Its body surface is covered with brochosomes. However, little is known about the defense function of brochosomes. This study aims to clarify the role of brochosome detachment in the escape of tea leafhoppers from spider webs. 【Methods】 E. onukii adults were thrown into lacy webs of Hylyphantes graminicola, and the behavior parameters and escape details of E. onukii adults in the presence and absence of spiders were analyzed by using high definition video camera and Vegas software. Touching of brochosomes on the wings of E. onukii adults with threads of spider webs was observed by the scanning electron microscope (SEM), and the distribution of brochosomes on body parts of escaping E. onukii adults contacting spider web was also analyzed. 【Results】 The escape rates of E. onukii adults from the webs within 60 min in the presence of spiders and in the absence of spiders were 45.0% and 76.7%, respectively. The escape time of adults from the webs in the presence of spiders was remarkably shorter than that in the absence of spiders. There were at least four different strategies for adults to escape from spider web. In both the groups with the presence and absence of spiders, the rolling rate was about 80% and the rolling time was approximately 0.5 s, suggesting that the adhesion force between the wing of E. onukii adults and spider web is small. The escape time of E. onukii adults was approximately 3 times as long as the rolling time. The body parts of E. onukii adults most uneasy to detach from spider web were forelegs and middle legs, which was inferred from the struggle behaviors and detaching parts of E. onukii adults from spider web. The SEM images showed that the wings of E. onukii adults were the parts most uniformly and densely distributed with brochosomes, with the covering density of 280±17 particles/25 μm2. Brochosomes can be detached from wings and enfold a whole viscous capture thread. Brochosomes distributed on the femur and pretarsi of foreleg were non-uniform, with the covering density as low as 4±4 particles/25 μm2 on the bare parts, which might be the reason that the foreleg of the insect is uneasy to detach from viscous capture threads. 【Conclusion】 The detachment of brochosomes covering the body surface of E. onukii adults can facilitate leafhopper adults escaping from spider web, and whether the leafhopper adults can escape quickly from spider web or not depends on the presence of brochosomes on the contacting parts.
    Foraging and predation behaviors of the harlequin ladybird, Harmonia axyridis (Coleoptera: Coccinellidae), on the alien cotton mealybug Phenacoccus solenopsis (Hemiptera: Pseudococcidae) coexisting with a native aphid#br#
    LIU Jing-Ya, LI Zhuo-Miao, LI Bao-Ping, MENG Ling
    2021, 64( 2):  223-229.  doi:10.16380/j.kcxb.2021.02.009
    Abstract ( 254 )   PDF (1806KB) ( 68 )   PDF(mobile) (1806KB) ( 16 )     
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    【Aim】 The alien invasive species as prey may influence the foraging and predation behaviors of native generalist predators. This study aims to clarify the foraging and predation behaviors of the harlequin ladybird (Harmonia axyridis) on the alien cotton mealybug (Phenacoccus solenopsis) co-existing with a native bean aphid (Megoura japonica). 【Methods】 Two feeding treatments were previously applied to H. axyridis, in which H. axyridis ladybirds were fed with P. solenopsis and M. japonica, respectively, for more than three generations before the experiment and thus referred to as mealybug-fed and aphid-fed ladybirds, respectively. Vicia faba seedlings were provided as substrates, on which one prey combination patch on a leaf was set up and exposed to one individual of the 4th instar larva of H. axyridis that had been starved for 24 h, and the patch consisted of both the 3rd instar nymphs of P. solenopsis and the 3- or 4-day-old nymphs of M. japonica with mealybugs accounting for 5.6%-83.3% in total 20-30 individuals (specific numbers were determined at random). The ladybird larva was thereafter followed for 2 h to record its first attack of prey and the proportions of consumed mealybugs in the total number of prey, searching time in the total time, and prey-handling time in the total searching time. Regression models were applied to determine the probability of the first attack on mealybugs and other observed variables as a function of previously fed prey species and the proportion of available mealybugs in the patch. 【Results】 The 4th instar larva of H. axyridis increased the probability of making its first attack on mealybugs with the proportion of available mealybugs, increased by 77.2% for each 10% increase in the proportion of available mealybugs; however, this probability was not influenced by the species of previously fed prey. The relationship between the proportion of mealybugs in the total prey consumed by H. axyridis and the proportion of available mealybugs depended on the species of previously fed prey: the proportion of consumed mealybugs increased by 137% for the ladybird that was previously fed with mealybugs while by 60% as fed with aphids with each 10% increase in the proportion of available mealybugs. The proportion of searching time in the total foraging time of H. axyridis was influenced by the proportion of available mealybugs but not by the species of previously fed prey, being increased by 13% with each 10% increase in the proportion of available mealybugs and slightly reduced by 7% for the ladybird previously fed with mealybugs as opposed to that with aphids. The proportion of mealybughandling time among the total foraging time of H. axyridis was influenced by the proportion of available mealybugs but not by the species of previously fed prey, being increased by 41% for each 10% increase in the proportion of available mealybugs. 【Conclusion】 The results of this study suggest that H. axyridis may exercise a prey frequency-dependent predation on P. solenopsis coexisting with native aphids in a patch, and such dependence may become stronger if it has the experience of predation on the mealybug.
    Feeding preference and adaptability of Spodoptera frugiperda (Lepidoptera: Noctuidae) on different wheat cultivars in relation to leaf biochemical contents#br#
    LIU Huan, ZHANG Yong, CHEN Ju-Lian
    2021, 64( 2):  230-239.  doi:10.16380/j.kcxb.2021.02.010
    Abstract ( 454 )   PDF (1662KB) ( 129 )   PDF(mobile) (1662KB) ( 33 )     
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    【Aim】 This study aims to determine the feeding preference and adaptability of the fall armyworm (FAW), Spodoptera frugiperda, on different wheat cultivars collected from the Huang-Huai-Hai wheat growing areas in North China, to explore the relationship between insect pest damage and wheat cultivars, and to clarify the resistance levels of different wheat cultivars to FAW, so as to provide a theoretical basis for the arrangement of insect resistant cultivars and integrated pest management in wheat fields. 【Methods】 The feeding preference of the 1st and 3rd instar larvae of FAW to 15 wheat cultivars was compared. Four wheat cultivars with high feeding preference and two wheat cultivars with low feeding preference for the 1st and 3rd instar larvae of FAW were screened out, the contents of biochemical components (total protein, soluble sugar, total phenol and tannin) in leaves of these six wheat cultivars were determined, the relationship between the feeding preference of the larvae and the contents of biochemical components in leaves of these six wheat cultivars was clarified by Pearson correlation analysis, and the adaptability of FAW on the six wheat cultivars was observed. 【Results】 The results revealed that the 1st and 3rd instar larvae of FAW preferred to feeding on Huaimai 46, Huaimai 33, KOK1679 and Tongmai 6, but not on Luyuan 502 or Yannong 21. The feeding preference of the 1st and 3rd instar larvae to leaves of different wheat cultivars was positively correlated with the total protein content and the soluble sugar content in wheat leaves, but negatively correlated with the total phenol content and the tannin content. The development of FAW was significantly different on leaves of different wheat cultivars, with the highest host suitability index and the shortest larval duration on Tongmai 6, and with the longest larval duration on Yannong 21. 【Conclusion】 The FAW showed different adaptability to different wheat cultivars, and Yannong 21 showed higher resistance to this insect pest. The FAW larvae prefer wheat leaves with higher contents of total protein and soluble sugar, while the feeding can be inhibited by high contents of total phenol and tannin in wheat leaves. It is speculated that the difference of resistance levels of different wheat cultivars to FAW is resulted from the coordination of nonpreference and antibiosis in wheat by the metabolism of nutrients and secondary substances.
    Biological characteristics of adult Aphelinus maculatus (Hymenoptera: Aphelinidae)
    LI Ke-Zhuo, FENG Shu-Jun, ZHAO Yan-Li, DUAN Li-Qing
    2021, 64( 2):  240-249.  doi:10.16380/j.kcxb.2021.02.011
    Abstract ( 340 )   PDF (10023KB) ( 81 )   PDF(mobile) (10023KB) ( 18 )     
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    【Aim】 Aphelinus maculatus is one of the important parasitic wasps parasitizing on the cotton aphid, Aphis gossypii, discovered in recent years. There is little study on the biological characteristics including behavior and habits of Ap. maculatus so far. In order to explore and utilize this wasp effectively, it is important to ascertain its biological characteristics. 【Methods】 The emergence rhythm, mating behaviors, duration of various stages of mating, mating frequency, mating competition, sex ratio of offsprings reproduced by different reproductive modes, and longevity of adult Ap. maculatus were observed and recorded under microscope in the laboratory, and the parasitization process of this parasitoid on A. gossypii nymphs, the ovipositor insertion time of Ap. maculatus adults when parasitizing and feeding on A. gossypii, and the parasitization and feeding selection of Ap. maculatus adults to different day-old nympyhs of A. gossypii were also observed. 【Results】 Ap. maculatus adults emerge mainly at 6∶00-10∶00 am. Female and male adults mate on the day of emergence. The mating process can be divided into four phases: courtship, precopulation, copulation and postcopulation. The copulation duration is short, only lasting for 5.5±0.2 s. One male can copulate with 2-4 unmated females within 3 h, while the female only copulate once. Mating competition occurs among females and also among males. Ap. maculatus can reproduce offspring by parthenogenesis and amphigenesis. Only male offsprings are reproduced by parthenogenesis, but both female and male offsprings by amphigenesis. The parasitization process can be divided into such steps as searching host, examining host, probing insertion site, parasitic oviposition or feeding host, and cleaning and carding. The decision of parasitic oviposition or host feeding is related to the ovipositor insertion time into aphid body. When the ovipositor insertion time is longer than 4.8 min, adult wasps are more likely to feed host. Ap. maculatus wasps prefer to feed the early instar nymphs of A. gossypii, rarely feed 4 d or 5 dold nymphs, but can parasitize different dayold nymphs of A. gossypii. One female wasp can parasitize 14.8 A. gossypii nymphs and feed 3.7 A. gossypii nymphs on the average within 24 h. The adult longevity of Ap. maculatus is related to nutrient supplement after adult emergence. Adult wasps fed 10% sucrose and 10% honey could live 24±2.5 d and 28±1.6 d, respectively. 【Conclusion】 Ap. maculatus can reproduce by parthenogenesis and amphigenesis. Mating competition occurs among both females and males. The adult longevity of Ap. maculatus can be prolonged by supplying sucrose or honey.
    REVIEW ARTICLES
    Research progress of Notch signaling pathway in insects
    YANG Xi, CHEN Peng, JIANG Xia, PAN Min-Hui, LU Cheng
    2021, 64( 2):  250-258.  doi:10.16380/j.kcxb.2021.02.012
    Abstract ( 309 )   PDF (2353KB) ( 93 )   PDF(mobile) (2353KB) ( 16 )     
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    Composed of the Notch receptor, the Notch ligand (DSL protein), the CSL [C promoter binding factor-1 (CBF1), Suppressor of hairless (Su(H)), Lag-1] transcription factors, other effectors, and the regulatory molecules of Notch, Notch signaling pathway plays a fundamental role in the development of tissues in animals and the decision of cell fate in organs. Since its discovery in Drosophilia in 1917, the research on Notch signaling pathway based on insects has been very active, and it has been proved that it mainly plays fundamental roles in embryo and organ development regulation, cell proliferation and cell cycle regulation in insects. Notch gene locus mutation can lead to embryonic death and wing loss in Drosophila. The expression of intracellular domain of Notch (NICD) can affect the development of follicular cells in the ovary of Drosophila, cockroaches and other insects. Delta mediates the formation of body segments and the normal development of nervous system in insects. Su(H) mainly affects the cell cycle process of insect cells in the form of transcription factors. Fringe plays a key role in the development of wings of such insects as Drosophila and Bombyx mori. In addition, Notch signaling pathway interacts with Hippo signaling pathway, Wnt signaling pathway and EGFR signaling pathway, indicating that Notch signaling pathway is not a single line form but a complex network structure involved in insect life process. In recent years, the research on Notch signaling pathway has been extended from insects to major human diseases, oncology medicine and molecular therapy. In view of the highly conservative nature of Notch signaling pathway, the research results of Notch signaling pathway in insects not only play a key role in exploring the developmental mechanism of insects, but also provide important references and new ideas for studying other animals and even human diseases.
    Research progress of insect miRNAs
    YANG Jie, XIE Miao, XU Xue-Jiao, BAI Jian-Lin, YOU Min-Sheng
    2021, 64( 2):  259-280.  doi:10.16380/j.kcxb.2021.02.013
    Abstract ( 396 )   PDF (2714KB) ( 173 )   PDF(mobile) (2714KB) ( 19 )     
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     MicroRNAs (miRNAs) are a class of 19-24 nt endogenous non-coding small RNAs universally existing in various organisms. MiRNAs can regulate gene expression mainly by the combination between its seed region and the ORF or 3′UTR of target genes at the posttranscriptional level, and play critical roles in multiple biological processes including cell differentiation, proliferation and apoptosis. As miRNAs have eventually become a research hotspot in life sciences, great advances have been made in the study of insect miRNAs. The development of highthroughput sequencing and bioinformatics have accelerated the identification of miRNAs in different species, providing the theoretical basis for subsequent research. MiRNAs can be identified with direct cloning, bioinformatics prediction and highthroughput sequencing while their expression levels can be detected through miRNA gene chip analysis, Northern blot and realtime quantitative PCR (RT-qPCR). Inhibition of expression or overexpression of miRNAs can be applied to further reveal their biological functions. MiRNAs exert significant influence on insect growth and reproduction process by participating in ecdysone pathway and regulating the expression of some related genes such as genes related to ecdysone receptor, sex differentiation, wing development, lipid metabolism and ovarian development. MiRNAs are also involved in the circadian rhythm, memory formation and leaning capacity of some insects. In the progress of insect-virus interaction, a number of virus-encoded miRNAs disturb the immune response of host insects by regulating target gene expression while the insectencoded miRNAs influence virus replication. MiRNAs have also been found to participate in insect immune response against exogenous pathogens via regulating the expression of immunerelated genes, which affect innate immune response of insects. Additionally, it has been reported that miRNAs develop or enhance insecticide resistance by negatively regulating the expression of detoxification-related genes, altering insect susceptibility to insecticides and contributing to insecticide resistance in insects. This review provides a theoretical basis for further understanding of insect miRNAs and their potential applications in integrated pest management.
    CONTENTS
    Contents of Vol. 64 Issue 2
    2021, 64( 2):  281-281. 
    Abstract ( 97 )   PDF (484KB) ( 19 )     
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