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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 May 2019, Volume 62 Issue 5
For Selected: View Abstracts Toggle Thumbnails
  • RESEARCH PAPERS
    Regulation of ATG8 subcellular localization and nuclear shrinkage by 20-hydroxyecdysone in the fat body of Bombyx mori
    ZHANG Shu-Yao, DAI Yi-Chen, WU Kun-Zhong, LI Shu-Yan, CAO Yang, DENG Xiao-Juan, TIAN Ling
    2019, 62(5):  527-534.  doi:10.16380/j.kcxb.2019.05.001
    Abstract ( 539 )   PDF (15407KB) ( 165 )     
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    【Aim】 The fat body is the major site for metabolism and innate immunity in insects. ATG8 protein subcellular localization is one of the key biomarkers for autophagy, and nuclear shrinkage is one morphological characteristic of apoptosis. However, there is a lack of cellular observation of BmATG8 protein during molting and metamorphosis of Bombyx mori. This work aims to determine the spatiotemporal changes in BmATG8 subcellular localization and nuclear morphology in the fat body of B. mori and to explore their regulation by 20-hydroxyecdysone (20E). 【Methods】 By using immunofluorescent staining and Hoechst staining, the changes in BmATG8 localization and nuclear morphology in the fat body of B. mori during day 2 of the 4th instar larva to day 2 of the prepupa, after injection of 20E (10 μg/larva) in the fat body of the day 2 5th instar larvae, and in larvae at the wandering stage after RNAi of 20E receptor gene usp were detected, respectively. 【Results】 During larval molting and larval-pupal metamorphosis of B. mori, BmATG8 protein was highly expressed in the fat body, and meanwhile nuclear shrinkage occurred. The 20E treatment (10 μg/larva) induced BmATG8 expression and its cytoplastic localization as well as nuclear shrinkage at the normal feeding larval stage. RNAi of usp in B. mori larva at the wandering stage decreased the content of cytoplastic BmATG8 and alleviated the nuclear shrinkage in fat body. 【Conclusion】 BmATG8 not only exists in the cytosol of B. mori during the larval-pupal metamorphosis, but also is highly expressed at the larval molting stage, occurring simultaneously with the nuclear shrinkage. Moreover, cytoplastic localization of BmATG8 and nuclear shrinkage are regulated by 20E signaling. This study provides a foundation for further studying the function and regulatory mechanism of BmATG8 in the future.
    Cloning of two clip-domain serine protease genes and their expression in response to exogenous hormone and immune challenge in Lasioderma serricorne (Coleoptera: Anobiidae)(In English)
    CHEN Chun-Xu, XU Kang-Kang, YANG Hong, ZHAO Feng, YAN Yi, HU Da-Ming, YANG Wen-Jia
    2019, 62(5):  535-546.  doi:10.16380/j.kcxb.2019.05.002
    Abstract ( 580 )   PDF (2524KB) ( 106 )     
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    【Aim】 As essential components of extracellular signaling cascades, clip-domain serine proteases (CLIPs) play important roles in insect development and innate immunity. This study aims to clone two CLIP genes from the cigarette beetle, Lasioderma serricorne, to clarify their developmental stage- and tissue-specific expression profiles, and to analyze their expression changes in response to exogenous hormone 20-hydroxyecdysone (20E) and immune challenge, so as to lay the foundation for further understanding the physiological functions of CLIPs in L. serricorne. 【Methods】 The full-length cDNAs of two CLIP-encoding genes (LsCLIP1 and LsCLIP2) were cloned using RT-PCR, and the deduced protein structure was predicted using different bioinformatics software, and the phylogenetic tree of insect CLIPs was constructed using the MEGA 6.06 program. The mRNA expression profiles of these two genes in different developmental stages [early larva (<24 h post egg hatching), late larva (older than the 4th instar), pupa (>48 h post pupation), early adult (<24 h post eclosion), and late adult (7 d post eclosion)] and different tissues (cuticle, fat body, gut, and carcass) of the 5th instar larvae, and the 4th instar larvae of L. serricorne injected with 20E (120 ng/larva) and peptidoglycan (0.2 μL) from Escherichia coli or Staphylococcus aureus were detected by quantitative real-time PCR (qPCR). 【Results】 The full-length cDNA sequences of LsCLIP1 and LsCLIP2 were cloned from L. serricorne, and both genes have an open reading frame of 1 194 bp encoding 397 amino acid residues. The predicted CLIP1 and CLIP2 proteins both contain a typical clip domain and a trypsin-like serine protease domain. Phylogenetic analyses revealed that CLIP1 and CLIP2 belong to subfamily C CLIPs. The qPCR analyses confirmed that both LsCLIP1 and LsCLIP2 were expressed throughout the developmental stages and in all the assayed larval tissues of L. serricorne, with particularly high expression level in the pupal stage and the cuticle, respectively. Expression of both genes was significantly upregulated in larvae exposed to 20E and following challenge with peptidoglycan from E. coli or S. aureus. 【Conclusion】 It is suggested that LsCLIP1 and LsCLIP2 might be involved in insect molting and innate immune response. These results provide valuable information for further study on the regulation of CLIPs in insects.

    Analysis of the transcriptome and chemoreception-related genes of Agrilus zanthoxylumi (Coleoptera: Buprestidae)
    YANG Ping, XIE Shou-An, GONG Xue-Fang, CHE Xian-Rong, WANG Yan-Lai, LÜ Shu-Jie
    2019, 62(5):  547-560.  doi:10.16380/j.kcxb.2019.05.003
    Abstract ( 559 )   PDF (5511KB) ( 146 )     
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    【Aim】 To establish the transcriptome database of the Agrilus zanthoxylumi, and to obtain its genomic data. 【Methods】 The transcriptome of the different tissues (antennae, head, thorax, abdomen, leg, wing) of A. zanthoxylumi adults was sequenced using an Illumina NovaSeq 6000 platform, and the unigene sequences were compared with the homologous sequences in public databases by BLAST. Chemoreception-related genes were screened out by BLAST homology search, and their nucleotide sequences were compared with those of other reported chemoreception-related genes of Coleoptera insects for phylogenetic analysis. The expression levels of these genes in different tissues of A.zanthoxylumi adults were analyzed based on the RPKM value. 【Results】 After sequencing and sequence splicing, a total of 80 320 genes and 169 398 contigs were obtained. The G+C proportions of contigs and unigenes were 37.63% and 39.18%, respectively, and the average length of contigs and the average length of unigenes were 1 084.33 and 828.75 bp, respectively. There were 37 374 unigenes with a length distribution mainly in 200-400 bp, accounting for 46.53% of the total unigenes. Origin species distribution of similar genes with unigenes of A. zanthoxylumi annotated in the NR database was Tribolium castaneum (26.80%), Mus musculus (13.87%), Oryctes borbonicus (5.26%), Dendroctonus ponderosae (4.10%), Lasius niger (2.36%), and other species (47.61%). There were 27 488 unigenes aligned to the GO database, which can be divided into three functional categories including molecular function, cellular component and biological process in a total of 59 processes. According to the gene annotation against the  KOG database, these unigenes can be divided into 25 categories. The most annotated functional category was the common function (4 666 unigenes), while the least annotated was cell movement-related (only 40 unigenes). When 80 320 unigenes were mapped to the KEGG database, 21 104 unigenes were grouped into 35 metabolic pathways, accounting for 26.27% of the total. The most annotated metabolic pathway was the transcription pathway (2 037 unigenes). By gene annotation against the NR database, we found eight odorant receptor (OR) genes, seven ionotropic receptor (IR) genes and six gustatory receptor (GR) genes. Tissue expression profiles showed that the three kinds of chemoreception-related genes (OR, IR and GR genes) had significantly higher expression levels in the antennae than in other tissues of adults, and the expression level of AzanOR1 in the antennae showed the most significant difference between female and male, while the expression levels of the three kinds of chemoreception-related genes in the legs of adults showed no difference between female and male. 【Conclusion】 This study obtained the transcriptome data of A. zanthoxylumi. The results provide a molecular foundation for further studying the gene function in A. zanthoxylumi.
    Construction of an electroporation-mediated microinjection platform and its application in transient overexpression of genes in Anopheles sinensis (Diptera: Culicidae)
    CHE Lin-Rong, HE Zheng-Bo, HAN Bao-Zhu, CHEN Xiao-Jie, YAN Zhen-Tian, QIAO Liang, CHEN Bin
    2019, 62(5):  561-571.  doi:10.16380/j.kcxb.2019.05.004
    Abstract ( 487 )   PDF (10762KB) ( 151 )     
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    【Aim】 To construct the electroporation-mediated microinjection platform for Anopheles sinensis and to accomplish the transient overexpression of genes in vivo with the platform for its verification, so as to lay a foundation for the systematic analysis of gene function. 【Methods】 We constructed an electroporation-mediated microinjection platform for An. sinensis using CUY21EDITII electroporator as the main body. The individuals of An. sinensis at 3 h after pupation were injected with transiently overexpressed plasmids containing EGFP and Bm-iAANAT constructed by using in-fusion cloning, and then subjected to electronic shock. The cuticle pigmentation and fluorescence of surviving individuals at 39 h after pupation were observed under stereofluorescence microscopy. The expression levels of EGFP and Bm-iAANAT were detected by qRT-PCR. 【Results】 Overexpression plasmids PIZ-modi-Aepub-EGFP-SV40 and PIZ-modi-Aepub-AANAT-T2A-EGFP-SV40 were constructed and used for microinjection. After injection with PIZ-modi-Aepub-EGFP-SV40 and electric shock, the percentage of surviving melanized pupae of An. sinensis reached 87.5% at 39 h after pupation, of which 92.7% individuals were significantly blocked from melanization and showed obvious green fluorescence compared with the individuals injected with PIZ-modi-EGFP-SV40 without promoter in the negative control group and those injected with overexpression plasmid PIZ-modi-Aepub-EGFP-SV40 without electric shock in the positive control group. In addition, EGFP gene was apparently overexpressed in the fluorescent individuals of the treatment group. The survival rate of individuals after injection with PIZ-modi-Aepub-AANAT-T2A-EGFP-SV40 was up to 80.4% at 39 h after pupation, of which 92.2% individuals were significantly blocked from melanization and appeared obvious green fluorescence compared with the individuals injected with PIZ-modi-AANAT-T2A-EGFP-SV40 without promoter in the negative control group and those injected with overexpression plasmid PIZ-modi-Aepub-AANAT-T2A-EGFP-SV40 without electric shock in the positive control group. Furthermore, the expression levels of Bm-iAANAT and EGFP genes were evidently enhanced in these individuals as well. 【Conclusion】 We successfully constructed the electroporation-mediated microinjection platform for A. sinensis, with which we accomplished the transient overexpression of reporter genes in live pupae conveniently, rapidly and efficiently and produced the target phenotypes, laying a foundation for the functional genome research in A. sinensis.
    Construction of a yeast two-hybrid library for membrane proteins of Apis cerana cerana (Hymenoptera: Apidae) larvae
    SUN Li, YUE Jin-Jin, FEI Dong-Liang, LI Ming, MA Ming-Xiao, SONG Ming-Xin
    2019, 62(5):  572-577.  doi:10.16380/j.kcxb.2019.05.005
    Abstract ( 379 )   PDF (2200KB) ( 257 )     
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    【Aim】 This study aims to construct the yeast two-hybrid cDNA library for membrane proteins of Apis cerana cerana larvae by cloning the larval membrane protein cDNA into pPR3-N using FullCoV technique. 【Methods】 The total RNA was extracted from the 2-3 day-old worker larvae of A. cerana cerana. After mRNA was isolated, the first strand cDNA of membrane protein was synthesized by reverse transcriptase, and then the double-stranded cDNA was synthesized. After being added to the 5′ end of the double-stranded cDNA, the linker with the recombinant sequence was ligated with the vector pPR3-N by FullCoV technology. The ligation product was electrotransformed into DH10B competent cells to construct the larval membrane protein cDNA library, and the titer of the library and the size of the inserted cDNA fragment were examined and verified. 【Results】 A yeast two-hybrid cDNA library for membrane proteins of A. cerana cerana larvae was successfully constructed by the FullCoV technique. The library had the capacity of 1.5×107 cfu, the titer of 3×106 cfu/mL, and the recombination rate of 100%. 【Conclusion】 In this study the yeast two-hybrid cDNA library for membrane proteins of A. cerana cerana larvae was successfully constructed using FullCoV technique, which is helpful for the further study on the interaction between pathogen infecting A. cerana cerana and host proteins.
    Accumulation and metabolism of polyunsaturated fatty acids from food in Musca domestica larvae and the effects on their growth
    YANG Yang, LUO Kun, JIANG Chao, WU Jian-Wei, ZHU Gui-Ming
    2019, 62(5):  578-585.  doi:10.16380/j.kcxb.2019.05.006
    Abstract ( 584 )   PDF (1523KB) ( 106 )     
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    【Aim】 To clarify the accumulation and metabolic transformation of various polyunsaturated fatty acids in food by Musca domestica larvae, and to explore the effects of various polyunsaturated fatty acids on the growth of M. domestica larvae. 【Methods】 Different concentrations (3%, 6% and 12%) of polyunsaturated fatty acids (linoleic acid, alpha-linolenic acid, arachidonic acid and docosahexaenoic acid) were added to the basic diet to feed the M. domestica larvae which had been defatted and subcultured for generations, the total fatty acids of M. domestica larvae fed on the feed were extracted, detected and analyzed by gas chromatography, and the body weight of the larvae was detected to assess the effects of polyunsaturated fatty acids on the growth of M. domestia larvae. 【Results】 Linoleic acid, alpha-linolenic acid and arachidonic acid were enriched in M. domestica larvae, and their enrichment degree increased with the increase of the concentration of polyunsaturated fatty acids in food. The highest concentrations (the proportion in total fatty acids) of linoleic acid, alpha-linolenic acid and arachidonic acid enriched in larvae were 21.93%, 16.13% and 9.68%, respectively, while docosahexaenoic acid could not be enriched in M. domestica larvae, suggesting that polyunsaturated fatty acids added to the larvae of M. domestica have been metabolized without production of new fatty acids in their bodies, while docosahexaenoic acid from food is eliminated after catabolism. The body weight of M. domestica larvae was significantly increased after feeding on diets containing alpha-linolenic acid and arachidonic acid. The larval weight in the 6% alpha-linolenic acid added group was significantly higher than that in the control group (larvae feeding on defatted culture) and 3% and 12% alpha-linolenic acid added groups, and the larval weight in the 3% and 6% arachidonic acid added groups was significantly higher than that in the control group and 12% arachidonic acid added group. 【Conclusion】 M. domestica larvae can enrich some polyunsaturated fatty acids from food. The longer the carbon chain of polyunsaturated fatty acids, the lower the degree of enrichment of polyunsaturated fatty acids until they can not be enriched. The enriched polyunsaturated fatty acids have influences on the growth of M. domestica larvae in different degrees.
    Effects of exogenous trehalose on the survival and cold hardiness of adult Dastarcus helophoroides (Coleoptera: Bothrideridae)
    LUO Li-Ping, WANG Xiao-Yi, TANG Yan-Long, HU Shuai, YANG Zhong-Qi, ZHAO Jian-Xing
    2019, 62(5):  586-593.  doi:10.16380/j.kcxb.2019.05.007
    Abstract ( 537 )   PDF (1520KB) ( 106 )     
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    【Aim】 This study aims to evaluate the influence of feeding different concentrations of exogenous trehalose on the survival and cold hardiness of adult Dastarcus helophoroides, an important and most effective natural enemy of longhorned beetles. 【Methods】 D. helophoroides adults were fed on a semi-artificial diets containing 3%, 6% and 9% trehalose, respectively, in the laboratory, and those fed on the semi-artificial diet without trehalose were used as the control group. After 10 weeks, the survival rate of adults was calculated. In addition, the supercooling point and water content of adults not subjected to low temperature treatment and subjected to low temperature treatment (10℃ for 3 d) were measured. 【Results】 The survival rate of D. helophoroides adults fed on the semi-artificial diets containing 6% trehalose was the highest (86.67%) among all the treatments. Whether subjected to low temperature treatment or not, D. helophoroides adults fed on the semi-artificial diet containing 9% trehalose had the lowest supercooling point as compared to those fed on the semi-artificial diet containing 3% and 6% trehalose and without trehalose (the control): the supercooling point of adults unsubjected to low temperature was -19.30℃, while that of adults subjected to low temperature treatment was -21.60℃. Low temperature treatment had a significant effect on the water content of adults fed on the diet without trehalose but no significant effect on the water content of adults fed on the semi-artificial diet containing trehalose. 【Conclusion】 Exogenous trehalose has significant influence on the survival and cold hardiness of D. helophoroides adults. Thus exogenous trehalose can be utilized to improve the survival rate and cold hardiness of D. helophoroides adults in laboratory rearing.
    Olfactory and behavioral responses of Solenopsis invicta (Hymenoptera: Formicidae) workers to cotton volatiles induced by cotton aphids
    LI Jun-Long, CHEN Li, LIU Chang-Ming
    2019, 62(5):  594-601.  doi:10.16380/j.kcxb.2019.05.008
    Abstract ( 631 )   PDF (1501KB) ( 149 )     
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    【Aim】 There is a facultative mutualistic interaction between the red imported fire ant, Solenopsis invicta and the cotton aphid, Aphis gossypii. Fire ants may utilize cotton aphid-induced cotton volatiles to locate mutualistic partners. This study aims to test the olfactory and behavioral responses of S. invicta workers to cotton volatiles induced by cotton aphid. 【Methods】 The behavioral response of S. invicta workers to cotton odor was tested by Y-tube. The electroantennogram (EAG) responses of the fire ant workers to nine volatile compounds including (1S)-(-)-α-pinene, (1S)-(-)-β-pinene, β-caryophyllene, (E, E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT), (E)-4,8-dimethyl 1,3,7-nonatriene (DMNT), octanal, 6-methyl-5-hepten-2-one, (Z)-(3)-hexenyl acetate, and methyl salicylate at different dosages (100, 10, 1 and 0.1 μg) were tested using fire ant alarm pheromone 2-ethyl-3,5(6)-dimethylpyrazine as the positive control, and the influence of the volatile compounds on the behavior choice of the fire ant workers was tested by Y-tube olfactometer. 【Results】 The results showed that fire ant workers were significantly attracted to the cotton plants damaged by cotton aphids over undamaged ones. The EAG responses of fire ant workers to the nine volatile compounds were dose-dependent. These compounds triggered the highest EAG response in fire ant workers at the dose of 100 μg, and methyl salicylate and 6-methyl-5-hepten-2-one caused the greatest EAG responses. In behavioral selection experiments, fire ant workers were significantly attracted to methyl salicylate, 6-methyl-5-hepten-2-one and DMNT. 【Conclusion】 Among cotton aphid-induced volatile compounds, methyl salicylate and 6-methyl-5-hepten-2-one significantly attract fire ants, and they may play a key role in locating cotton aphids by fire ants for establishment of mutualistic interaction.
    Bioefficacy of the combined application of entomopathogenic nematode Heterorhabditis beicherriana strain LF and Bacillus thuringiensis strain HBF-18 against Holotrichia oblita (Coleoptera: Scarabaeidae) larvae
    LI Er-Tao, CAO Ya-Zhong, ZHANG Shuai, LI Ke-Bin, LI Jian-Yi, WANG Qing-Lei, LIU Chun-Qin, YIN Jiao
    2019, 62(5):  602-614.  doi:10.16380/j.kcxb.2019.05.009
    Abstract ( 412 )   PDF (1992KB) ( 70 )     
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    【Aim】 This study aims to assess the possible synergistic effect of combined application of the entomopathogenic nematode Heterorhabditis beicherriana strain LF (LF) and Bacillus thuringiensis strain HBF-18 (Bt HBF-18) based on their pathogenicity to Holotrichia oblita larvae, so as to develop a new alternative method for white grub control. 【Methods】 The pathogenicity of LF at different doses to the 7-10-day-old larvae of H. oblita were investigated at different temperatures and soil moistures in the laboratory. The effects of Bt HBF-18 on the survival of LF, and the bioefficacy of the combined application of nematodes and Bt against the 7-10-day-old larvae of H. oblita were also investigated in the laboratory. At the same time, the bioefficacy of the combined application of LF and Bt HBF-18 against the 7-10-day-old larvae of H. oblita was investigated with outdoor pot experiments. 【Results】 The results showed that the larval mortality of H. oblita increased with the increase of the application dosage of LF and the treatment duration, with the larval mortality rate reaching 100% at 7 d after treatment with LF at the dosage of 800 IJs/100 μL and above. Moreover, 25℃ temperature and 14%-20% soil moisture were proved to be the ideal conditions for the best infection efficiency of LF, and too low or too high humidity significantly affected its infection efficiency. Laboratory bioassays showed that the LC50 of Bt HBF-18 against H. oblita larvae after treatment for 9 d was 1.44×108 CFU/g soil, and at this concentration Bt HBF-18 showed little effect on the survival of LF. In addition, both the indoor bioassay and outdoor pot experiment revealed that the combined application of LF and Bt HBF-18 could significantly improve their bioefficacy against H. oblita larvae, showing additive or synergistic effect. Indoor bioassay showed that the larval mortality rates in the treatment with LC50Bt+200 IJs/100 μL LF for 3 d were increased by about 43.07% and 36.05%, respectively, as compared with that in LF or Bt HBF-18 applied alone, indicating that the combined application of LF and Bt HBF-18 has significant synergistic effect against H. oblita larvae. Treatments with 1/2 LC50Bt+1 000 IJs/mL LF, LC50Bt+1 000 IJs/mL LF and 1/2 LC50Bt+1 500 IJs/mL LF in the outdoor pot experiment showed synergistic effect against H. oblita larvae, and 1/2 LC50Bt+1 500 IJs/mL LF showed the best effect, with the mortality of H. oblita larvae increased by about 38.89% and 80.55%, respectively, as compared with that in LF or Bt HBF-18 applied alone. 【Conclusion】 Overall, the interaction between the entomopathogenic nematode LF and Bt HBF-18 against the larvae of H. oblita is either additive or synergistic.
    A survey method based on mobile terminal for rice planthoppers in paddy fields
    YU Pei-Shi, GUO Long-Jun, YAO Qing, YANG Bao-Jun, TANG Jian, XU Wei-Gen, CHEN Yu-Yang, ZHU Xu-Hua, CHEN Hong-Ming, ZHANG Chen-Guang, DUAN De-Kang, BEI Wen-Yong, PENG Qing-Hui
    2019, 62(5):  615-623.  doi:10.16380/j.kcxb.2019.05.010
    Abstract ( 535 )   PDF (10030KB) ( 85 )     
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    【Aim】 This study aims to design and develop a survey method based on mobile terminal for rice planthoppers in paddy fields, so as to reduce the labor intensity, improve the objectivity of rice planthopper survey in paddy fields and trace the survey results of rice planthoppers. 【Methods】 An image acquisition device for rice planthoppers in paddy fields was developed by an Android camera, a handheld extendable pole and an Android mobile phone loaded with camera APP. In the Android development environment, the video capture and encoding module, the video transport module and the camera controlling module of the Android camera were developed by the socket communication and video coding technologies. The video preview module, the mobile controlling module and the image uploading module on the mobile phone were developed by the Android NDK and Java web technologies. The video in the camera was compressed into H.264 format file in real time, which was transmitted to the mobile phone by the RTSP/RTP protocol. The phone can preview the video captured by the camera by decompression, control the camera to capture the rice planthopper images, and simultaneously transmit the images to the mobile phone. The automatic identification algorithm for rice planthoppers was deployed in the cloud server. The clients can select the rice planthopper images to upload to the cloud server. The identification results would be returned to the mobile phone after running the identification algorithm in the server. 【Results】 By using the survey method based on the mobile terminal for rice planthoppers in paddy fields, the mobile phone can preview the video of rice planthoppers at the base of rice stem captured by the camera in real time and control the camera to take pictures. The automatic identification algorithm for rice planthoppers in the cloud server can identify both the rice planthoppers in the image and their developmental stages, with the average detection rates of 86.9% and 81.7%, and the false alarm rates of 11.2% and 16.6%, respectively. 【Conclusion】 The survey method based on the mobile terminal for rice planthoppers can easily collect the images of rice planthoppers at the base of rice plants, and quickly identify and count the number of rice planthoppers in different developmental stages. This method can not only reduce the labor of forecasting technicians, but also avoid the survey subjectivity of rice planthoppers in paddy fields and realize the traceability of rice planthopper survey.
    Spatiotemporal dynamics of genetic variation in populations of the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), in China
    KE Fu-Shi, YOU Shi-Jun, HUANG Su-Mei, LIU Tian-Sheng, XIE Dan-Dan, YOU Min-Sheng
    2019, 62(5):  624-633.  doi:10.16380/j.kcxb.2019.05.011
    Abstract ( 398 )   PDF (1824KB) ( 99 )     
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     【Aim】 The diamondback moth, Plutella xylostella L., is one of the most important dispersal pests of cruciferous vegetables worldwide, and it is featured by the interrelated metapopulations of “source-sink” between overwintering regions (OR) and seasonally breeding regions (SBR) in China. This study aims to investigate the spatiotemporal dynamics of genetic variation in P. xylostella populations in China and to further uncover the effect of dispersal behavior on its regional outbreaks. 【Methods】 The genetic variation of P. xylostella populations was investigated based on four independent datasets of 1 567 COI sequences of P. xylostella at different sampling time in China. Each dataset was classified into three groups, i.e., OR populations, SBR populations and populations sampled at a given sampling time (ST). The genetic diversity, genetic differentiation, haplotype similarity and demography history of these populations were investigated. 【Results】 Genetic variation analysis of P. xylostella populations based on COI sequences revealed a comparable genetic variation between OR and SBR populations sampled at the same time. Although the unstable haplotype frequency in SBR led to a great genetic differentiation of SBR-involved populations, COI haplotypes in SBR populations either could be found in OR populations sampled at the same time or showed a limited difference (<2 bp) from the COI haplotypes in OR populations. The haplotype frequency of SBR populations varied greatly among different years. Variation of genetic differentiation between SBR populations was the highest in all population combinations, while that between ST populations was the lowest. Haplotype analysis at different sampling time showed a similar pattern in nucleotide mismatch distributions, and the similar haplotype pattern consists of several dominant haplotypes. 【Conclusion】 Our results indicate that dispersal is the major factor in shaping the genetic variation of SBR populations of P. xylostlla, and P. xylostella populations tend to exhibit a temporal stability and interrelation of genetic variation in different regions of China. The nature of metapopulation provides an important ecological base for understanding the seasonal dispersal of P. xylostella.
    Taxonomy of Holcoderus from China, with description of a new species (Coleoptera: Carabidae: Lebiini)
    LIU Yi-Zhou, SHI Hong-Liang, LIANG Hong-Bin
    2019, 62(5):  634-644.  doi:10.16380/j.kcxb.2019.05.012
    Abstract ( 785 )   PDF (23028KB) ( 170 )     
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    【Aim】 The genus Holcoderus Chaudoir belongs to the order Coleoptera, family Carabidae, tribe Lebiini. This study aims to revise the taxonomy of every species of the genus in China. 【Methods】 Based on the collections of Institute of Zoology, Chinese Academy of Sciences and the types deposited in European museums, specimens were observed by using morphology comparative methods. 【Results】 Total five species of the genus Holcoderus are recognized in China, including one new species (Holcoderus bisetus sp. n., type locality: Xishuangbanna, Yunnan), and three newly recorded species (H. gracilis, H. smaragdinus and H. aeripennis). Morphological descriptions, photographs of habitus and aedeagus for each species are provided, and a key to Chinese species is compiled. 【Conclusion】 To date, the species number of the genus Holcoderus found in China have increased from one to five. 
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    Effects of light intensity on the growth, development and reproduction of Megacopta cribraria (Hemiptera: Plataspidae)
    XU Zhe, CUI Juan, BI Rui, GAO Yu, SHI Shu-Sen
    2019, 62(5):  645-652.  doi:10.16380/j.kcxb.2019.05.013
    Abstract ( 519 )   PDF (1531KB) ( 121 )     
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    【Aim】 To clarify the effects of light intensity on the growth, development and fecundity of Megacopta cribraria and to further explore its adaptation to light environment. 【Methods】 Under the conditions of temperature 24±1℃, relative humidity 60%±10% and photoperiod 16L∶8D, the growth, development and reproduction indexes of M. cribraria on soybean host plant, including developmental duration of each developmental stage, adult longevity, survival rate, nutrient accumulation efficiency of the nymphal stage, under different light intensities (500, 2 500, 4 500, 6 500, 8 500 and 10 500 lx) were determined, and the effects of light intensity on population trend changes were further analyzed by using life table method. 【Results】 Light intensity had significant effects on the duration of various developmental stages, survival rate and adult fecundity of M. cribraria. The developmental duration of each developmental stage had a tendency to shorten with the increase of light intensity. The developmental rate of each developmental stage and the nutrient accumulation efficiency of the nymphal stage were significantly positively correlated with light intensity. The relationships between the developmental rate of each developmental stage and light intensity were as follows: V1=0.129968exp(0.011310LI) (egg stage, R2=0.610, P<0.0001),  V2=0.000767LI+0.014182 (nymphal stage, R2=0.980, P<0.0001), and V3=0.019000LI0.418000(preoviposition period of female, R2=0.837, P<0.0001). The nutrient accumulation efficiency of nymphal stage and light intensity fitted the cubic function model y=0.0004x3-0.0064x2+0.0361x+0.0660 (R2=0.983, P<0.0001). The population trend index I increased significantly with the increase of light intensity. The M. cribraria population could not complete the reproductive process when the light intensity was lower than 2 500 lx. 【Conclusion】 Light intensity significantly affects the growth and fecundity of M. cribraria. Higher light intensity (10 500 lx) is more conducive to its population growth, while lower light intensity (≤2 500 lx) will lead to gradual extinction of the population.
    CONTENTS
    Contents of Vol. 62 Issue 5
    2019, 62(5):  653-653.  doi:10.16380/j.kcxb.2019.05.014
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