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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 July 2020, Volume 63 Issue 7
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    Cloning and expression profiling of the serine protease inhibitor gene Nlserpin4 in the brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae)
    WANG Zheng-Liang, ZHU Hang-Feng, PAN Hai-Bo, YU Xiao-Ping
    2020, 63(7):  779-787.  doi:10.16380/j.kcxb.2020.07.001
    Abstract ( 574 )   PDF (3066KB) ( 383 )   PDF(mobile) (3066KB) ( 30 )     
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    【Aim】 To clone and characterize the serine protease inhibitor gene Nlserpin4 from the brown planthopper (BPH), Nilaparvata lugens, and to determine its spatio-temporal expression profiles and its expression pattern induced by entomopathogenic fungi. 【Methods】 Based on the transcriptome and whole genome data of BPH, the full-length cDNA of Nlserpin4 from BPH was cloned by PCR, and its nucleotide and protein sequences were subsequently characterized using bioinformatics tools. The expression patterns of Nlserpin4 across different developmental stages (egg, 1st-5th instar nymphs and newly emerged female and male adults), in different tissues (fat body, gut, hemolymph and carcass) of the 5th instar nymphs, and in the 5th instar nymphs at different time post injection of the entomopathogenic fungus Metarhizium anisopliae were determined by qRT-PCR. 【Results】 The full-length cDNA of Nlserpin4 (GenBank accession no.: MN822802) was successfully cloned from BPH. The open reading frame (ORF) of Nlserpin4 is 1 227 bp in length, encoding 408 amino acids with the predicted molecular weight of 45.91 kD and isoelectric point (pI) of 6.23. The amino acid sequence analysis revealed that Nlserpin4 protein has no putative N-glycosylation site, but contains a predicted signal peptide consisting of 23 amino acid residues at the N-terminal region and a typical RCL region of the serpin family at the C-terminal region with an active cleavage site which can be recognized by target protease. The phylogenetic analysis showed that Nlserpin4 is closely related to the serpins of other hemipteran insects, with the highest homology with Sipha flava serpin4. The qRT-PCR results showed that the expression of Nlsperpin4 had obvious temporospatial characteristics. The expression level of Nlsperpin4 in adults was significantly higher than those in other developmental stages, and the highest expression level was observed in male adult. Nlsperpin4 was expressed in the fat body, gut, haemolymph and carcass, with the highest expression level in the carcass of the 5th instar nymphs. The expression of Nlserpin4 in BPH was significantly down-regulated after infection with M. anisopliae within 48 h post injection, but the expression level of Nlserpin4 was gradually increased with the increase of infection time. 【Conclusion】 The Nlserpin4 of BPH is differentially expressed in different developmental stages, different tissues and different time after infection with the entomopathogenic fungus M. anisopliae. The results of this study provide a theoretical basis for further studying the functions of Nlserpin4 in the growth, development and immune regulation of BPH.
    Identification and expression profiling of cuticular protein genes in Galeruca daurica (Coleoptera: Chrysomelidae)
    DUAN Tian-Feng, LI Ling, MA Hong-Yue, PANG Bao-Ping, SHAN Yan-Min, ZHANG Zhuo-Ran
    2020, 63(7):  788-797.  doi:10.16380/j.kcxb.2020.07.002
    Abstract ( 453 )   PDF (2111KB) ( 109 )   PDF(mobile) (2111KB) ( 19 )     
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    【Aim】 Cuticular proteins, the main components of insect integument, play an important role in the development of insects. This study aims to identify cuticular protein genes from Galeruca daurica and to analyze their expression patterns, so as to lay a necessary foundation for investigation on their functions in the growth and development of G. daurica. 【Methods】 The complete open reading frame (ORF) sequences of cuticular protein genes were identified from G. daurica by bioinformatics methods according to the sequence information available in the transcriptome data assembled by our laboratory, and the expression profiles of the eight cuticular protein genes identified at different developmental stages and in different tissues (head, integument, digestive tract and fat body) of the 3rd instar larvae were detected by RT-qPCR. 【Results】 The complete ORF sequences of eight cuticular protein genes were identified from the transcriptome data of G. daurica, and named GdauCP1-8 (GenBank accession numbers: MN629000-MN629007). The ORFs of GdauCP1-8 are 417-810 bp in length, encoding eight proteins of 138-269 amino acids with the predicted molecular weight of 15-28 kD and pI of 4.45-8.62. The encoded proteins have signal peptides with 16-20 amino acids. GdauCP1 has a typical transmembrane domain, while the other seven GdauCPs do not have. Homologous sequence alignment and phylogenetic analysis showed that GdauCP3 has the highest amino acid sequence identity (60.00%) with Leptinotarsa decemlineata CP, while the other GdauCPs have the highest amino acid sequence identities (58.52%-80.00%) with Diabrotica virgifera virgifera CPs. GdauCP1-4 belong to the subfamily RR-2, GdauCP5-7 belong to the subfamily RR-1, and the subfamily identity of GdauCP8 was not defined. The RT-qPCR results showed that all of the eight GdauCP genes were significantly differentially expressed at different development stages and in different tissues of the 3rd instar larvae of G. daurica. GdauCP2, GdauCP4, GdauCP5 and GdauCP6 were highly expressed in the 1st instar larva, GdauCP3, GdauCP7 and GdauCP8 had high expression levels in the pupa, and GdauCP1 was highly expressed in the day-3 3rd instar larva. Except for the higher expression level of GdauCP2 in the adult, the other GdauCP genes had lower expression levels in the adult. GdauCP1 was highly expressed in the head and integument, and GdauCP2 and GdauCP8 had high expression levels in the fat body. GdauCP3, GdauCP4, GdauCP6 and GdauCP7 were highly expressed in the digestive tract, while GdauCP5 was highly expressed in the integument. 【Conclusion】 The expression levels of the eight GdauCP genes significantly differ in different developmental stages and larval tissues of G. daurica with different expression patterns, implying that different GdauCPs may have distinct functions.
    Inhibition of the activation of prophenol oxidase and the expression of antimicrobial peptide genes by the serine protease inhibitor Bmserpin2 in Bombyx mori
    LI Bing, SUN Fan, TAO Shan-Shan, XIA Jia-Feng, YE Chong-Jun
    2020, 63(7):  798-806.  doi:10.16380/j.kcxb.2020.07.003
    Abstract ( 450 )   PDF (4041KB) ( 73 )   PDF(mobile) (4041KB) ( 7 )     
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    【Aim】 Serine protease inhibitor family proteins are important protease inhibitors that regulate the autoimmune response in insects. This study aims to investigate the regulatory role of Bmserpin2 in two important autoimmune pathways, i.e., the prophenol oxidase (PPO) activation pathway and the TOLL pathway of antimicrobial peptides (AMPs) induced by gram-positive bacteria, in Bombyx mori. 【Methods】 Bmserpin2 gene fragment of B. mori was amplified by PCR, and the target protein expression was induced by prokaryotic expression system and purified by nickel column. The effect of Bmserpin2 on the activities of trypsin, chymotrypsin, elastase and protease K was determined after the reaction between the purified recombinant Bmserpin2 and the above proteases, respectively. The expression patterns of Bmserpin2 in the head, midgut, fat body, hemolymph, silk gland, and integument of the day-3 5th instar larvae of B. mori were detected by RT-qPCR. The recombinant Bmserpin2 was injected into the day-3 5th instar larvae of B. mori, and the effect of Bmserpin2 on the PPO activity in their hemolymphs was determined. After the day-3 5th instar larvae of B. mori was induced by Micrococcus luteus to produce antimicrobial peptides (AMP) and injected with Bmserpin2, the expression levels of AMP genes gloverin2 and moricin in their hemolymphs were detected by RT-qPCR. 【Results】 The recombinant plasmid was successfully constructed, and the target protein Bmserpin2 was expressed and purified. Bmserpin2 significantly inhibited the activities of trypsin and elastase, but had no significant effect on the activities of chymotrypsin and proteinase K, suggesting that Bmserpin2 has biological activity and catalytic specificity to different proteases. The expression levels of Bmserpin2 were the highest in the hemolymph and fat body of the 5th instar larvae of B. mori. Most importantly, Bmserpin2 was found to inhibit the PPO activity in the hemolymph of the 5th instar larvae of B. mori after injection of the recombinant Bmserpin2. AMP was produced in the 5th instar larvae of B. mori induced by M. luteus. The transcription levels of AMP genes gloverin2 and moricin in the hemolymph in the Bmserpin2 and M. luteus mixedly injected group was significantly down-regulated as compared with that in the M. luteus injected group. 【Conclusion】 Bmserpin2 may be involved in the immune pathway of the activation of PPO and the extracellular cascade reaction of TOLL pathway in B. mori.
    Tissue expression profiling and ligand binding characterization of the Plus-C odorant binding protein PsauOBP7 of Peridroma saucia(Lepidoptera: Noctuidae)
    SUN Ya-Lan, LV Qi-Hui, YANG Hai-Bo, HU Zhen-Jie, LI Ding-Xu, DONG Jun-Feng
    2020, 63(7):  807-816.  doi:10.16380/j.kcxb.2020.07.004
    Abstract ( 376 )   PDF (3927KB) ( 87 )   PDF(mobile) (3927KB) ( 18 )     
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    【Aim】 To clarify the expression profile of the Plus-C odorant binding protein PsauOBP7 in different chemosensory organs of the variegated cutworm, Peridroma saucia, and to analyze the odorant binding characteristics of the recombinant PsauOBP7. 【Methods】 The expression profile of PsauOBP7 in antennae, mouthparts, legs and wings of female and male moths of P. saucia was detected by qRT-PCR. The recombinant PsauOBP7 was expressed in prokaryotic expression system and purified. The expression profiles of PsauOBP7 in the head of different instar larvae and different adult tissues of P. saucia were analyzed by Western blot. The binding capabilities of the recombinant PsauOBP7 to 39 odor compounds were detected by fluorescence competitive binding assay. 【Results】 The recombinant PsauOBP7 was successfully expressed and purified. The qRT-PCR and Western blot assays showed that PsauOBP7 was expressed in the head of the 4th-6th instar larvae and the antennae, mouthparts, legs, and wings of female and male adults of P. saucia. The fluorescence competitive binding experiment showed that the binding ability of PsauOBP7 to (E)-2-hexenal was the strongest, with the Ki value of 1.4 μmol/L. In addition, PsauOBP7 had certain binding abilities to five ester compounds, dodecyl acetate, (Z)-3-hexenyl acetate, phenylethyl acetate, hexyl benzoate, and methyl cinnamate, with the Ki values of 5.7, 6.5, 8.9, 9.5, and 10.2 μmol/L, respectively. PsauOBP7 also had strong binding ability to two alcohols, (Z)-3-hexen-1-ol and farnesol, with the Ki values of 5.8 and 5.9 μmol/L, respectively. 【Conclusion】 The Plus-C odorant binding protein PsauOBP7 of P. saucia is expressed in various chemosensory organs of its larvae and adults, and can bind with a variety of plant odor compounds, suggesting that it plays an important role in searching for host plants of P. saucia.
    Discovery and characterization of an endogenous retroviral element, PxERV, in the genome of the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) 
    WANG Yue, LU Cong, LIU Tian-Sheng, CHEN Shao-Ping, YOU Min-Sheng
    2020, 63(7):  817-824.  doi:10.16380/j.kcxb.2020.07.005
    Abstract ( 424 )   PDF (2485KB) ( 79 )   PDF(mobile) (2485KB) ( 27 )     
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     【Aim】 Endogenous retroviruses (ERVs) are retrovirus-like elements that have been fixed in the host genome for generations. This study aims to characterize the sequence characteristics and infectious ability of an endogenous retroviral element, PxERV, in the diamondback moth (DBM), Plutella xylostella, which we found during an analysis of its testis transcriptome, so as to provide a basis for addressing the role of ERVs in P. xylostella. 【Methods】 The sequence and structural characteristics of PxERV in the P. xylostella genome were analyzed and identified using bioinformatics methods. The env gene sequence of PxERV was cloned and sequenced. A phylogenetic tree of amino acid sequences coded by env genes and envelope glycoproteins of nucleopolyhedroviruses of insects was constructed using MEGA6 software. The expression levels of env gene in the body and testis of strain G88 of P. xylostella at different developmental stages and the copy numbers of env gene in the adult of strain FZ and the adult and larva of strain G88 of P. xylostella were detected using qPCR technology. The independent replication activity of the PxERV in strain G88 was detected by using CRISPR/Cas9 to mediate the mutation of env gene. 【Results】 PxERV exhibits a structure of LTR-pol-env-LTR. The env gene of PxERV was evolutionarily related to the env genes of the retrotransposon osvaldo in Drosophila buzzatii and the endogenous retrovirus Ted in Trichoplusia ni. The expression level of env gene of PxERV was specifically high in male adult testis of strain G88, and its copy number was lower in strain FZ than in strain G88 and showed no difference among different developmental stages of strain G88. After multiple generations of self-crossing in strain G88, the mutant env gene was gradually reduced in the P. xylostella genome until the wild-type env gene was completely restored. 【Conclusion】 PxERV shows the independent replication activity between generations of P. xylostella, but no independent replication activity in different developmental stages of the same generation of P. xylostella. We assume that PxERV might complete inter-generational infection through the male reproductive system of P. xylostella, with further studies required to address the mechanism associated with its infection.
    Identification of proteins in the gut of Tsaitermes ampliceps (Isoptera: Rhinotermitidae)
    SU Li-Juan, WU Zhi-Wei, GAO Xin-Hao, ZHAO Peng-Fei, XIAO Yuan-Xi, CHU Jun-Peng, SONG An-Dong
    2020, 63(7):  825-834.  doi:10.16380/j.kcxb.2020.07.006
    Abstract ( 491 )   PDF (2943KB) ( 38 )   PDF(mobile) (2943KB) ( 5 )     
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    【Aim】 The aim of this study is to analyze and compare the composition and expression difference of proteins in the fore- and midgut and the hindgut including gut contents of Tsaitermes ampliceps workers, and then to excavate the enzymes and proteins that can degrade lignocellulose. 【Methods】 By two-dimensional electrophoresis of the proteins in the fore- and midgut and the hindgut including gut contents of T. ampliceps workers, 47 protein spots with high expression or high expression difference were sequenced by MALDI-TOF/MS and subjected to bioinformatics analysis. 【Results】 The sequence analysis showed that there are 13 structural proteins, 9 regulatory proteins, 10 termite metabolism-related proteins and 7 microbial metabolism-related proteins in the gut and gut content proteins of T. ampliceps. The PD Quest analysis showed that 11 proteins were highly expressed in both the fore- and midgut and the hindgut, 12 proteins mainly related to metabolism and belonging to regulatory proteins were expressed only in the fore- and midgut, and 8 proteins mainly related to microbial metabolism were expressed only in the hindgut. There are five enzymes involved in the degradation of lignocellulose in all the gut proteins, including endogenous cellulase secreted by termites themselves, endo-β-1,4-glucanase and peroxidase produced by bacteria, and GH11 produced by protozoans. 【Conclusion】 The degradation of lignocellulosic food is mainly in the fore- and midgut, and the further degradation of the degraded products and the metabolism of the products for microbial growth are mainly in the hindgut. The degraded products and bacterial proteins provide nutrients for anal feeding of termites.
    Effects of spore suspension concentration and host body size on the pathogenicity of Beauveria bassiana against Monochamus alternatus (Coleoptera: Cerambycidae) larvae
    GUO Han, LIU Zhu-Dong, SUN Jiang-Hua
    2020, 63(7):  835-842.  doi:10.16380/j.kcxb.2020.07.007
    Abstract ( 484 )   PDF (3366KB) ( 77 )   PDF(mobile) (3366KB) ( 14 )     
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    【Aim】 Beauveria bassiana is widely used in the biological control of insect pests. This study aims to investigate the effects of spore suspension concentration and host body size on the pathogenicity of B. bassiana against the Japanese pine sawyer, Monochamus alternatus, so as to provide basic information for practical biological control of M. alternatus using fungi B. bassiana. 【Methods】 After the 4th instar larvae of M. alternatus were inoculated with 0.5% Tween-80 (CK) and different concentrations (1×105, 1×106, 1×107, 1×108 and 1×109 conidia/mL) of B. bassiana spore suspension, respectively, the larval mortality and infection rate within 15 d post inoculation were assayed. Furthermore, after M. alternatus larvae in different body size (100-150, 200-220, 300-320, 400-420, 500-520 and 600-650 mg/individual) were inoculated with the optimal concentration (1×109 conidia/mL) of B. bassiana spore suspension, the larval mortality and infection rate within 20 d post inoculation were determined. 【Results】 After inoculation with 1×105-1×109 conidia/mL B. bassiana spore suspension, the 4th instar larvae of M. alternatus moved freely at the beginning, then they showed burned symptom on the head and their body color gradually turned red. Finally, the whole body was covered with hyphae. With the increase of spore concentration of B. bassiana, the corrected mortality and infection rate of the larvae increased significantly. When the 4th instar larvae were exposed to 1×106-1×109 conidia/mL B. bassiana spore suspension for 15 d, their accumulative corrected mortality rates in various treatments reached 100%. After the 4th instar larvae were inoculated with B. bassiana spore suspension at the concentrations of 1×107, 1×108 and 1×109 conidia/mL, the duration before death was the shortest. Similarly, at 15 d post inoculation, the corrected infection rates of the 4th instar larvae exposed to 0 (CK), 1×105, 1×106, 1×107, 1×108 and 1×109 conidia/mL B. bassiana spore suspension were 0, 20.00%, 86.67%, 90.00%, 96.67% and 100.00%, respectively, showing that the higher concentration of B. bassiana spore suspension, the higher infection rate of M. alternatus larvae. Furthermore, the test results of the effects of 1×109 conidia/mL B. bassiana spore suspension on M. alternatus larvae in different body size showed that the larger the larvae, the higher their mortality and infection rate. At 20 d post inoculation with 1×109 conidia/mL B. bassiana spore suspension, the mortality rates of M. alternatus larvae with the body size of 100-150, 200-220, 300-320, 400-420, 500-520 and 600-650 mg/individual were 76.67%, 76.67%, 66.67%, 93.33%, 100.00% and 100.00%, respectively, and the infection rates were 60.00%, 63.33%, 60.00%, 86.67%, 96.67% and 100.00%, respectively. 【Conclusion】 The concentration of B. bassiana spore suspension has significant effects on the mortality and infection rate of M. alternatus larvae, both of which increase with the increasing of spore concentration. Furthermore, the larger the larvae of M. alternatus, the higher their mortality and infection rate by B. bassiana. Our results provide new clues for the management of M. alternatus by using B. bassiana.
    Construction of transgenic Drosophila strains with carboxylesterase genes of Locusta migratoria (Orthoptera: Acrididae) and their roles in the metabolic detoxification of organophosphorus pesticides
    YIN Fei, YANG Yang, ZHANG Xu-Bo, ZHANG Jian-Zhen, ZHANG Jian-Qin
    2020, 63(7):  843-850.  doi:10.16380/j.kcxb.2020.07.008
    Abstract ( 546 )   PDF (1638KB) ( 69 )   PDF(mobile) (1638KB) ( 12 )     
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     【Aim】 To determine whether the carboxylesterase genes LmCesA1 and LmCesA2 of Locusta migratoria are involved in the metabolic detoxification of organophosphorus insecticides in vivo. 【Methods】 Two transgenic strains of Drosophila melanogaster were constructed by using Gal4/UAS system and transgenic technology. Three Gal4 strains (act-Gal4, tub-Gal4 and c601-Gal4) were selected to hybridize with transgenic Drosophila strains (UAS-LmCesA1 and UAS-LmCesA2) and the reference strain (RB0006{y v; attP40, y+}). The offspring of transgenic strains was verified at the DNA and RNA levels, and then the successfully constructed strains were screened out. The resistance of the offspring of the transgenic strains and Gal4 strains to malathion was detected by bioassay. 【Results】 The identification results of transgenic Drosophila at the DNA level showed that the target genes LmCesA1 and LmCesA2 were amplified in the transgenic strains tub>LmCesA1 and tub>LmCesA2, respectively, but not in the reference group (tub>attP40), while those at the RNA level revealed that the two genes were expressed in the corresponding hybrid offspring, indicating that the transgenic Drosophila strains were successfully constructed. Tissue expression profiles of the two target genes in adults of the transgenic Drosophila showed that LmCesA1 and LmCesA2 were highly expressed in the gut of the transgenic strains c601>LmCesA1 and c601>LmCesA2, respectively. In the transgenic strain c601>LmCesA1 the expression level of LmCesA1 in the gut was 7.6- and 16.7-fold as high as those in the brain and cuticle, respectively, while in the transgenic strain c601>LmCesA2 the expression level of LmCesA2 in the gut was 5.4- and 10.9-fold as high as those in the brain and cuticle, respectively. The results of insecticide bioassay demonstrated that compared with the F1 generation of hybrid strain in the reference group (c601>attP40), the hybrid offspring overexpressing LmCesA2 (c601>LmCesA2) showed significantly enhanced resistance to malathion, with the resistance ratio of 1.67. 【Conclusion】 The conclusion of this study is consistent with that of our previous research by RNAi combined with insecticide bioassay, i.e., LmCesA2 may be involved in the metabolic detoxification of malathion in L. migratoria.
    Mating behavior of Aromia bungii (Coleoptera: Cerambycidae) adults and their perching and oviposition preference on different host plants
    CHEN Jun-Rong, YAN Shi-Yao, CAO Dan-Dan, JING Jin-Rui, ZHANG Kuo, JIAN Kai-Min, MA Hai-Feng, WEI Jian-Rong
    2020, 63(7):  851-860.  doi:10.16380/j.kcxb.2020.07.009
    Abstract ( 593 )   PDF (2165KB) ( 168 )   PDF(mobile) (2165KB) ( 46 )     
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    【Aim】 The red-necked longhorn beetle, Aromia bungii, is a wood-borer of the tree species of the family Rosaceae, in which many species are fruit and ornamental trees. This study aims to ascertain the mating and oviposition behaviors of A. bungii adults and their perching and oviposition preference on different host plants. 【Methods】 Logs of eight host plants including Malus pumila, Prunus serrulata var. spontanea, Prunus persica, Malus micromalus, Prunus tomentosa, Pyrus ussuriensis, Prunus armeniaca, and Prunus cerasifera var. atropurea were chosen as the tested hosts, the mating and oviposition behaviors of A. bungii adults were observed, and the numbers of A. bungii adults perching on the eight host logs and the numbers of eggs laid on different host logs were determined by multi-selection experiments. 【Results】 The mating behaviors of A. bungii adults include three processes, i.e., avoiding, fighting and mating. The mating occurs in the order of three stages, i.e., encountering and pairing, mating attempt and ejaculation, and post-copulatory guarding. The females prefer to oviposit in bark crevices without gnawing a niche. The host log selection experiments showed that the females preferred to perch on P. persica logs, while the males preferred to perch on P. tomentosa logs. The logs of P. persica of the subfamily Prunoideae were the most favorite host for oviposition of A. bungii. Females laid very few eggs on the logs of M. pumila, M. micromalus and P. ussuriensis of the subfamily Maloideae. The results of correlation analysis showed that there was a positive correlation between the number of female adults perching on one host and the proportion of eggs laid on one host, and between the numbers of male and female adults perching on one host. 【Conclusion】 Female adults of A. bungii prefer P. persica logs rather than logs of other tree species. The preferences of male and female adults to hosts are not exactly the same.
    Trade-off between pollination and oviposition of the pollinator Ceratosolen sp. (Hymenoptera: Agaonidae) in monoecious Ficus racemosa
    WANG Xue-Min, MIAO Bai-Ge, PENG Yan-Qiong
    2020, 63(7):  861-869.  doi:10.16380/j.kcxb.2020.07.010
    Abstract ( 470 )   PDF (1848KB) ( 69 )   PDF(mobile) (1848KB) ( 16 )     
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    【Aim】 Ficus relies on the pollination of obligate wasps (Agaonidae) and provides the breeding place for the pollinator, which forms a classic coevolutionary relationship between plants and animals. In the receptive female figs, the wasp needs to pollinate and lay eggs within the limited survival time, and the balance between pollination and oviposition of wasp remains an open question. This study aims to ascertain the behavior and reproductive pattern of active pollinator Ceratosolen sp. in the receptive female figs of monoecious Ficus racemosa. 【Methods】 The style length of female flowers of F. racemosa and the ovipositor length of its pollinating fig wasps (Ceratosolen sp.) were measured under the microscope with micrometer, and the searching, oviposition and pollination behaviors of pollinating fig wasps were observed and recorded by video combined with the controlled experiments. After the pollinator was introduced to enter receptive female figs, the body sizes, egg loads, and pollen loads were measured at different stages. Finally, the numbers of fig wasp offspring and seeds in controlled figs were counted in male floral phase. 【Results】 The style length of female flowers of F. racemosa had variation between trees, but the ovipositor length of fig wasps was longer than the style length of most female flowers, indicating that the fig wasps can lay eggs in the ovaries of most female flowers. In general, larger pollinators had more egg loads, but the correlation between body size and pollen load was not significant. Behavioral observation showed that fig wasps mainly laid eggs in the first 6 h that they entered receptive female figs, laying about 95% of eggs in the ovaries. In receptive female figs, fig wasps averagely spent 27 s to search appropriate female flowers, and the oviposition time was averagely 46 s. During this period, the pollination behavior was rarely observed, and the number of pollen grains in pollen pockets did not vary significantly. After fig wasps entered the figs for 6-24 h, they mainly performed active pollination consistently and efficiently pollinated female flowers. The average time for pollination was 2 s, and at last 80% of the pollen loads were pollinated. The controlled experiment also confirmed that fig wasps mainly oviposited and produced their offspring in the first 6 h after entering fig, and then pollinated female flowers to produce fig seeds in the next 6-24 h. 【Conclusion】 In the receptive female figs of monoecious F. racemosa, fig wasps firstly lay eggs and then actively pollinate female flowers. The oviposition and pollination behaviors of fig wasps were exhibited for the first time, and the number of eggs laid and seed production matching the behaviors were determined, reflecting that the actively pollinated fig wasps have the tradeoff between pollination and oviposition about time and quantity.
    Chemotaxonomic analysis of scent gland secretions in Heteroptera based on GC-MS
    ZHANG Yan, XIA Yan, CHEN Qi-Fa, BU Wen-Jun
    2020, 63(7):  870-888.  doi:10.16380/j.kcxb.2020.07.011
    Abstract ( 415 )   PDF (1847KB) ( 53 )   PDF(mobile) (1847KB) ( 7 )     
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    【Aim】 Exploring the differences in chemical constituents of scent gland secretions among different groups in suborder Heteroptera contributes to finding out new characteristics for these insects and providing new evidence for the relationship among different taxa. 【Methods】 We analyzed the chemical profiles of scent gland secretions from 32 species of eight superfamilies of Heteroptera collected from China using solid phase microextraction (SPME) coupled with GC-MS. The chemotaxonomy of the secretions was analyzed by canonical discriminant analysis, nonparametric multivariate analysis of variance and canonical variate analysis at the superfamily level. 【Results】 The results of canonical discriminant analysis show that the compounds secreted by the scent glands exhibit significant variances among different superfamilies in Heteroptera and could be used as taxonomic characteristics for superfamilies in Heteroptera, especially in infraorder of Pentatomomorpha. The results of nonparametric multivariate analysis of variance also support significant variances among superfamilies. The combined results of canonical discriminant analysis and canonical variate analysis show that 30 major characteristic compounds in six groups are found in these insects, including acids (hexanoic acid, butanoic acid, and 2-hexenoic acid), alcohols [2-butyl-octan-1-ol, 2-hexyl-octan-1-ol, 2-hexyn-1-ol, 3,7-dimethyl-2-octen-1-ol, 4,8-dimethyl-1-nonanol, 2-decen-1-ol, 1-hexanol, cis-pinene hydrate, borneol, 2-bornanol, 1-methoxy-propan-2-ol, 2-ethyl-hexan-1-ol, (6Z, 9Z)-pentadecadien-1-ol, (E)-hexadecen-1-ol, (S)-3-ethyl-4-methyl-pentan-1-ol, isofenchol, and spathulenol], aldehydes [(E)-2-octenal, dodecanal, (Z)-3-hexenal, (E)-2-decenal, and (E, E)-2,4-decadienal], alkanes (2-methyl-hexane and 2,21-dimethyl-docosane), cyclics (furfural) and terpenes (neodihydrocarveol and dihydroterpineol). 【Conclusion】 The 30 characteristic compounds tentatively recognized from the scent secretions of the 32 species of eight superfamilies in Heteroptera can be used as the taxonomic characteristics of superfamilies and the evidences of relationship at the superfamily level.
    Research progress on Wolbachia endosymbionts in arthropods
    ZHU Xiang-Yu, YOU Shi-Jun, LIU Tian-Sheng, ZHANG Ling, YOU Min-Sheng
    2020, 63(7):  889-901.  doi:10.16380/j.kcxb.2020.07.012
    Abstract ( 584 )   PDF (2297KB) ( 179 )   PDF(mobile) (2297KB) ( 35 )     
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    Wolbachia is maternally inherited endosymbionts that can expand their propagation in host populations by means of various manipulations. It is estimated that 40%-60% of arthropods are infected with Wolbachia, which can be divided into multiple supergroups based on the phylogenetic relationships among different strains. To facilitate further studying the Wolbachia-mediated manipulation of hosts and associated mechanisms and developing more effective Wolbachia-based biological control strategies, in this article we made a systematical review of the research progress on Wolbachia. Wolbachia was first identified in the reproductive tissue of Culex pipiens in 1924 and verified to be associated with cytoplasmic incompatibility of hosts in 1971. Wolbachia can manipulate host reproduction through cytoplasmic incompatibility, male-killing, feminization, and parthenogenesis. In addition to reproductive manipulation, Wolbachia also affects metabolism, pathogen resistance, and fertility of hosts. The cytoplasmic incompatibility induced by Wolbachia can be interpreted by the “modification-rescue” model, and some functional genes involved in cytoplasmic incompatibility have been reported. wMel is the first Wolbachia strain whose genome was published, and dozens of Wolbachia strains were genomically sequenced afterwards. The wMel strain can inhibit the transmission of dengue virus, and integration of Wolbachia strains with sterile technology has shown promising effects in controlling field populations of Aedes albopictus. In view of the research progress on Wolbachia, future studies are suggested to focus on the following aspects: (1) Wolbachia genome and functional genes involved in reproductive regulation; (2) host-Wolbachia interactions and associated mechanisms; (3) application of Wolbachia in biological control programs.
    Progress and prospects of sex-separation techniques for dipteran insects
    PENG Wei, LI Yun-Xin, WENG Shi-Han, ZHOU Ruo-Han, PAN Xi, LI Jia-Yang, HAN Bao-Yu
    2020, 63(7):  902-912.  doi:10.16380/j.kcxb.2020.07.013
    Abstract ( 458 )   PDF (1525KB) ( 123 )   PDF(mobile) (1525KB) ( 11 )     
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     The sterile insect technique (SIT) has been used for decades to control agricultural and human health-related insect pests. Compared with insecticide control strategies, SIT has several attractive features including species-specificity and environmental friendliness. A major obstacle for SIT approach that involves the release of sterile males is the separation of males from females during the mass rearing stage in order to improve the cost-efficiency of these methods and to prevent the release of biting and disease-vectoring females. In most current genetic control programs targeting dipteran insects, sex separation is not used. Currently sex separation for a small number of dipteran insects is manually and mechanically achieved based on the pupal size or the difference in the eclosion time between female and male pupae. The molecular mechanism of sex determination and differentiation in dipteran insects varies, and exploration of the primary signal has revealed major differences. Several sex determination genes have been explored in the sex separation system. The sex ratio distortion strategy produces male-biased populations by disrupting the expression of the key genes in sex-determination pathway, and the conditional female death strategy achieves sex separation by using the sex-specific alternative splicing of the key genes in sex-determination pathway. Both of these two sex separation strategies are currently under evaluation for mass-rearing program in SIT. Differences in sexual dimorphism and genetic markers between females and males have been successfully employed in the visual separation strategy for dipteran insects. We reviewed the recent advances in sex ratio distortion, conditional female death strategy and visual separation strategy in dipteran insects. We assessed with emphasis the suitability of these methods in large-scale rearing of males for mass release in order to achieve more breakthroughs in the research of pest control based on the better sex-separation techniques.
    Contents of Vol. 63 Issue 7
    2020, 63(7):  913-913. 
    Abstract ( 264 )   PDF (482KB) ( 23 )   PDF(mobile) (482KB) ( 15 )     
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