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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 March 2022, Volume 65 Issue 3
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  • INTRODUCTION
    Chemical ecology in the era of omics: New missions of a traditional interdiscipline
    LI Jing-Jing, LIU Yang, WANG Gui-Rong, YAN Feng-Ming
    2022, 65(3):  257-260.  doi:10.16380/j.kcxb.2022.03.001
    Abstract ( 295 )   PDF (984KB) ( 144 )   PDF(mobile) (984KB) ( 48 )     
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    As a traditional interdiscipline, the content of chemical ecology is becoming more and more abundant in solving the problems of agricultural and forestry production and human health. Meanwhile, the application of new techniques has greatly promoted the development of the chemical ecology by deepening and widening our understanding of chemical communication among organisms. Articles in this special issue of “Insect Chemical Ecology” reflect, to a certain extent, the characteristics of chemical ecology research in China, i.e., agricultural and forestry orientation, application of both traditional and modern techniques, and almost keeping pace with international levels. In the era of omics, chemical ecology, with its interdisciplinary characteristics and by strengthening collaboration among scientists of different fields, will certainly play more important roles in different areas including food safety, ecological conservation, as well as for solutions of global climatic change.
    RESEARCH PAPERS
    Identification, expression and binding specificity of chemosensory proteins in the antennal transcriptome of the pea aphid, Acyrthosiphon pisum (Hemiptera: Aphididae)
    LIU Jing-Tao, WANG Qian, ZHAO Rui, WANG Huan-Huan, GAO Jie, DONG Hui, ZHANG Yong-Jun, CONG Bin, GU Shao-Hua
    2022, 65(3):  261-270.  doi:10.16380/j.kcxb.2022.03.002
    Abstract ( 289 )   PDF (7475KB) ( 146 )   PDF(mobile) (7475KB) ( 39 )     
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    【Aim】 This study aims to identify the chemosensory protein (CSP) genes in the antennal transcriptome of the pea aphid, Acyrthosiphon pisum, and to investigate the binding characteristics of antennae-enriched CSPs of A. pisum with aphid alarm pheromones, sex pheromones and plant volatiles.【Methods】 Based on the antennal transcriptome data of A. pisum, the CSP genes in antennae were identified. The expression profiles of these CSP genes in antennae and different tissues (antennae, stylet, head without antenna and stylet, thorax, abdomen, leg and wing) of A. pisum adults were assayed based on RPKM value and by semiquantitative RT-PCR, respectively. The binding characteristics of these CSPs in antennae with aphid alarm pheromones and sex pheromones, and plant volatiles were assayed by fluorescence competitive binding assay.【Results】 A total of ten CSP genes were identified from the antennal transcriptome of A. pisum adults. The RPKM value and semiquantitative RT-PCR results revealed that ApisCSP2, ApisCSP4 and ApisCSP5 were highly expressed in the antennae of A. pisum adults. The fluorescence competitive binding assays indicated that ApisCSP4 showed strong binding affinities to the main component of aphid alarm pheromone (E)-β-farnesene (EβF), and the minor component (-)-α-pinene, with the Ki values of 2.2±0.8 and 4.9±0.7 μmol/L, respectively. ApisCSP5 exhibited strong binding affinities to the two components of sex pheromones (+)-(4aS, 7S, 7aR)-nepetalactone and (-)-(1R,4aS,7S,7aR)-nepetalactol, with the Ki values of 4.8±0.9 and 2.6±0.6 μmol/L, respectively.【Conclusion】 There are ten CSP genes identified in the antennal transcriptome of A. pisum adults, among which ApisCSP4 and ApisCSP5 may be involved in the transport of aphid alarm pheromones and sex pheromones, respectively.
    Binding affinities of three SfruPBPs to sex pheromone and gland components from Spodopetera frugiperda and sympatric Leucania loreyi (Lepidoptera: Noctuidae)
    ZHENG Shu-Hao, SI Yu-Xiao, YAN Qi, GUO Hui-Fang, DONG Shuang-Lin
    2022, 65(3):  271-279.  doi:10.16380/j.kcxb.2022.03.003
    Abstract ( 149 )   PDF (1912KB) ( 69 )   PDF(mobile) (1912KB) ( 24 )     
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    【Aim】 This study aims to determine the binding characteristics of three pheromone binding proteins (PBPs) from the fall armyworm, Spodoptera frugiperda with sex pheromone and gland components of S. frugiperda and sympatric Leucania loreyi, and thus to investigate the roles of the three SfruPBPs in the recognition of pheromone components of these two species. 【Methods】 Plasmids were constructed using pET-30a(+) as the prokaryotic expression vector of the three SfruPBPs of S. frugiperda and introduced into Escherichia coli. After the OD600 value of the culture of E. coli reached 0.6-0.8, the three SfruPBPs were induced to express using IPTG, and purified by the Ni-NTA magnetic agarose beads. The binding characteristics of the three SfruPBPs with 14 sex pheromone and gland components of S. frugiperda and L. loreyi were assayed by fluorescence competitive binding assay. 【Results】 The recombinant PBP proteins SfruPBP1-3 were obtained by prokaryotic expression. Single target protein bands of expected size were obtained in the agarose gel electrophoresis after protein purification. Fluorescence competitive binding assay revealed that among the reported 14 sex pheromone and gland components of S. frugiperda and L. loreyi, SfruPBP1 had strong specific binding ability with the major pheromone component Z9-14∶Ac (Ki=0.80 μmol/L) of these two pest species, and SfruPBP2 displayed broad ligand spectrum, showing strong binding ability with the minor pheromone component Z7-12∶Ac and the gland components 12∶Ac, E7-12∶Ac and Z10-14∶Ac (Ki<1.00 μmol/L), and medium binding ability with the major pheromone component Z9-14∶Ac and the gland components Z9-12∶Ac and 11-12∶Ac (1.00 μmol/LZ9-12∶Ac, with the Ki value of 1.36 μmol/L. Among the chemicals with strong or medium binding affinities to SfruPBP, Z9-14∶Ac, Z7-12∶Ac and 12∶Ac were also sex pheromone or gland components of L. loreyi, however, all the three SfruPBPs showed no obvious binding ability with Z7-14∶Ac, a specific gland component in L. loreyi. 【Conclusion】 All the three SfruPBPs of S. frugiperda play important roles in the sex pheromone perception, but each SfruPBP displays a distinct selectivity to components. The three SfruPBPs show no obvious binding ability with the specific gland component Z7-14∶Ac of L. loreyi.
    Circadian rhythm of calling behavior and sex pheromone identification of Sylepta derogata (Lepidoptera: Pyralidae)
    ZHU Yu-Wei, SI Yu-Xiao, DENG Ying, LI Yu, DENG Jian-Yu, DONG Shuang-Lin, YAN Qi
    2022, 65(3):  280-288.  doi:10.16380/j.kcxb.2022.03.004
    Abstract ( 41 )   PDF (2287KB) ( 53 )   PDF(mobile) (2287KB) ( 17 )     
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     【Aim】 To observe the calling behavior and dynamic rhythm, and to identify the sex pheromone component of female moths of Sylepta derogata, so as to provide basis for the development of sex attractants and population forecast and green control of this pest insect. 【Methods】 The virgin female moths of S. derogata were placed individually in a plastic cup and their calling behavior was observed every half hour from 0.5 h before scotophase to 0.5 h after scotophase. The female sex pheromone glands were collected from virgin female moths during the peak calling period and extracted by hexane. The mchromatographic peaks of the active components of the sex pheromone gland extracts were analyzed by gas chromatography coupled with electroantennographic detection (GC-EAD), and the chemical structure information of the active components of the sex gland extracts was determined by GC coupled with mass spectrometry (GC-MS). 【Results】 The peak callingperiod of female moths of S. derogata was between the 4th and 7.5th hour into scotophase, and the 3-4 day-old female moths displayed the most active calling behavior. When female moths were calling, their antennae swinged from side to side, their wings vibrated rapidly, and the ovipositor kept extended. Two pheromone candidates, which could elicit strong EAG response of male moths, were detected in the extracts of the female sex pheromone glands by GC-EAD analysis, and the component with higher content was 10,12-16∶Ald detected by GC-MS and further identified as (10E,12Z)-10,12-hexadecadienal (E10,Z12-16∶Ald) by comparing the results of GC analysis between the pheromone gland extracts and the blend of synthetic standard compounds containing four 10,12-16∶Ald isoforms. Further EAG test showed that E10,Z12-16∶Ald could elicit a significant EAG response of male moths in a dose-dependent manner. 【Conclusions】 The 3-4-day-old female moths of S. derogata show the most active calling behavior, and the peak calling period of female moths is between the 4th and 7.5th hour into scotophase, and the major female sex pheromone component was identified as E10,Z12-16∶Ald, which needs to be confirmed by further field male trapping experiment.
    Responses of the rice leaffolder, Cnaphalocrocis medinalis (Lepidoptera: Crambidae) to sex pheromone and floral odor in olfactory behavior, and their application in its population monitoring
    GUO Qian-Shuang, ZHUO Fu-Yan, ZHU Jing-Quan, LIN Yu-Feng, ZHANG Zheng-Bing, HUANG De-Chao, ZHANG Su-Li, DU Yong-Jun
    2022, 65(3):  289-303.  doi:10.16380/j.kcxb.2022.03.005
    Abstract ( 172 )   PDF (2068KB) ( 78 )   PDF(mobile) (2068KB) ( 15 )     
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    【Aim】 To clarify the impact of the physiological state of the rice leaffolder, Cnaphalocrocis medinalis on its responses to sex pheromone and floral odor in olfactory behavior, and the dynamics of moth catches by sex pheromone and floral trapping in the field. 【Methods】 The moths of rice leaffolders were caught using net catching, and floral and sex pheromone trapping in the field in five test sites in Guangxi, Hunan, Zhejiang, and Sichuan in 2020. The differences in the olfactory behavior of moths caught by sex pheromone and floral trapping among the immigratory type (strong migratory type), local breeding type (residence and dispersal types), and emigratory type (strong migratory type) were compared by dissecting the ovaries and testes of moths. The number of larvae at each instar and their dynamics were investigated in the field according to the surveillance standards. The relationship between the dynamics of moths caught by sex pheromone and floral trapping and the population and occurrence time of larvae at each instar in the field was investigated, and the changes in the percentage of mature ovaries of female moths sampled by net catching and floral trapping with the physiological state of moths and season were analyzed as well.【Results】 The rice leaffolders of immigratory type may have mated during the migration, and entered a behavioral quiescent period after landing, causing them to first respond to sex pheromone, and then to floral ordor at the late stage of oviposition. The time difference between the moth peaks of sex pheromone and floral trapping was close to the pre-oviposition time. The moths of local breeding type showed a strong response to sex pheromone and sex pheromone trapping was very effective, but not to floral lure. The numbers of emigratory type  male moths caught by sex pheromone trapping and female and male moths caught by floral trapping were very low. The ovarian level of immigratory type female moths trapped by floral lures was relatively high, especially the percentage of oviposited female moths with level Ⅴ ovaries caught by floral trapping was much higher than that by net catching. For local breeding populations, the number of matings in female moths trapped by floral lure was significantly higher than that in female moths trapped by net catching in the field. For example, in Youxian, Hunan, the number of matings of female moths with level Ⅴovaries by floral trapping was 3.5±1.0, with the maximum value of 5, while the number of matings in female moths with level Ⅴ ovaries caught by net catching was 2.6±0.4, with the maximum value of 3. The male moths trapped by net catching had the largest testis volume, followed by those trapped by sex pheromone lure, and those caught by floral trapping had the smallest testis volume. The mortality rate of male moths by sex pheromone trapping was significantly lower than that of male moths caught by floral trapping. Floral trapping occurred throughout the night with the first peak appearing right after darkness, while sex pheromone trapping occurred from 1∶00 am until dawn. Analysis of trapping dynamics revealed the peak of moths of immigratory type trapped by sex heromone lure occurred earlier than that by floral lure. During the same period, by investigating the rice fields in Tianyang, Guangxi, and Youxian, Hunan, it was found that there was a correlation between the development and the number dynamics of larvae at each instar and the number of moth catches by sex pheromone trapping. 【Conclusion】 The correlation between the population and occurrence time of larvae at each instar and the number of C. medinalis moths caught by sex pheromone and floral trapping has been initially established in the rice fields, providing a technical basis for the precise application of pesticides in controlling the rice leafrollers in the field.
    Cotton plant volatiles induced by larval feeding of Agrotis segetum (Lepidoptera: Noctuidae) deter oviposition of conspecific females
    LI Meng-Yu, ZHANG Tao, XIA Shi-Ke, XIAO Hai-Jun, LU Yan-Hui
    2022, 65(3):  304-311.  doi:10.16380/j.kcxb.2022.03.006
    Abstract ( 139 )   PDF (1400KB) ( 90 )   PDF(mobile) (1400KB) ( 16 )     
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    【Aim】 The oviposition deterrence of herbivore-induced plant volatiles (HIPVs) from cotton plants damaged by the larvae of the turnip moth, Agrotis segetum, was evaluated on conspecific females, and the composition and functions of the major HIPVs were characterized in this study in order to identify the active components attracting or deterring adult oviposition.【Methods】 We identified HIPVs from cotton plants damaged by A. segetum larvae using a gas chromatography-mass spectrometer (GC-MS) and evaluated the electrophysiological activity and oviposition deterrent bioactivity of the major HIPVs to female adults of A. segetum using the electroantennogram (EAG) and oviposition cage bioassay method, respectively.【Results】 The female adults of A. segetum preferred to lay eggs on the healthy cotton plants over the damaged cotton plants, and the number of eggs laid on the healthy cotton plants was 6.59 times as high as that on the damaged cotton plants by A. segetum larvae. The HIPVs emitted from the cotton pants damaged by A. segetum larvae mainly consisted of benzaldehyde, linalool, β-caryophyllene, humulene, tetradecane, hexadecane, etc. Among them, benzaldehyde and linalool elicited strong EAG responses on the female antennae, showing a dose-response pattern. In the oviposition cage bioassay, linalool significantly deterred oviposition of female adults of A. segetum, while benzaldehyde attracted female adults to oviposit. 【Conclusion】 HIPVs emitted from cotton plants damaged by A. segetum larvae significantly deter oviposition of conspecific females, and linalool is considered as a potential oviposition deterrent.

    Effects of host switch on the development and digestive enzyme activities of Hyphantria cunea (Lepidoptera: Erebidae) larvae
    GENG Yi-Shu, ZHAO Xu-Dong, HAN Yang-Yang, QIAO Heng, HAO De-Jun
    2022, 65(3):  312-321.  doi:10.16380/j.kcxb.2022.03.007
    Abstract ( 22 )   PDF (1601KB) ( 55 )   PDF(mobile) (1601KB) ( 6 )     
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    【Aim】 This study aims to clarify the effects of host switch on the development and digestive enzyme activities of the larvae of the fall webworm, Hyphantria cunea, and to further explain the adaptive and physiological response mechanisms of H. cunea larvae after switching between different host plants.【Methods】 Under laboratory conditions, the first generation of H. cunea was reared on artificial diets. Following that the newly hatched larvae of H. cunea of the second generation were continuously reared on Taxodium distichum (T-T population) and Cerasus serrulata (C-C population), respectively. Then the larvae of H. cunea reached the 3rd instar, T-T and C-C populations were fed with their original and switched host plants, respectively, resulting in four treatment combinations: T-T population, C-C population, H. cunea population feeding on C. serrulata switching from feeding on T. distichum (T-C population), and H. cunea population feeding on T. distichum switching from feeding on C. serrulata (C-T population). Meanwhile, the growth and development parameters (developmental duration, larval survival rate, mean larval weight and pupal weight) of H. cunea larvae and the nutrition indices [relative growth rate (RGR), relative consumption rate (RCR), efficiency conversion of ingested food (ECI), efficiency conversion of digested food (ECD) and approximate digestibility (AD)] of the 5th instar larvae of the four treatments were tested. Furthermore, the activities of six digestive enzymes [total protease, high-alkaline trypsin, low-alkaline trypsin, chymotrypsin, amylase, and lipase] in the midgut of the 4th instar larvae of H. cunea during host switching were examined by the enzyme kinetics method. 【Results】 Under the conditions of host switch, there were significant differences in the developmental duration, pupal weight, and larval survival rate of H. cunea. The T-T population had the shortest larval and pupal duration and the highest larval survival rate, while the C-C population had the longest larval and pupal duration and the highest larval mortality rate. Meanwhile, there were significantly different growth and development indices of H. cunea larvae from earlier hosts after switching hosts. The RCR of the T-C population of H. cunea larvae was significantly lower than those of the other populations, and the ECI and ECD of the T-C population were significantly higher than those of the other populations. The AD of the T-C population was the lowest, while that of the C-C population was the highest.There was no significant difference in AD betweem the other two populations. After the host switching treatment, the digestive enzymes in the midgut of H. cunea larvae showed different activity levels. The trypsin activity in the larval midgut of the C-C population was significantly higher than those of the other populations, the chymotrypsin activity in the larval midgut of the C-C population was significantly higher than those of the T-T and T-C populations, the amylase activities in the larval migdut of the C-C and C-T populations were significantly higher than those of the other populations, and the lipase activity in the larval midgut of the T-C population was significantly lower than those of the other populations. 【Conclusion】 The growth, development, and digestive enzyme activities of H. cunea larvae have shown different degrees of differences after host switch. This study clarified the phenotypic plasticity and digestive physiological response of H. cumea after host switch. The results provide a foundation for revealing the adaptations of H. cunea to host plants and the mechanisms of plantmediated expansion into disaster risk.
    Electrophysiological responses of Protaetia brevitarsis (Coleoptera: Scarabaeidae) to host plant volatiles
    WANG Guang-Yu, ZHANG Meng-Meng, CHEN Li
    2022, 65(3):  322-332.  doi:10.16380/j.kcxb.2022.03.008
    Abstract ( 184 )   PDF (3284KB) ( 90 )   PDF(mobile) (3284KB) ( 40 )     
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     【Aim】 Protaetia brevitarsis is an economically important agricultural insect pest in China. This study aims to identify volatile compounds from apple, grape and corn under two states (healthy and damaged by P. brevitarsis adults) that elicit electrophysiological responses in antennae of female adults of P. brevitarsis. 【Methods】 Fruit volatiles from three fruits, apple, grape and corn, were collected by dynamic headspace adsorption technique. The active compounds in fruit volatile samples were screened by gas chromatography-electroantennogram detection (GC-EAD) technique and further identified by gas chromatography-mass spectrometry (GC-MS) analysis. All EAD-active compounds were quantitated by internal standard method. The active volatile compounds released by healthy and P. brevitarsis damaged fruits were evaluated by principal component analysis (PCA) and cluster analysis (CA). 【Results】Twentythree, 23 and 25 volatile compounds from apple, grape and corn, respectively, were found to be able to trigger EAD responses in female adults of P. brevitarsis. The volatile compounds in six treatments were divided into five groups by CA based on PC1 and PC2, which originated from healthy apple, damaged apple, healthy grape+damaged grape, healthy corn and damaged corn, respectively. There existed apparent differences in the main volatile components among the three fruits. As compared to heathy fruits, damaged fruits released significantly lower amounts of seven esters (2-methylbutyl acetate, propyl 2-methylbutyrate, amyl acetate, methyl hexanoate, butyl butyrate, hexyl acetate and hexyl isovalerate), but significantly greater amounts of three alcohols (2-methylpropanol, 2-methylbutanol and cis-3-hexenol). 【Conclusion】 The volatile compounds from the three fruits that trigger significant EAD responses of adult P. brevitarsis are mainly alcohols and esters. Damage by P. brevitarsis causes significant increase in contents of most alcohols and decrease in contents of esters. The attractiveness of the 58 EAD-active compounds identified in this study needs to be assayed by further laboratory and field experiments.
    Ultrastructure of antennal sensilla and electroantennographic responses to Allium mongolium volatiles in adult Galeruca daurica (Coleoptera: Chrysomelidae)
    LI Ling, LI Na, PANG Bao-Ping
    2022, 65(3):  333-342.  doi:10.16380/j.kcxb.2022.03.009
    Abstract ( 22 )   PDF (13437KB) ( 47 )   PDF(mobile) (13437KB) ( 12 )     
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    【Aim】 This study aims to clarify the types of antennal sensilla and electrophysiological responses of the adult Galeruca daurica to volatiles of host plants, so as to provide the necessary basis for further investigation on the mechanism of chemoreception in G. daurica. 【Methods】 The sensilla types on the antennae of G. daurica adults were observed using scanning electron microscopy (SEM). The volatiles were collected from the host plant Allium mongolium by headspace dynamic adsorption collection method, and the main components of volatiles were determined by GC-MS. The electrophysiological responses of G. daurica adults to the main volatile components of this host plant were determined by electroantennogram (EAG). 【Results】 There are five types of sensilla on the antennae of G. daurica adults, including sensilla trichodea (ST), sensilla chaetica (SC), sensilla basiconica (SB), sensilla campaniformia (SCa) and Bhm bristles (BB). Thirty-two volatile components were identified from A. mongolium. Among them, sulfur compounds accounted for 49.3%. EAG results showed that six compounds including diallyl sulfide, diallyl disulphide, (Z)-2-hexen-1-ol, 2-hexenal, methyl benzoate, and hexanal elicited relatively strong eletrophysiological responses in female adults of G. daurica, while only diallyl disulphide and 2-hexenal elicited relatively strong EAG responses in male adults. Moreover, most of the tested compounds elicited stronger EAG responses in female adults than in males. At the concentration of 1 mol/L, the tested six compounds except 2-hexenal could elicit the strongest EAG response in G. daurica adults. 【Conclusion】 Six compounds of A. mongolium can elicit strong EAG response of G. daurica adults, including diallyl sulfide, diallyl disulphide, (Z)-2-hexen-1-ol, 2-hexenal, methyl benzoate, and hexanal. The EAG responses of G. daurica adults to all these compounds except 2-hexenal increase with increasing concentrations.
    Extraction and identification of volatiles from Artemisia argyi and Torilis scabra and their effects on preference of Bemisia tabaci MED (Hemiptera: Aleyrodidae) adults
    XU Hui-Nan, MU Yang, ZHANG Zhan-Hong, ZHANG Zhuo, ZHANG De-Yong, TAN Xin-Qiu, SHI Xiao-Bin, LIU Yong
    2022, 65(3):  343-350.  doi:10.16380/j.kcxb.2022.03.010
    Abstract ( 112 )   PDF (1214KB) ( 48 )   PDF(mobile) (1214KB) ( 7 )     
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     【Aim】 In the previous study, we found that both Artemisia argyi and Torilis scabra have attractive or repellent effects on insects. However, there are no reports on the effects of A. argyi and T. scabra and their volatiles on Bemisia tabaci MED adults. Therefore, this study aims to test whether A. argyi and T. scabra and their volatiles could be used for green prevention and control of B. tabaci MED adults. 【Methods】 The preference of B. tabaci MED adults to four plants including Solanum lycopersicum, A. argyi, T. scabra and Cucumis sativus and olfactory responses of B. tabaci MED adults to A. argyi and T. scabra were detected by four-arm olfactometer and Y-tube olfactometer, respectively, and the components and relative contents of volatiles in A. argyi and T. scabra leaves were identified and analyzed by GC-MS. Finally, the olfactory responses of B. tabaci MED adults to the main volatiles of A. argyi and T. scabra leaves were detected by Y-tube olfactometer. 【Results】 The numbers of B. tabaci MED adults referring to S. lycopersicum and C. sativus (22 and 21, respectively) were significantly higher than those to A. argyi and T. scabra (16 and 9, respectively). Further determination of the selectivity of B. tabaci MED adults to A. argyi and T. scabra showed that the number of B. tabaci MED adults preferring to A. argyi (60) was extremely significantly higher than that to the blank control (22), while the number of B. tabaci MED adults preferring to T. scabra (22) was extremely significantly lower than that to the blank control (55). GC-MS analysis showed that the α-copaene content in A. argyi leaves was the highest, and the cyclohexene content in T. scabra leaves was the highest. Olfactory response tests indicated that the number of B. tabaci MED adults preferring to α-copaene (1 μg/L)(60) was extremely significantly higher than that to the blank control (24), and the number of B. tabaci MED adults preferring to cyclohexene (1 μg/L)(20) was extremely significantly lower than that to the blank control (62). 【Conclusion】 The volatiles of A. argyi leaves show strong attraction to B. tabaci MED adults, and the volatiles of T. scabra leaves show strong repellency to B. tabaci MED adults. Therefore, the volatiles of A. argyi and T. scabra leaves can be used as food attractant or repellent to control B. tabaci MED adults effectively.

    REVIEW ARTICLES
    Application of semiochemicals in insect pest monitoring
    ZHANG Zhen, WANG Hong-Bin, CHEN Guo-Fa, KONG Xiang-Bo, ZHANG Su-Fang, LIU Fu
    2022, 65(3):  351-363.  doi:10.16380/j.kcxb.2022.03.011
    Abstract ( 114 )   PDF (3633KB) ( 104 )   PDF(mobile) (3633KB) ( 34 )     
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     Population monitoring is an important step in population prediction and decision making of pest management. Compared with other labour-intensive sampling survey of different developmental stages and host damage levels of insect pests, semiochemical-based monitoring is simple, labor-saving, low cost, species-specific, sensitive under low population density and can be used in large scale. The applications of semiochemicals include three aspects: (1) detection of insect distribution and the species in certain area; (2) monitoring of the occurrence period of insect pests; and (3) monitoring of population levels or the damage degree. The reliability of the first two aspects is positive, while the third aspect is complex and controversial with both positive and negative examples. In this article we analyzed the existing application researches of semiochemicals in pest monitoring in China and other countries and explored the way to make the monitoring and prediction more reliable. There are many factors which influence the monitoring of semiochemials and forecast of population density, such as the component, composition, dose and releasing rate of semiochemicals, the type and design of traps in the field, the biology, population dynamics and phases of monitored species, field conditions e.g. biological factors including host species, species composition, host age, host density and so on, and abiotic factors like weather), damage estimate method, the prediction model used and the modeling method. Based on the study and analysis to make the semiochemical-based monitoring reliable, one should use correct composition and proportions of semiochemicals, appropriate dosage, and stable and persistent release rate of the semiochemical carriers. One also needs to choose a unified trap type, setting method and density. In addition, population level or host damage degree estimating method and prediction models should be taken based on the studies for a particular pest species and its environment so as to form the systematic monitoring standard and procedure. Semiochemical-based pest monitoring is reliable if a rational monitoring protocol is made according to the characteristics of a particular species and its environment.
    Research methods and advances of odorant receptors in insects
    BAI Peng-Hua, WANG Bing, ZHANG Xian-Hong, WANG Gui-Rong
    2022, 65(3):  364-385.  doi:10.16380/j.kcxb.2022.03.012
    Abstract ( 181 )   PDF (2283KB) ( 100 )   PDF(mobile) (2283KB) ( 39 )     
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    Insect odorant receptors (ORs) play critical roles in the peripheral olfactory system and are involved in such vital life events in insects as feeding, mating and oviposition. With the development of sequencing technologies and bioinformation tools, insect OR genes have been widely identified in recent years. In this article, we comprehensively reviewed the research methods of insect OR genes, and their principles, advantages and disadvantages. Furthermore, we summerized the numbers and proportions of research methods published for identification and functional studies of ORs since 2015. Besides, we listed the research advances of ORs in serious insect pests. A total of 2 543 and 5 111 OR genes had been respectively identified through genome and transcriptome sequencing analyses during 2015 to 2019. Gene expression and protein localization analysis are used to analyze the expression specificities of OR genes in different tissues and developmental stages. The in situ hybridization and immunohistochemistry are used for analyzing cellular and tissue localization, while the semi-quantitative reverse transcription PCR (RT-PCR) and quantitative real-time PCR (qRT-PCR) are often used to study the spatiotemporal expression profiles of OR genes. Otherwise, cryo-electron microscopy (Cryo-EM) is employed to elucidate the OR micro-crystal structure and to demonstrate the interactions between critical amino acid residues and ligands. Multiple approaches are developed for functional characterization of ORs. In vitro heterologous expression systems are commonly used to study the function of insect ORs, representing 75.76% of the research methods published from 2015 to 2019. The most abundantly used in vitro systems are through heterologous expression in Xenopus oocytes with two-electrode voltage clamp system (43.94%), followed by transgenic Drosophila with single sensillum recording (SSR) technique and cell line expression systems with calcium imaging. In vivo research methods include RNA interference (RNAi) and clustered regularly interspaced short palindromic repeats (CRISPR)-associated nuclease Cas9 (CRISPR/Cas9) gene edting technique. The latter has made great breakthroughs in OR deorphanization, and has a great prospective application for further studies. Finally, we suggest the future research directions for insect ORs including, (1) studying the molecular mechanism of olfaction in serious insect pests and natural enemies; (2) elucidating the molecular mechanism of synergism to insect sex pheromones and host plant volatiles; (3) analyzing the micro-crystal structure of ORs and explore the specific recognition mechanisms of ORs and odorants; and (4) developing behavioral regulation products in insects through RNAi technique.
    Research progress of the mechanism of CO2 perception in insects
    CHEN Qiu-Yan, LIU Yang, WANG Gui-Rong
    2022, 65(3):  386-398.  doi:10.16380/j.kcxb.2022.03.013
    Abstract ( 113 )   PDF (1585KB) ( 85 )   PDF(mobile) (1585KB) ( 12 )     
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     Carbon dioxide (CO2) is an important component of air. It is not only one of the main raw materials for plant photosynthesis, but also directly affects the life activities of insects as a chemical signal. CO2 plays an important role in the foraging behavior of Diptera, Coleoptera and Lepidoptera. CO2 can affect the oviposition behavior of flies and moths. CO2 is an important indicator for social insects to adjust the climatic conditions in the nest. The research on the mechanism of CO2 perception in insects can help to better understand the chemosensory systems in insects, and may also provide some new strategies for pest monitoring and control. Since the two CO2 receptor genes GR21a and GR63a co-expressed in Drosophilia were indentified in 2017, CO2 receptor genes of many insect species have been identified with the development of high-throughput sequencing techniques combined with sequence homology analysis. For this reason, the major breakthrough has been made in the research for the mechanism of CO2 perception at the peripheral nervous system level in insects. The CO2 receptor genes of insects are expressed on specific receptor neurons, which have the ability of sensing small fluctuations in the external CO2 in the environment and further transmit the CO2 signal to the central nervous system of the brain. The transduction of CO2 signal in the central nervous system can be divided into the processing in the primary brain center-antennal lobe and the processing in the higher brain center in insects. CO2-projecting neurons form complex dendrites within specific glomerulus in the antennal lobe, and then continue to project toward the lateral horn and upward to the mushroom body of the higher centers in the brain. Homologous genes of CO2 receptor genes have not been identified in the genomes of some insects, but the responses of these insects to CO2 have been reported earlier, suggesting that other pathways sensing CO2 exist in these insects. We summarized the related research progress from four aspects: the importance of CO2 for the life activities of insects, the mechanism of CO2 perception at the peripheral level in insects, the mechanism of CO2 perception at the central nervous system level in insects, and other CO2 perception pathways in insects. We also emphatically introduced the effects of CO2 on insects and the identification and functional research of CO2 receptor genes, providing some useful ideas and methods for the further study on the mechanism of CO2 perception and the development of green prevention and control.
     Research progress of induced defense against insect pests in tea plant (Camellia sinensis)
    ZHANG Jin, XING Yu-Xian, HAN Tao, YU Guang-Wei, SUN Xiao-Ling
    2022, 65(3):  399-408.  doi:10.16380/j.kcxb.2022.03.014
    Abstract ( 120 )   PDF (1315KB) ( 101 )   PDF(mobile) (1315KB) ( 20 )     
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     Confronted with herbivores, plants have evolved a sophisticated network of defense, which can be classified as constitutive and induced. After perceiving herbivore-derived molecular via receptors, the tea plant (Camellia sinensis) will initiate early signaling events, and then activate multiple signaling pathways of plant pheromones, such as jasmonic acid (JA), salicylic acid (SA), ethylene (ET), gibberellin and other phytohormones, resulting in the accumulation of secondary metabolites, and eventually induce direct and indirect resistances to pests. Based on the recent research progress in tea plant defense responses induced by main insect pests and their regulatory mechanisms, we summarized the components and ecological functions of herbivore-induced plant volatiles (HIPVs) of the tea plant, and their application in green pest control, uncovered the important defense signaling network involved in the regulation of insect-induced resistance in the tea plant, emphasized on the research progress of the JA pathway in the tea plant, and proposed suggestions for future research. The infestation of Ectropis obliqua, Matsumurasca onukii and Myllocerinus aurolineatus induces 17 shared volatiles from tea plants, but induces eight, three and two specific volatiles from tea plants, respectively. Among the above volatiles, five, one and six volatiles were found to have attractiveness to E. obliqua, M. onukii and M. aurolineatus, respectively, while two volatiles and one volatile are involved in the repellence against E. obliqua and M. onukii, respectively. Thus, the attractants to these three insect species and the repellents against M. onukii have been screened out. The JA pathway and SA pathway are the two main pathways involved in the defense responses in tea plants to multiple insect pests, and the JA pathway plays a vital role. Meanwhile, several plant hormones, including auxin, abscisic acid, gibberellin, etc., also take part in tea plant induced defense processes. So far, many genes associated with JA biosynthesis and regulation have been cloned and characterized. Based on the understanding of their functions in tea plant resistance against insects, the fact that JA pathway positively regulates direct or indirect tea plant resistance to insects was revealed. We suggest that the further study should focus on further clarifying the molecular mechanisms of insect-induced resistance in the tea plant, and the utilization of induced defense against insect pests in tea plants. This article will provide guidance for in-depth research on the molecular mechanisms in induced resistance in the tea plant and further development of green pest prevention and control technologies.

    CONTENTS
    Contents of Vol. 65 Issue 3
    2022, 65(3):  409-409. 
    Abstract ( 55 )   PDF (499KB) ( 21 )   PDF(mobile) (499KB) ( 7 )     
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