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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 August 2023, Volume 66 Issue 8
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  • RESEARCH PAPERS
    Identification and pathogenicity determination of Beauveria bassiana strain JCF from Holotrichia oblita (Coleoptera: Scarabaeidae)
    CAO Wei-Ping, CHENG Jia-Xu, FENG Shuo, ZHAO Ju-Ying, CHEN Dan, SONG Jian
    2023, 66(8):  999-1008.  doi:10.16380/j.kcxb.2023.08.001
    Abstract ( 155 )   PDF (14504KB) ( 154 )   　　
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    【Aim】 Holotrichia oblita is an important insect pest of various crops such as peanuts, fruit forests and nurseries, and it has been mainly controlled by chemical control for a long time. In this study, the pathogenicity of Beauveria bassiana strain JCF to the larvae and adults of H. oblita was determined to provide fungal resources for the biological control of H. oblita. 【Methods】 The parasitic fungi on the dead body of the diseased H. oblita were isolated and rejoined, and the pathogenic strain JCF was isolated and purified. The morphological characteristics of the strain were observed by light microscope. The rDNA-ITS sequence of JCF was amplified by PCR and then sequenced, and the phylogenetic tree of JCF was constructed for molecular identification. The virulence of the JCF strain to the adults and larvae of H. oblita was determined by immersion method and field simulation test. 【Results】 The colony of the strain JCF with colorless back is white fluffy at the initial stage, then becomes yellow or light yellow flocculent at the late stage. The conidiogenous cells are clustered on the conidiophore in a bottle shape, and the conidiophore is spike-shaped and attached to the vegetative hypha. Conidia are solitary, transparent, subglobose, and (2.0-3.5) μm×(1.5-2.0) μm in diameter. The molecular identification of rDNA-ITS sequence showed that the strain JCF was B. bassiana. The medium lethal concentration (LC50) value of B. bassiana strain JCF against H. oblita adults was 2.124×107 conidia/mL, and the medium lethal time (LT50) values of this strain at the concentrations of 2×108, 1×108 and 5×107 conidia/mL against H. oblita adults were 6.267, 6.852 and 7.455 d, respectively. The LC50 values of B. bassiana strain JCF against the 1st, 2nd and 3rd instar larvae of H. oblita were 5.47×106, 1.59×108 and 2.50×108 conidia/mL, respectively. The LT50 values of B. bassiana strain JCF at the concentration of 1×108 conidia/mL against the 1st and 2nd instar larvae of H. oblita were 8.6 and 18.6 d, respectively, and those of B. bassiana strain JCF at the concentration of 5×108 conidia/mL against the 2nd and 3rd instar larvae were 10.3 and 13.2 d, respectively. In the field simulation test, the spore suspension of B. bassiana strain JCF (2×108 conidia/mL) exhibited good pathogenic effects on both adults and larvae of H. oblita.【Conclusion】 The B. bassiana strain JCF has high pathogenicity to the adults and larvae of H. oblita, providing a new strain resource for the development of B. bassiana formulations to control Melolonthidae pests. And it has potential application value for biological control of Melolonthidae pests.
    Screening and simulated field efficacy evaluation of Beauveria bassiana with high virulence to Holotrichia parallela (Coleoptera: Scarabaeidae) larvae
    ZHU Chang-Jian, MA Yu-Meng, LI Bin, LIANG Jia-Hui, CAO Fu, YANG Yang, LIU Su, LI Mao-Ye
    2023, 66(8):  1009-1019.  doi:10.16380/j.kcxb.2023.08.002
    Abstract ( 130 )   PDF (24584KB) ( 154 )   　　
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    【Aim】 To screen Beauveria bassiana strains with high virulence against Holotrichia parallela larvae and to evaluate the simulated field efficacy of the strain with the highest virulence in combination with azadirachtin and phoxim, respectively.【Methods】 The virulence of 10 strains of B. bassiana to the 3rd instar larvae of H. parallela was evaluated based on the corrected mortality and medium lethal time (LT50) value using the insect dipping method. Furthermore, the medium lethal concentration (LC50) values of the screened Bb14 strain against the 1st and 3rd instar larvae of H. parallela were determined. In the pot experiments, the conidial suspension of Bb14 (1×108 conidia/mL) was applied in combination with azadirachtin (3 mg/L) and phoxim (200 mg/L), respectively, and the control efficacy against the 3rd instar larvae of H. parallela on tobacco seedlings was evaluated in greenhouse.【Results】 Among the 10 strains of B. bassiana at the concentration of 1.0×108 conidia/mL, Bb14 had the highest virulence against the 3rd instar larvae of H. parallela, causing the cumulative corrected mortality of 76.67% in 17 d and with the LT50 value of 11.14 d. The LC50 values of Bb14 infecting the 1st and 3rd instar larvae of H. parallela were 0.32×107 and 0.68×107 conidia/mL, respectively. In the pot experiments, the control efficacy of Bb14, azadirachtin and phoxim against the 3rd instar larvae of H. parallela was 42.86%, 64.29% and 82.14%, respectively, at 25 d after application. At 25 d after applying Bb14 in combination with azadirachtin and phoxim, respectively, the control efficacy against the 3rd instar larvae of H. parallela reached 78.57% and 92.86%, respectively. 【Conclusion】 Among the tested 10 strains of B. bassiana, Bb14 has the highest virulence to H. parallela larvae. The application of Bb14 in combination with azadirachtin and phoxim leads to improved control efficacy against H. parallela larvae.
    Analysis of differences in the midgut bacterial composition and function between different Bombyx mori varieties at the 5th instar larval and pupal stages
    LI Qing-Rong, YANG Qiong, XING Dong-Xu, ZOU Yu-Xiao, ZHANG Wei-Long, XIAO Yang
    2023, 66(8):  1020-1030.  doi:10.16380/j.kcxb.2023.08.003
    Abstract ( 130 )   PDF (2487KB) ( 271 )   　　
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    【Aim】 To analyze the differences in the midgut bacterial composition among different varieties of Bombyx mori with different vitalities and cocoon shell ratios, and their effects on the related traits such as vitality and cocoon shell ratio. 【Methods】 Based on the results of the long-term feeding survey on B. mori resource, the variety 932G with high vitality and the variety 2041J with high silk yield were selected as experimental materials, the midguts of the 5th instar larva and pupa were collected, and the 16S rDNA sequences of the midgut bacteria were sequenced and analyzed by the high-throughput sequencing platform to compare the differences in the composition and function of the midgut bacteria between different varieties and different developmental stages of B. mori. 【Results】 A total of 399 and 453 operational taxonomic units (OTUs) of the midgut bacteria were obtained from 932G and 2041J at the 5th instar larval stage, and 138 and 162 OTUs of the midgut bacteria were obtained from 932G and 2041J at the pupal stage, respectively. The dominant phyla of the midgut bacteria of B. mori at the 5th instar larval stage were Proteobacteria, Firmicutes and Actinobacteriota, and the dominant genus was Methylobacterium with the highest abundance, followed by Staphylococcus. However, there were significant differences in the relative abundance of some genera between the two varieties. The relative abundance of some genera including Devosia, Ralstonia, Nitrospira, Brachybacterium, Rothia, Lawsonella etc. in the midgut of the 5th instar larva of 932G was significantly higher than that in the midgut of the 5th instar larva of 2041J. The relative abundance of Pseudomonas, Methylobacterium, Acinetobscter, Cloacibacterium, Leuconostoc, Propionibacteriaceae, Psychrobacter, Sphingobium, Bacteroides etc. in the midgut of the 5th instar larva of 2041J was significantly higher than that in the midgut of the 5th instar larva of 932G. There were 77% and 78% functional genes in the midgut bacteria of the 5th instar larvae of 932G and 2041J enriched on the metabolic pathways of KEGG, respectively, followed by those of the function genes enriched on the environmental information processing and genetic information processing. The proportions of the midgut bacterial communities involved in nitrate reduction, nitrogen respiration, nitrate respiration, nitrite respiration and nitrogen fixation in the 5th instar larva of 932G were higher than those in 2041J. The proportions of the midgut bacterial communities involved in chemical heterotrophic, urea decomposition and methanol oxidation in the 5th instar larva of 2041J were higher than those in the 5th instar larva of 932G. The difference in the midgut bacterial composition between the 5th instar larva and pupa was significant. Erwinia of Proteobacteria in the midgut of the pupa was the dominant genus, and there was no significant difference in the relative abundance of Erwinia between the two varieties at the pupal stage. The relative abundance of functional genes involved in amino acid transport and metabolism, extracellular secretion and transport, carbohydrate transport and metabolism, and inorganic salt transport and metabolism of the midgut bacteria in the pupa was significantly higher than that in the 5th instar larva of 932G.【Conclusion】 There were significant differences in the midgut bacterial composition and predicted function between the varieties 932G with high vitality and 2041J with high silk yield of B. mori at the 5th instar larval stage. The composition and function of the midgut bacteria of B. mori at the pupal stage were significantly different from those of B. mori at the 5th instar larval stage, and there was no significant difference in the relative abundance of midgut bacteria between the two varieties at the pupal stage. These research results can provide a reference for further exploring the role of gut microorganisms in stress resistance, drug resistance, disease resistance, protein synthesis and transformation of B. mori and variety breeding.
    Diversity analysis of the midgut bacteria in Culex quinquefasciatus (Diptera: Culicidae) adults before and after blood meal or infection with Japanese encephalitis virus
    XU Chang-Hao, ZHU Xi, HE Yi, LIU Yu-Wei, HUANG Yu-Tian, LI Rui-Dong, CAO San-Jie, HUANG Xiao-Bo, YAN Qi-Gui, WU Rui, WEN Yi-Ping, LANG Yi-Fei, ZHAO Qin, ZHAO Shan, WANG Yi-Ping, HU Ya-Jie, DU Sen-Yan
    2023, 66(8):  1031-1041.  doi:10.16380/j.kcxb.2023.08.004
    Abstract ( 87 )   PDF (2487KB) ( 141 )   　　
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    【Aim】 To study the midgut bacterial diversity and difference in Culex quinquefasciatus adults before and after feeding with blood meal and infection with the Japanese encephalitis virus (JEV), then further reveal the relationship between C. quinquefasciatus and its midgut bacteria, as well as the reasons for the changes of the midgut bacteria during blood digestion and viral infection.【Methods】 The bacterial genome DNA of the midguts from C. quinquefasciatus adults fed with sugar water (10% sucrose solution), blood meal without JEV and blood meal with JEV was extracted. The 16S rDNA highly variable region sequence of the midgut bacteria was amplified by PCR, sequenced using the Illumina NovaSeq6000 sequencing platform and analyzed by bioinformatics. The total RNA was extracted from the midguts of C. quinquefasciatus adults fed with blood meal without JEV and blood meal with JEV, and the expression levels of the antimicrobial peptide (AMP) genes CqAttacin, CqCecropin, CqCecropin A, CqDefensin A and CqDefensin C in the midgut were detected by RT-qPCR.【Results】 There were 204 amplicon sequence variants (ASVs) in the midgut bacteria of C. quinquefasciatus adults before and after blood meal, belonging to 4 phyla, 9 classes, 17 orders, 27 families and 36 genera, and 120 ASVs in the midgut bacteria before and after infection with JEV, belonging to 6 phyla, 13 classes, 23 orders, 38 families and 47 genera. At the genus level, Elizabethkingia was widely distributed in the midgut bacteria as a dominant genus. The abundance of Enterobacter in the midgut of C. quinquefasciatus adults was the highest on the day 2 after blood meal. Morganella, Rhizobium and Bordetella mainly existed in the midgut of C. quinquefasciatus adults infected with JEV. The difference in the metabolic pathways of the midgut bacteria between C. quinquefasciatus adults on the day 2 after being fed with sugar water and blood meal was the largest. The main differential metabolic pathways were the phosphotransferase system, biosynthesis of siderophore group nonribosomal peptides, N-glycan biosynthesis, fatty acid biosynthesis and the metabolic pathways of amino acids. There were differences in the midgut microbiota between C. quinquefasciatus adults infected with and without JEV, and the midgut bacterial abundance of C. quinquefasciatus adults was higher after JEV infection. Blood meal upregulated the expression levels of the AMP genes CqAttacin, CqCecropin, CqCecropin A, CqDefensinA and CqDefensin C in the midgut compared with the control group fed with sugar water, while infection with JEV significantly downregulated the expression levels of the AMP genes CqCecropin A, CqDefensin A and CqDefensin C in the midgut of C. quinquefasciatus adults compared with blood meal without JEV.【Conclusion】 Both the blood meal and JEV infection lead to the changes of midgut bacteria of C. quinquefasciatus adults. The former shows that the blood digestion process is selective for the midgut bacteria, while the latter may be related to the downregulation of the expression levels of AMP genes in the midgut of C. quinquefasciatus adults caused by JEV infection.
    AsCYP9J5 of Anopheles sinensis (Diptera: Culicidae) is involved in deltamethrin resistance
    GUO Ying-Ao, HAN Bao-Zhu, QIAO Liang, CHEN Bin
    2023, 66(8):  1042-1051.  doi:10.16380/j.kcxb.2023.08.005
    Abstract ( 111 )   PDF (3843KB) ( 146 )   　　
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     【Aim】 To investigate whether the cytochrome P450 gene of Anopheles sinensis (AsCYP9J5) is related to the deltamethrin resistance of An. sinensis.【Methods】 The open reading frame of AsCYP9J5 was cloned by PCR and analyzed by bioinformatics. The expression levels of AsCYP9J5 in the female pupa and female adult of deltamethrin-sensitive strain (WX-LS) and deltamethrin-resistant strains (YN-LR and CQ-LR), in the head, thorax, first 3 abdominal segments (anterior part of abdomen) and remaining parts of abdomen (posterior part of abdomen) of female pupa of WX-LS, and in the head of the WX-LS female pupa in vitro cultured with 25 mg/mL deltamethrin solution were detected by RT-qPCR. Based on the above expression levels of AsCYP9J5, dsAsCYP9J5 and dsEGFP were injected into the head of female pupa for RNAi at 20 h after pupation of YN-LR and CQ-LR, the expression level of AsCYP9J5 in adults was detected by RT-qPCR, the half knockdown time (KT50), knockdown rate and mortality rate of adults after deltamethrin treatment were counted. The amino acid residues interacting between AsCYP9J5 and deltamethrin were predicted by molecular docking simulation. 【Results】 The open reading frame of AsCYP9J5 was cloned and is 1 626 bp in full-length, encoding 541 amino acids without signal peptide and transmembrane domain. The expression levels of AsCYP9J5 in YN-LR and CQ-LR at different developmental stages were different. The expression level of AsCYP9J5 in YN-LR was significantly higher than that in WX-LS from late instar pupa to the 9 h-old adult. In WX-LS and CQ-LR, AsCYP9J5 was highly expressed from the 30 h-old pupa to the 72 h-old adult. The expression levels of AsCYP9J5 in CQ-LR at different developmental stages (except 20 h-old pupa) were significantly higher than those in WX-LS. The expression level of AsCYP9J5 in the head of the WX-LS female pupa was the highest, followed by that in the throax, while those in the anterior part and the posterior part of the abdomen were similar and the lowest. The expression level of AsCYP9J5 in the head of the WX-LS female pupa at 12 h after the deltamethrin induction was up-regulated by 11-fold as compared with that in the control group, and that at 24 h was slightly lower than that in the control group. In YN-LR and CQ-LR injected with dsAsCYP9J5, the expression levels of AsCYP9J5 of the adult decreased by about 68% and 38%, the knockdown phenotype of the adult appeared about 10 and 20 min earlier, the knockdown rates of the adult were significantly increased and the mortality rates of the adult were increased by 28.6% and 24.0%, respectively, as compared to those in the control injected with dsEGFP, indicating that silencing AsCYP9J5 resulted in a significant increase in susceptibility of An. sinensis to deltamethrin. Molecular docking simulation result showed that deltamethrin can enter the binding pocket of AsCYP9J5 and form a binary Pi-cation interaction with Arg-488, a stable T-type Pi-Pi stack with Phe-109 of AsCYP9J5, and Pi-sulfur and Pi-lone pair electron interactions with Cys-348 and Thr-344. The side chain of deltamethrin can also form a stable hydrogen bonding interaction with Gln-224 of AsCYP9J5, as well as a stable hydrophobic interaction network with Ile-227, Leu-413 and Lys-53 of AsCYP9J5.【Conclusion】 The results of this study suggest that AsCYP9J5 is involved in the maintenance of deltamethrin resistance phenotype in An. sinensis, which might lay a foundation for further investigation of the molecular mechanism of AsCYP9J5 in the metabolism of deltamethrin.
    Biological characters and loop-mediated isothermal amplification detection of Planococcus lilacinus (Hemiptera: Pseudococcidae)
    HUANG Peng, ZHANG Jie, YAO Jin-Ai, LAN Yan-Yang, YU De-Yi
    2023, 66(8):  1052-1062.  doi:10.16380/j.kcxb.2023.08.006
    Abstract ( 84 )   PDF (25600KB) ( 103 )   　　
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     【Aim】 To define the biological characters of Planococcus lilacinus and achieve its visual detection. 【Methods】 The morphological characteristics and duration of different developmental stages and female adult fecundity of P. lilacinus were determined in the laboratory. Then based on the 28S rDNA sequence of P. liacinus, the specific primers of loop-mediated isothermal amplification (LAMP) were designed to establish the corresponding visual detection method, and the specificity, sensitivity and stability of LAMP detection were verified. 【Results】 The female and male P. lilacinus have different generational life histories. From the egg when it is laid, the outline of insect body and one pair of dark red ocelli just can be seen. The 1st instar nymph moves fast and it is difficult to identify its female and male. The 2nd instar nymph has thin white wax rods on the body margins with differentiated body morph between female and male. The 3rd instar nymph only belongs to female and has similar shape to female adult. The pupa only belongs to male and includes prepupal and pupal stages. The female adult is covered by thick white wax powders, with 18 pairs of visible wax rods on the body margins. The male adult has one pair of transparent and developed fore wings, and one pair of long white wax filament at the terminal part of the abdomen. The duration of egg and female adult lasted (1.37±0.26) h and (32.67±4.82) d, respectively, while that of each instar nymph, pupa and male adult all lasted no more than (7.65±0.82) d. Meanwhile, the number of eggs laid per female and the egg hatching rate in sexual reproduction were (531.92±69.98) grains and 96.02%±1.35%, respectively, while those in parthenogenetic reproduction were (403.50±71.11) grains and 88.41%±3.03%, respectively. Furthermore, the established LAMP visual detection method could effectively amplify the DNA of P. lilacinus, it had the optimal reaction temperature of 66 ℃, optimal reaction time of 55 min, detection limit of at least 100 fg/μL and detection rate of 91.67%-100.00% with the positive green reaction products. But the LAMP detection could not amplify the DNA of the other seven mealybug species with the negative saffron yellow reaction products. 【Conclusion】 There is sexual dimorphism in P. lilacinus life cycle with fast growth and development and strong fecundity, therefore it is necessary to be detected and monitored. The LAMP visual detection method is rapid, specific, sensitive and reliable, it shows an excellent potential in rapid and accurate identification of this mealybug for non-professional identifier on-site.
    Flight capacity and energy utilization mode in the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) during flight
    YANG Fan, ZHENG Min, HOU Xiao-Yu, LI Si-Yi, ZHOU Li-Lin, LI Chao, WANG Pan, SI Sheng-Yun
    2023, 66(8):  1063-1074.  doi:10.16380/j.kcxb.2023.08.007
    Abstract ( 90 )   PDF (4544KB) ( 127 )   　　
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    【Aim】 To clarify the flight capacity and energy utilization mode in adults of the diamondback moth (Plutella xylostella) during flight. 【Methods】 The flight capacities of the unmated female and male adults of P. xylostella at different day-old ages were examined by tethered flight on a computerized flight mill. After the field population was reared for three (F3) and twenty (F20) generations in laboratory, the differences in flight capacity were compared among various populations. The changes in contents of triglyceride and soluble sugar, and the activities of six key enzymes related to energy metabolism, including glyceraldehyde-3-phosphate dehydrogenase (GAPDH), trehalase (TRE), glycerol 3-phosphate dehydrogenase (GPD), lactate dehydrogenase (LDH), 3-hydroxyacyl-CoA dehydrogenase (HOAD) and citrate synthase (CS), in the thorax and abdomen of the unmated 1-day-old adults at 0, 2, 6, 12 and 24 h after tethered flight were assayed by ELISA kit. 【Results】 Based on the accumulative flight duration (AFD), the population of P. xylostella could be divided into three types: short-flight type (AFD≤4.5 h), intermediate-flight type (4.5 h<AFD≤8.5 h) and long-flight type (AFD>8.5 h). No significant differences in tethered flight capacity were observed among the unmated adults of P. xylostella at different day-old and between female and male adults at the same day-old. The accumalative flight duration of the unmated 1-day-old males was significantly lower than that of the 3-6-day-old males. The average flight velocity and accumulative flight distance of the F3 and F20 populations were significantly lower than those of the field population, and the accumalative flight duration and the proportion of long-flight type individuals in F20 decreased significantly as compared to those of the field population. Within the 24-h tethered flight, the triglyceride contents in the thorax and abdomen of the 1-day-old female and male adults gradually increased; the soluble sugar content in the thorax in resting state was lower than that during tethered flight, while that in the abdomen was decreased first and then increased, and reached the lowest value at 6 h after tethered flight. The activities of six key enzymes related to energy metabolisn in the thorax and abdomen of the 1-day-old female and male adults showed similar change trend, gradually increasing with tethered flight duration. Furthermore, the activities of GAPDH, GPD and HOAD were always at high levels, while those of LDH and CS were relatively low. The activity ratio of GAPDH to HOAD was slightly higher than 1.0, and reached the peak at 2 h after tethered flight. 【Conclusion】 P. xylostella adults have strong flight capacity. Their energy utilization mode during flight is a mixed type, whereas the ability to utilize carbohydrates in the initial phase of flight within 2 h is stronger than that to utilize lipids. In the process of flight, both female and male adults are capable of high-speed aerobic metabolism, and also possess a certain capacity for anaerobic metabolism.
    Behaviour rhythm of courtship and mating in Glyphodes caesalis (Lepidoptera: Pyralidae)
    ZHONG Yao-Feng, ZHA Xue-Zong, WANG Zheng, ZHU En-Hang, ZHANG Shao-Hua, WU Gang, LIN Xian-Wu, JI Heng-Qing, MENG Qian-Qian
    2023, 66(8):  1075-1085.  doi:10.16380/j.kcxb.2023.08.008
    Abstract ( 91 )   PDF (11750KB) ( 106 )   　　
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    【Aim】 To investigate the courtship and mating behavior rhythm of the jackfruit borer, Glyphodes caesalis, so as to provide a theoretical basis for the extraction and identification of sex pheromones of this insect, the mechanism of hermaphroditic communication and the cluster trapping technology. 【Methods】 The sex ratio of female to male pupae of G. caesalis was counted, the adult eclosion rates of G. caesalis during the light and dark periods were determined and its courtship and mating behaviors were observed. Moreover, the effects of host (Artocarpus heterophyllus), day-old age of adults and dark period on the mating rate, mating duration and mating frequency of this insect were also determined by proportional pairing test. 【Results】 The average sex ratio of female to male pupae of G. caesalis was 1.06∶1, and the proportion of female pupae was significantly greater than that of male pupae. The peak of eclosion of G. caesalis adults was concentrated in the 2 h before and after the light-dark transition period. The mating of G. caesalis occurred only in the dark period and was facilitated by the presence of the host A. heterophyllus, with the mating rate of 93.33%±2.89% in the fruiting group, significantly higher than that in the fruitless group (71.67%±14.43%). The mating age of adults in the fruiting group and fruitless group ranged from 3-5-day-old and 3-7-day-old, respectively. The mating rate of the 3-day-old adults in the fruiting group was 53.33%±11.55%, which was significantly higher than that in the fruitless group (31.67%±5.77%), while the mating rate of adults in the fruiting and fruitless groups gradually decreased with the increasing of adult age. In the fruiting group, the mating period of adults was mainly concentrated between 0-2 h into the dark period, the peak of mating occurred at 0-0.5 h of the dark period, earlier than that in the fruitless group, and the mating rate was 36.67%±17.56%. However, in the fruitless group, the mating period of adults was mainly concentrated between 0-3.5 h into the dark period, the peak of mating occurred at 1.0-1.5 h of the dark period, and the mating rate was 16.67%±11.55%. The female adults of G. caesalis mated up to 2 times, and the male adults mated up to 4 times, but the proportion of mating female and male adults decreased with the increasing of the mating frequency. The earlier the first mating, the higher the probability of multiple mating. When the first mating of female and male adults occurred at the 3-day-old, they could mate 2 and 4 times, respectively. When the first mating of female and male adults occurred at the 5-day-old, the two sexes had no multiple mating behaviors. 【Conclusion】 G. caesalis can mate multiple times, and the host A. heterophyllus has a facilitating effect on the mating. The mating behavior of this insect is rhythmic, and only occurs in the dark period. The peak of mating occurs at the 3-4-day-old, mostly within 0-2 h of the dark period.
    Effects of cadmium and chlorantraniliprole on the growth and development and detoxification enzyme activities of Ostrinia furnacalis (Lepidoptera: Pyralidae)
    XU Fan-Shu, GUO Xin, CHAI Zheng-Hao, YE Li-Wen, CHENG Dan-Ya, WEI Hong-Yi, CHEN Li-Hui
    2023, 66(8):  1086-1094.  doi:10.16380/j.kcxb.2023.08.009
    Abstract ( 89 )   PDF (1520KB) ( 320 )   　　
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    【Aim】 To clarify the defense mechanism of Ostrinia furnacalis against cadmium and chlorantraniliprole, and to evaluate the cumulative effects of heavy metals and pesticide pollution on insects. 【Methods】 The newly hatched larvae of O. furnacalis were fed with the artificial diet containing 5 mg/kg cadmium, 0.003 mg/kg chlorantraniliprole and 5 mg/kg cadmium+0.003 mg/kg chlorantraniliprole, respectively, and those fed with the normal artificial diet were used as the control. The developmental duration, body weight, adult emergence rate and abnormal pupal rate were recorded, and the activities of detoxification enzymes including glutathione-S-transferase (GST), carboxylesterase (CarE) and acetylcholinesterase (AChE) in O. furnacalis at different developmental stages (3rd instar larva, female and male pupae, and female and male adults) were detected. 【Results】 Cadmium (5 mg/kg), chlorantraniliprole (0.003 mg/kg), and their combined treatment (5 mg/kg cadmium+0.003 mg/kg chlorantraniliprole) had effects on the growth and development of O. furnacalis. In chlorantraniliprole treatment group, the larval duration of O. furnacalis was the longest, significantly prolonged by 7.1 d as compared to that in the control group, and the pupal weight, adult weight and adult emergence rate of O. furnacalis were the lowest, significantly decreased by 9.1 mg, 2.4 mg and 25.5% as compared with those in the control group. In cadmium+chlorantraniliprole treatment group, the larval duration of O. furnacalis was 4.9 d shorter than that in chlorantraniliprole treatment group, and the abnormal pupal rate was the highest, significantly increased by 19.4% as compared to that in the control group. The adult duration of O. furnacalis in cadmium+chlorantraniliprole treatment group was the shortest, significantly reduced by 1.6 d as compared to that in the control group. Cadmium, chlorantraniliprole and cadmium+chlorantraniliprole had effects on the detoxification enzyme activities in O. furnacalis. Compared with the control, cadmium, chlorantraniliprole and cadmium+chlorantraniliprole showed inducing effects on the GST activities in the 3rd instar larvae, female and male pupae and male adults of O. furnacalis, and the GST activities in different developmental stages of O. furnacalis in cadmium+chlorantraniliprole treatment group were significantly higher than those in the other treatment groups and the control group. Compared with the control, cadmium, chlorantraniliprole and cadmium+chlorantraniliprole showed inhibitory effects on the CarE activities in different developmental stages of O. furnacalis, and the cadmium+chlorantraniliprole treatment had the strongest inhibitory effect on the CarE activities in various developmental stages of O. furnacalis. Compared with the control, cadmium, chlorantraniliprole and cadmium+chlorantraniliprole showed inducing effects on the AChE activity in the 3rd instar larvae of O. furnacalis, but had different effects on the AChE activities in the pupae and adults. 【Conclusion】 Cadmium (5 mg/kg), chlorantraniliprole (0.003 mg/kg) and their combined treatment can all affect the growth and development of O. furnacalis, and have different effects on its detoxification enzyme activities.
    Effects of oviposition times and host larval instars on the biological characters of Cotesia ruficrus (Hymenoptera: Braconidae), an indigenous parasitoid of Spodoptera frugiperda (Lepidoptera: Noctuidae)
    HE Peng-Yang, LI Xian, LIU Tong-Xian, ZHANG Shi-Ze
    2023, 66(8):  1095-1104.  doi:10.16380/j.kcxb.2023.08.010
    Abstract ( 122 )   PDF (2253KB) ( 242 )   　　
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    【Aim】 To evaluate the parasitism potential of Cotesia ruficrus, an indigenous parasitic natural enemy, against the larvae of Spodoptera frugiperda, a major invasive agricultural pest. 【Methods】The parasitism preference of the mated 24 h-old female adults of C. ruficrus to the 1st-3rd instar larvae of S. frugiperda was performed by selection test. The developmental duration, numbers of cocoons, eclosion rates, sex ratios (proportions of females), adult longevity and adult size of the offspring of C. ruficrus were determined when its mated 24 h-old female adults parasitized the 1st, 2nd or 3rd instar larvae of S. frugiperda, respectively, by non-selection test. The oviposition times of the mated 24 h-old female adults of C. ruficrus on the 2nd instar larvae of S. frugiperda were determined by the direct observation method, and then the effects of different oviposition times on the developmental duration, number of cocoons, eclosion rate, sex ratio, adult longevity and adult size of the offspring of C. ruficrus were measured. The parasitic functional response of the mated 24 h-old female adults of C. ruficrus to the 2nd instar larvae of S. frugiperda was determined with small-leaf dish method. 【Results】 When the mated 24 h-old female adults of C. ruficrus parasitized the 1st-3rd instar larvae of S. frugiperda, the parasitism rates, egg-larval duration, pupal duration, numbers of cocoons per host, eclosion rates, and proportions of females of C. ruficrus were 34%-54%, 8.7-9.9 d, 3.9-4.1 d, 19.7-41.2 cocoons, 84.4%-92.0% and 31.5%-38.8%, respectively, and the female adult size of the offspring was larger than the males. The female adult longevity of the offspring of C. ruficrus was significantly longer than that of the males when the 1st or 3rd instar larvae of S. frugiperda were parasitized. The oviposition times of the mated 24 h-old female adults of C. ruficrus on the 2nd instar larvae of S. frugiperda had a significant effect on the biological characters of the offspring of C. ruficrus. With the increase of the oviposition times, the male adult longevity of the offspring of C. ruficrus was shortened, and the male adult size of the offspring became smaller. Compared with parasitization once, after the 2nd instar larvae of S. frugiperda were parasitized by the mated 24 h-old female adults of C. ruficrus for three times, the egg-larval duration of the offspring of C. ruficrus was significantly prolonged by 0.7 d, the pupal duration was shortened by 0.4 d, the number of cocoons per host significantly increased by 25 and the proportion of females significantly decreased by 58.8%. The parasitic functional response of the mated 24 h-old female adults of C. ruficrus to the 2nd instar larvae of S. frugiperda was Holling Ⅱ type, the daily maximum parasitic number was 17.5, the instantaneous attack rate was 0.043 and the average handling time was 1.368. 【Conclusion】 This study evaluated for the first time the biological control potential of C. ruficrus against S. frugiperda larvae, and indicated that the parasitoid was an effective native natural enemy of S. frugiperda, providing technical reserves and theoretical basis for further utilizing local natural enemies to control invasive pests.
    Observation of the sensilla on the adult antennae of Cotesia ruficrus (Hymenoptera: Braconidae), a parasitoid of Spodoptera frugiperda (Lepidoptera: Noctuidae), under scanning electron microscope
    WANG Wen-Wen, HE Peng-Yang, LIU Tong-Xian, JING Xiang-Feng, ZHANG Shi-Ze
    2023, 66(8):  1105-1116.  doi:10.16380/j.kcxb.2023.08.011
    Abstract ( 131 )   PDF (41159KB) ( 135 )   　　
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    【Aim】 To clarify the types, morphology, quantity and distribution of sensilla on the female and male adult antennae of Cotesia ruficrus, an indigenous parasitic natural enemy against Spodoptera frugiperda, a major invasive agricultural pest, and provide theoretical support for exploring the function and olfactory mechanism of various types of sensilla of C. ruficrus.【Methods】 The sensilla on female and male adult antennae of C. ruficrus were observed with scanning electron microscope. 【Results】 The subsegments of antennal flagellum of the male adult of C. ruficrus are long moniliform, and the distal 5 segments of the antennae of female adults are short moniliform. The total length of the male antennae is significantly longer than that of the female. Eleven types of sensilla including Böhm’s bristles, sensilla trichodea, sensilla placodea, sensilla basiconica, sensilla chaetica, sensilla coeloconica, sensilla campaniformia, sensilla squamous, sensilla gemmiformia, sensilla cavity and sensilla cylindric, and smell pores were found on female and male adult antenna. Among them, sensilla trichodea, sensilla placodea and sensilla basiconica have two subtypes. Sensilla trichodea and sensilla placodea are the main sensilla on the antennae of C. ruficrus, with a wide distribution and a large number. Sensilla cavity are only distributed in pairs on the pedicel, and sensilla cylindric were only found on the flagellum of male adult. Sensilla gemmiformia were found for the first time in Braconidae.【Conclusion】We identified eleven types of antennal sensilla in female and male adults of C. ruficrus, more than those in other known braconid species, and sensilla gemmiformia were found for the first time in braconid species, speculating that they may play an important role in host positioning and searching for spouses.
    REVIEW ARTICLES
    Control of common insect pests in ancient buildings, murals and earthen sites: Research status and prospects
    HU Yu-Lan, QIN Yue, ZHANG Bing-Jian
    2023, 66(8):  1117-1127.  doi:10.16380/j.kcxb.2023.08.012
    Abstract ( 98 )   PDF (3575KB) ( 357 )   　　
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     Unmovable cultural relics are important physical materials that reflect the development of social productivity and social life in the past. They are important research objects for cultural relics, with extremely high historical, artistic and scientific values. Unmovable cultural relics suffer from various deterioration effects for being outdoors. Biodeterioration caused by pests is one of the important reasons for cultural relics damage. Among unmovable cultural relics, ancient buildings, murals and earthen sites are particularly affected by insect pests. According to the classification of cultural relics, we expounded on the main types and mechanisms of insect pests in ancient buildings, murals and earthen sites, and summarized the current methods of pest control in these cultural relics in this article. Physical and chemical control methods are traditionally used to prevent and control pests in cultural relics. The chemical methods are rapid and highly effective ways to kill insects, but chemical agents have brought great pollution to the ecological environment, and the vulnerability of cultural relics restricts the use of chemical insecticides. At present, many long-acting and environment-friendly green insecticides have greatly improved traditional chemical methods. In addition, biological control methods that use biological natural enemies or parasitic organisms to control pests not only have small impacts on the ecosystem but also have a long-lasting effect, which is a hotspot in research on new pest control. However, whether the new species used to control the pests will do harm to cultural relics needs to be further studied. Pest control of cultural relics is a cross-research field, and the methods in architecture, agriculture and other fields have great enlightening significance and reference value. Finally, we discussed and prospected the current situation of common pest control research of unmovable cultural relics, hoping to provide a reference for the research of pest control in cultural relics.
    Research advances in occurrence characteristics and monitoring and control strategies of Solenopsis invicta (Hymenoptera: Formicidae) in forests, grasslands, wetlands and urban green spaces
    DU Cheng-Ju, WANG Lei, LU Yong-Yue, JIA Cai-Juan, LIN Xu-Ping, XU Shao-Chang, WEN Xiu-Jun, WANG Cai
    2023, 66(8):  1128-1138.  doi:10.16380/j.kcxb.2023.08.013
    Abstract ( 98 )   PDF (1546KB) ( 440 )   　　
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     The red imported fire ant, Solenopsis invicta, is a primary invasive pest in China. Currently, scientific researches, control strategies and policy regulations regarding S. invicta mainly focus on the filed of agriculture in China. Although S. invicta is also widely distributed in forests, grasslands, wetlands and urban green spaces and has caused huge damage, the occurrence characteristics and control strategies of S. invicta in these areas are largely overlooked. The occurence of S. invicta is closely associated with human disturbances such as felling, burning and soil turning, and natural factors such as biodiversity, forest canopy density and soil bareness. Due to the low levels of biological diversity and forest canopy density and high levels of human disturbances, there is a high risk of S. invicta invasion in plantation forests and adjacent areas. In natural forests, S. invicta is usually distributed in forest edges and windows, as well as burned areas where the sunlight can directly irradiate. Moreover, nurseries and urban green spaces have a high risk of S. invicta invasion because of large areas of bare soil and high levels of human activities. In areas with high levels of human activities, including plantation forests, nurseries and urban green spaces, S. invicta mainly threatens human health and infrastructure, and directly or indirectly damages trees. In addition, the invasion of S. invicta significantly decreases the abundance and diversity of arthropods in habitats and poses significant threats to wildlife in natural reserves and wetlands. Although it has been reported that S. invicta contributes to promoting seed migration and enhancing soil nutrient circulation under certain conditions, its harmful impacts far exceed its potential beneficial effects. Quarantine, monitoring and control are three important aspects to prevent S. invicta invasion in forestry. Wood, seedlings with soil, and turf are the main objects that may carry S. invicta and need to be quarantined, and fumigation can effectively eliminate S. invicta. Baiting and trapping are the main methods to monitor S. invicta. Recently, some new technologies, including remote sensing and radar technology, also have been developed to monitor S. invicta in grasslands and urban green spaces. Although chemical control is the most predominant control strategy for S. invicta, the use of highly toxic, broad spectrum and hardly degradable insecticides may negatively affect non-target organisms in natural reserves and wetlands. Therefore, it is essential to develop environmentally friendly agents and methods to control S. invicta.
    CONTENTS
    Contents of Vol. 66 Issue 8
    2023, 66(8):  1139-1139. 
    Abstract ( 39 )   PDF (502KB) ( 89 )   　　
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