Acta Entomologica Sinica

Role of the small heat shock protein gene HaHSP19.8 in response to stress in Helicoverpa armigera (Lepidoptera: Noctuidae)

WEI Ji-Zhen, WANG Kai, LIU Shao-Kai, LIU Xiao-Guang, LIANG Ge-Mei, DU Meng-Fang, AN Shi-Heng

2020, 63(8): 913-923. doi:10.16380/j.kcxb.2020.08.001

Abstract ( 108 )

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【Aim】 Small heat shock proteins (sHSPs) play important roles in resisting external environmental pressure in insects. This study aims to explore the functions of a small heat shock protein gene, sHSP19.8, in the growth and development of the cotton bollworm, Helicoverpa armigera, and its role in response to high temperature stress and insecticidal protein, so as to provide a foundation for further exploring its action mechanisms and controlling the cotton bollworm. 【Methods】 The full-length cDNA sequence of sHSP19.8 gene was cloned from H. armigera by RCR and RACE, and analyzed by bioinformatics software. The expression levels of sHSP19.8 gene in the 5th instar larvae of the Cry1Ac-susceptible cotton bollworm exposed to 40℃ for 1 h and 2 h and fed with the artificial diet containing 30 μg/mL Cry1Ac for 1 h and 2 h, respectively, were detected by qRT-PCR. Meanwhile, the expression patterns of sHSP19.8 gene in different developmental stages (1st-5th instar larva, pupa and adult) and tissues (foregut, midgut, hindgut, Malpighian tubules and cuticle) of the 5th instar larvae of the Cry1Ac-susceptible and resistant cotton bollworm were also assayed by qRT-PCR. 【Results】 The fulllength cDNA sequence of sHSP19.8 from H. armigera was obtained and named HaHSP19.8 (GenBank accession no.: XP_021195228.1). It is 608 bp in length with an open reading frame (ORF) of 528 bp, encoding 175 amino acids. The encoded protein has the typical α-crystallin domain (ACD). After induction by high temperature of 40℃ and 30 μg/mL Cry1Ac, HaHSP19.8 showed over-expression in the 5th instar larvae of the Cry1Ac-susceptible cotton bollworm. HaHSP19.8 was ubiquitously expressed in all the examined developmental stages and tissues of the 5th instar larvae of the Cry1Ac-susceptible cotton bollworm, with relatively higher expression levels in adults and the 5th instar larvae, and the cuticle, Malpighian tubules and midgut of the 5th instar larvae. However, HaHSP19.8 showed lower expression levels in all the examined developmental stages and tissues of the 5th instar larvae of the Cry1Ac-resistant cotton bollworm than in those of the Cry1Ac-susceptible cotton bollworm. 【Conclusion】 The results suggest that HaHSP19.8 may participate in the growth and development of the cotton bollworm to resist the environment stress, and may be involved in the resistance to Cry1Ac.

Role of fruitless in courtship and mating behaviors in Bactrocera dorsalis (Diptera: Tephritidae)

CHEN Yao-Yao, GU Feng, ZHONG Guo-Hua, YI Xin

2020, 63(8): 924-931. doi:10.16380/j.kcxb.2020.08.002

Abstract ( 68 )

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【Aim】 fruitless (fru) is the key gene for courtship and mating behaviors in insects, but its specific role in Bactrocera dorsalis is still unclear. The aim of this study is to characterize the role of fru in courtship and mating behaviors in B. dorsalis and to further clarify its biological significance. 【Methods】 Primers were designed based on the fru sequence of B. dorsalis from NCBI, the full-length cDNA of fru gene was cloned from the head of the mated 10-day-old adults of B. dorsalis, and the structural domain of its encoded protein was predicted. The variations of gene expression levels in B. dorsalis adults before and after mating were analyzed by real-time fluorescent quantitative PCR (RT-qPCR). The fru dsRNA was synthesized, and injected into the abdomen of the 9-day-old adults. The relative expression level of fru was examined at 48 and 72 h after injection. At 72 h after injection, the courtship and mating behaviors including the mating frequency and duration were examined. 【Results】 The full-length cDNA of B. dorsalis fru obtained by cloning is 2 865 bp in length, encoding 954 amino acids with the predicted molecular weight of 104.1 kD and pI of 6.01. The encoded protein has unique domains including one BTB domain and two zinc finger domains. The RT-qPCR results revealed that the expression level of fru in the head of male adults of B. dorsalis was significantly higher after mating than before mating. B. dorsalis male adults in the RNAi group injected with dsfru engaged significantly longer time (25-35 min longer) in the courtship behavior and had the mating frequency decreased by 17%-22% as compared to the male adults in the blank control group (injected with DEPC water) and the negative control group (injected with dsGFP), suggesting that fru plays important roles in regulating courtship and mating behaviors of male B. dorsalis. 【Conclusion】 The results of this study provide a theoretical basis for clarifying the role of fru in the non-model insect B. dorsalis and further studying courtship and mating behaviors in B. dorsalis.

Transcriptomic analysis of diapause-associated genes in Exorista civilis (Diptera: Tachinidae)

ZHANG Bo, HAN Hai-Bin, XU Lin-Bo, GAO Shu-Jing, GAN Lin, YUE Fang-Zheng, LIU Ai-Ping

2020, 63(8): 932-940. doi:10.16380/j.kcxb.2020.08.003

Abstract ( 55 )

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【Aim】 This study aims to explore the crucial associated genes and metabolic pathways that regulate the diapause of Exorista civilis, and to provide a theoretical basis for clarifying the molecular mechanism of diapause of this species at the transcriptome level. 【Methods】 The Illumina HiSeq^TM 2000 platform was used to perform transcriptome sequencing and bioinformatics analysis of the non-diapause and diapause pupae of E. civilis. KAAS (KEGG Automatic Annotation Server) online pathway comparison tool was used to analyze the KEGG pathway enrichment of the differentially expressed genes that meet the conditions of padj<0.05 and fold change≥32 or padj<0.05 and fold change≤1/32. 【Results】 According to the sequencing results, a total of 58 050 unigenes were obtained. There were 454 diapause-associated genes (DAGs) with the difference of more than 32-fold changes. Among them, 406 DAGs were up-regulated and involved in a total of 134 pathways, including oxidative phosphorylation, citrate cycle and other important pathways, and 48 DAGs were down-regulated and related to 32 pathways. KEGG enriched pathways revealed that the DAGs are mainly involved in signal transduction, endocrine system and carbohydrate metabolism. 【Conclusion】 The transcriptome data of E. civilis obtained in this study have revealed the important metabolic pathways and associated genes in diapause regulation in E.civilis.

Cloning and expression analysis of cytochrome P450 genes CYP332A19 and CYP337B19 in the codling moth, Cydia pomonella(Lepidoptera: Tortricidae)

CHEN Gao-Man, CHEN Zhan-Bo, GE Hui, YANG Xue-Qing, WANG Xiao-Qi

2020, 63(8): 941-951. doi:10.16380/j.kcxb.2020.08.004

Abstract ( 69 )

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【Aim】 This study aims to clone the sequences of two cytochrome P450 genes CYP332A19 and CYP337B19 from the codling moth, Cydia pomonella, and to analyze their structure properties and expression profiles, so as to further understand the roles of the two genes in the detoxification of plant secondary substances and to provide evidence for further functional research. 【Methods】 The cytochrome P450 gene cDNA sequences were searched from the transcriptome database of C. pomonella by local BLSTA, and the coding regions of the target genes were cloned using RT-PCR. Bioinformatics software was used to analyze the sequence characteristics and phylogenetic relationship of the target genes with P450 genes of other related species. RT-qPCR was employed to determine the expression patterns of the CYP450 genes in different developmental stages (egg, 1st-5th instar larva, pupa, and adult), various tissues (head, epidermis, fat body, midgut, and Malpighian tubules) of the 4th instar larvae, and the 4th instar larvae of C. pomonella fed with artificial diets supplemented with 0.1% coumarin and 0.5% quercetin, respectively, for 2 d. 【Results】 The full-length cDNA sequences of CYP450 genes CYP332A19 (GenBank accession no.: MF574708) and CYP337B19 (GenBank accession no.: MF574697) were cloned, with an open reading frame (ORF) of 1 518 bp and 1 491 bp in length, respectively, encoding 505 and 496 amino acids, respectively. The molecular mass of CYP332A19 and CYP337B19 is 58.586 and 57.734 kD, respectively, and their theoretical isoelectric points are 8.99 and 7.61, respectively. Domain analysis showed that both CYP332A19 and CYP337B19 contain five conserved regions of CYP450 genes, including the heme binding domain. Phylogenetic analysis indicated that CYP332A19 and other CYP332A genes such as CYP332A9 from Epighyas postvittana were clustered together, while CYP337B19 and CYP337B genes such as CYP337B12 from Cnaphalocrocis medinalis and CYP337B11 from Zygaena filipendulae were gathered in another branch. The RT-qPCR results showed that the mRNA levels of CYP332A19 and CYP337B19 in the larval stage of C. pomonella were higher than those in the egg stage. Moreover, CYP332A19 and CYP337B19 had the highest expression levels in the fat body and midgut of the 4th instar larva, respectively. The relative expression levels of CYP332A19 and CYP337B19 in the 4th instar larvae fed on the artificial diets containing 0.1% coumarin and 0.5% quercetin, respectively, for 2 d were significantly higher than those in the control group (fed on the artificial diet containing 2% DMSO). 【Conclusion】 CYP332A19 and CYP337B19 show the highest expression level in the fat body and midgut of C. pomonella larva, respectively, and are upregulated in the larvae fed with the artificial diets containing coumarin and quercetin, suggesting that the two genes might play a critical role in the detoxification of xenobiotics. The results of this study are helpful for understanding the detoxification mechanism to plant secondary metabolites in the codling moth and provide new ideas for the control of the moth.

Prokaryotic expression, purification and enzymatic characterization of SeGrx1 of the beet armyworm, Spodoptera exigua(Lepidoptera: Noctuidae)

YANG Fu-Lai, ZHAO Zhen-Zhen, WANG Yue-Hua, ZHANG La, ZHANG Yan-Ning, MAO Lian-Gang, JIANG Hong-Yun

2020, 63(8): 952-960. doi:10.16380/j.kcxb.2020.08.005

Abstract ( 48 )

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【Aim】 Glutardoxin (Grx) is a thiol-dependent antioxidant enzyme in organisms and plays roles in many important life activities including biological oxidative stress and cell apoptosis. This study aims to analyze the gene sequence of SeGrx1 of the beet armyworm, Spodoptera exigua, and its enzyme-catalyzed reaction characteristics, so as to lay a foundation for revealing the function of SeGrx1 in S. exigua. 【Methods】 Based on the previously obtained transcriptome data of S. exigua, the full-length cDNA of Grx1 gene was cloned by RACE-PCR. The ORF of the gene was linked to the prokaryotic expression vector pET-16b and expressed in Escherichia coli BL21 induced with IPTG. The fusion protein was purified by Ni-NTA chromatographic column and Superdex75/200 molecular sieve. The enzymatic activity and catalytic kinetics of the purified SeGrx1 were detected by fluorescence microplate reader. 【Results】 The full-length cDNA of SeGrx1 (GenBank accession no.: MK318813) of S. exigua is 738 bp in length, with an open reading frame (ORF) of 351 bp flanked by a 5′ non-coding region of 40 bp and a 3′ non-coding region of 347 bp. Bioinformatics and structure analysis showed that SeGrx1 consists of 116 amino acids, with the predicted molecular weight of 12.57 kD. SeGrx1 belongs to dithiol glutaredoxin characterized by including a CPYC active site. SeGrx1 is composed of four parallel and antiparallel β-strands in the center, which are surrounded by five α-helixes. The recombinant plasmid pET-16b-SeGrx1 was successfully constructed and highly expressed in E. coli. The target protein SeGrx1 with the purity of more than 95% was obtained by optimizing the induction and purification conditions. With hGrx1 of human as the standard, the specific activity of the purified SeGrx1 was 0.577 U/mg pro, the V_max value was 20.5 U/mg pro, and the Km value was 14.3 nmol/L. 【Conclusion】 In this study SeGrx1 of S. exigua was successfully expressed in vitro, and its enzymatic kinetic parameters were obtained, providing a foundation for further exploring the biological function of this protein and its application in pest control.

Role of the cytochrome P450 gene AsCYP6Z2 in the maintenance of deltamethrin resistance in Anopheles sinensis (Diptera: Culicidae)

HAN Bao-Zhu, CHE Lin-Rong, CHEN Xiao-Jie, YAN Zhen-Tian, QIAO Liang, CHEN Bin

2020, 63(8): 961-972. doi:10.16380/j.kcxb.2020.08.006

Abstract ( 72 )

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【Aim】 To investigate whether the cytochrome P450 gene AsCYP6Z2 is related to the pyrethroid resistance in Anopheles sinensis. 【Methods】 The coding region of the AsCYP6Z2 gene of An. sinensis was cloned. The expression profiles of this gene in different developmental stages of female mosquitoes of the deltamethrinsusceptible strain (WX-LS) and resistant strain (YN-LR) of An. sinensis and its expression profiles in different segments of female pupae of WX-LS were detected by real-time quantitative PCR (qPCR). The posterior segment of female pupal abdomen was incubated with 25 mg/mL deltamethrin solution and acetone (control), respectively, and the consequent expression response of CYP6Z2 between the deltamethrin treatment group and the acetone control group was compared by qPCR. After injection with dsAsCYP6Z2 (the RNAi group) and dsEGFP (the control group) into the 10 h old pupa, the difference in the expression level of AsCYP6Z2 between the RNAi group and the control group was compared by qPCR, the knockout rate of female adults after exposure to 0.05% deltamethrin film in 1 h and the mortality of female adults after exposure to 0.05% deltamethrin film for 1 h and then recovered for 24 h in the RNAi group and the control group were determined by bioassay method. Furthermore, the amino acid residues interacting with deltamethrin were predicted by using molecular docking. 【Results】 The coding region of AsCYP6Z2 gene (GenBank accession no.: MT840336) was cloned, and its ORF is 1 251 bp in length, encoding 416 amino acids without signal peptide and transmembrane domain. Developmental expression profiles revealed that AsCYP6Z2 gene was highly expressed in the period from 30 h old pupa to 3 h old adult, and its expression level in the resistant strain was significantly higher than that in the susceptible strain. Tissue expression profiles revealed that AsCYP6Z2 was highly expressed in the posterior segments of abdomen, followed by in the anterior segments of abdomen, throax and head. At 12 h and 24 h after incubation of the posterior segments of female pupal abdomen with 25 mg/mL deltamethrin solution, the expression level of AsCYP6Z2 increased by 4-fold and 13-fold as compared with the control (incubated with acetone), respectively. After RNAi of AsCYP6Z2, the expression level of AsCYP6Z2 gene in the RNAi group decreased by about 80% compared with the control group (dsEGFP injection group). When the female adults were exposed to 0.05% deltamethrin film in 1 h, the individuals in the RNAi group showed significant knockdown phenomenon about 20 min in advance, and the knockdown rate was significantly higher than that in the control group. In addition, the mortality of individuals in the RNAi group after exposure to 0.05% deltamethrin film for 1 h and then recovered for 24 h increased by 17% compared to the control group, indicating that silencing the AsCYP6Z2 gene results in a significant increase in mosquito sensitivity to deltamethrin. The molecular docking between deltamethrin and the predicted AsCYP6Z2 protein showed that deltamethrin can enter the binding pocket of AsCYP6Z2 protein, forming a Pi-sulfide interaction with Cys-155 and generating more stable hydrogen bonds. The side chain can also form a stable hydrophobic interaction network with Ala-165, Val-72, Leu-76, Leu-82, Ala-24 and other amino acid residues of AsCYP6Z2. 【Conclusion】 The results indicate that the AsCYP6Z2 gene is involved in maintaining the deltamethrin resistance phenotype of An. sinensis, laying a foundation for further exploring the molecular mechanism of AsCYP6Z2 gene in the metabolism of pyrethroid insecticides.

Effects of Aleurocanthus spiniferus (Hemiptera: Aleyrodidae) infestation on the contents of biochemical components and the activities of antioxidant enzymes in the leaves of Huangjinya tea

LI Cheng-Jin, SONG Chang-Yuan, WANG Peng, CHEN Zhen-Zhen, XU Yong-Yu

2020, 63(8): 973-980. doi:10.16380/j.kcxb.2020.08.007

Abstract ( 49 )

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【Aim】 To clarify the influence of Aleurocanthus spiniferus infestation on the contents of biochemical substances and activities of antioxidant enzymes in tea leaves, so as to provide references for acurate, safe, efficient and green control of A. spiniferus to improve tea quality. 【Methods】 The contents of biochemical components including tea polyphenol, soluble sugars, free amino acids, caffeine and catechin and the activities of three antioxidant enzymes (SOD, POD and CAT) in the 3rd leaves of Huangjinya tea (Camellia sinensis cv. Huangjinya) damaged by A. spiniferus at different levels were determined. 【Results】 With the increase of the damage level of A. spiniferus, the content of tea polyphenol in the 3rd leaves of Huangjinya tea decreased significantly and was the lowest (18.82%±0.21%) when the damage level was IV, while the contents of the free amino acids, caffeine, soluble sugars and catechin did not change significantly. The activities of POD and CAT in the 3rd leaves of Huangjinya tea firstly increased significantly and then decreased as the damage level increased, and were the highest at the damage level I, being 57.14±3.98 and 28.05±0.40 U/mg pro, respectively. The SOD activity decreased significantly with the increase of the damage level, and was the lowest (442.73±10.54 U/mg pro) when the damage level was IV. 【Conclusion】 There is no significant change in the contents of caffeine and catechins related to insect resistance and the contents of free amino acids and soluble sugars related to stress compensation in the leaves of Huangjinya tea damaged by A. spiniferus. However, the content of tea polyphenol decreases significantly, and the activities of the three antioxidant enzymes increase firstly and then decrease significantly as the damage level increases, suggesting that the resistance of Huangjinya tea to A. spiniferus infestation is quite low and the scientific management of A. spiniferus on Huangjinya tea needs to be strengthened.

EAG and behavioral responses of Scythropus yasumatsui (Coleoptera: Curculionidae) to volatiles from the common jujube (Zizyphus jujuba)

YAN Xiong-Fei, LIU Yong-Hua, WANG Ya-Wen, LI Gang, JING Rui, YANG Ya-Jie

2020, 63(8): 981-991. doi:10.16380/j.kcxb.2020.08.008

Abstract ( 84 )

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【Aim】 Scythropus yasumatsui is an important pest of the common jujube (Zizyphus jujuba) and has broken out in Shaanxi and Shanxi provinces in recent years, causing considerable economic and ecological loss. The purpose of this study is to demonstrate the role of jujube volatiles in chemical communication in S. yasumatsui adults, so as to provide basic data for the development of botanical attractants for weelives. 【Methods】 The volatiles from buds of five common jujube cultivars (Muzao, Goutouzao, Zanhuangzao, Junzao, and Suanzao) were collected by headspace absorption device and then identified and quantified with gas chromatography and mass spectrometry (GC-MS). The EAG and behavioral responses of S. yasumatsui adults to 17 volatile compounds of the common jujube were assayed with electroantennogram (EAG) apparatus and Y-tube olfactometer, respectively. 【Results】 A total of 26 volatile compounds of six groups, including 9 terpenes, 6 esters, 4 alcohols, 4 alkanes, 2 aldehydes and 1 phenol, were indentified from buds of five common jujube cultivars. The volatile compounds and their contents were different in buds of different common jujube cultivars. The EAG test results showed that there were significant differences in the relative EAG response value in S. yasumatsui adults to the tested 17 volatile compounds from the common jujube. The EAG responses of S. yasumatsui adults to D-limonene, n-tridecane, n-tetradecane, n-pentadecane, nonaldehyde, methyl hexadecanoate and methyl oleate were strong. With the increase of the concentration of volatile compounds ranging from 0.1 μg/μL to 100 μg/μL, the relative EAG response values in female and male adults increased first and then decreased. The highest EAG responses occurred at the volatile concentration of 50 μg/μL. The EAG values of female adults to 50 μg/μL of methyl hexadecanoate and nonaldehyde were 3.84 and 3.67, respectively, and those of male adults to these two compounds were 3.47 and 3.21, respectively. At the concentration of 50 μg/μL, methyl hexadecanoate and nonaldehyde elicited significantly higher EAG response of S. yasumatsui adults than other volatile compounds. Behavioral response tests showed that both female and male adults of S. yasumatsui showed obvious taxis to nonaldehyde and methyl hexadecanoate with the selection rate higher than 65%, male adults also showed significant taxis to n-pentadecane, and female and male adults showed no significant taxis to the other volatile compounds tested. 【Conclusion】 Nonaldehyde and methyl hexadecanoate are attractive to both female and male adults of S. yasumatsui, while n-pentadecane is attractive only to male adults. The results suggest that nonaldehyde and methyl hexadecanoate may account for the preference of S. yasumatsui to Z. jujuba.

Effects of feeding and mating on the flight capacity of Agrilus mali (Coleoptera: Buprestidae)

MA Zhi-Long, PENG Bin, CADDEY Kader, ADIL Sattar, ZHANG Yuan-Ming

2020, 63(8): 992-998. doi:10.16380/j.kcxb.2020.08.009

Abstract ( 58 )

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【Aim】 Agrilus mali is a burrowing pest that can wreak havoc on apple trees. The study aims to determine the flight dispersion capability of A. mali and the key factors affecting its flight capability. 【Methods】 The flight capabilities of different day-old male and female adults of A. mali were measured by SUN-FL intelligent flight grinding system, and the effects of feeding and mating conditions on their flight performance were also evaluated. 【Results】 The flight capability of A. mali adults increased and then declined with the increase of age. The newly-emerged adults had the lowest flight capacity, and the 11-day-old adults had the strongest flight capability. Females had a greater flight capacity than males. The maximum flight distance of female and male adults within 24 h was 0.4165 and 0.3559 km, the maximum flight duration was 0.4582 and 0.4873 h, and the maximum flight speeds were 2.4639 and 1.8561 km/h, respectively. The average flight distance and duration of the 3-day-old female adults with feeding were 0.047 km and 0.048 h, respectively, and those of males were 0.044 km and 0.042 h, respectively, while the average flight distance and duration of the 3-day-old female adults without feeding were only 0.016 km and 0.013 h, and those of males were only 0.013 km and 0.012 h, respectively. Mating had different effects on the flight capacities of female and male adults. The flight capacity of the mated females was better than that of the unmated females. However, the flight capacity of the mated males was lower than that of the unmated males. 【Conclusion】 The flight capacity of A. mali adults is heavily dependent on their age. Feeding can significantly improve the flight capacities of both male and female adults of A. mali, and mating can significantly improve the flight capacity of female adults.

Host preferences and control effects of three common rice field dryinids on hemipteran pests

HE Yu-Ting, HE Jia-Chun, WEI Qi, LAI Feng-Xiang, YANG Zhong-Xia, FU Qiang

2020, 63(8): 999-1009. doi:10.16380/j.kcxb.2020.08.010

Abstract ( 69 )

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【Aim】 This study aims at exploring the host preferences and control effects of three common rice field dryinids (Echthrodelphax fairchildii, Gonatopus flavifemur and Haplogonatopus apicalis) on hemipteran pests. 【Methods】 Under the non-choice conditions, Nilaparvata lugens, Sogatella furcifera, Laodelphax striatellus, Nephotettix cincticeps and Nilaparvata muiri were used as hosts for the three dryinids, E. fairchildii, G. flavifemurand H. apicalis, to observe their host-feeding, parasitism activities and offspring development. And the selectivity of the three dryinids on planthoppers was also observed under the choice conditions. On the basis of above tests, the suitable host for each of the three dryinids was evaluated. The suitable hosts were used to study the longevity, host-feeding and parasitism activities for evaluating the control effects of these three dryinids. 【Results】 E. fairchildii could feed on and parasitize N. lugens, L. striatellus, S. furcifera and N. muiri, and the first three planthoppers were more suitable hosts than N. muiri, while N. cincticeps could not be fed upon or parasitized by E. fairchildii. G. flavifemur could feed on and parasitize four species of planthoppers: N. lugens and L. striatellus were highly adaptable hosts for G. flavifemur followed by S. furcifera and then N. muiri. N. cincticeps could be fed upon but not parasitized by G. flavifemur. For H. apicalis, S. furcifera was the most suitable host followed by L. striatellus, while the other three hosts could only be fed on but not parasitized by H. apicalis successfully. On the suitable hosts, H. apicalis females had the longest longevity and the highest total numbers of planthoppers fed upon and parasitized, then G. flavifemur, and finally E. fairchildii, and there was a slight fluctuation in the diurnal variations of host-feeding and parasitism amounts of the three dryinids. 【Conclusion】 E. fairchildii prefers to parasitize N. lugens, L. striatellus and S. furcifera, but its control effect is the lowest. G. flavifemur prefers to parasitize N. lugens and L. striatellus, and it has a medium control effect. H. apicalis prefers to parasitize S. furcifera with the best control effect.

Puparium color variation of Lucilia sericata (Diptera: Calliphoridae) and its significance for the estimation of the postmortem interval

WANG He, TANG Chao, QI Li-Li, DONG Chun-Nan, SONG Zhao-Yu, REN Xiao-Peng

2020, 63(8): 1010-1015. doi:10.16380/j.kcxb.2020.08.011

Abstract ( 29 )

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【Aim】 This study aims to examine the changing trend of puparium color of a common necrophagous fly (Lucilia sericata) under different constant temperatures and to prepare the standard color plates based on the RGB values of puparium, so as to provide a scientific support for the estimation of the postmortem interval (PMI) in forensic medicine. 【Methods】 Ten pupae of L. sericata were sampled at 12 h intervals from prepupa to emergence under different constant temperatures (16℃, 20℃, 24℃, 28℃ and 32℃). The variation of puparium color at all the observed time points in the pupal stage of L. sericata was observed and photographed. The corresponding RGB values of puparium color were collected and analyzed by digital image processing system to prepare the standard color plates. Multivariate regression analysis was employed for fitting the relationship between the developmental time of pupa and the R value of the RGB values of puparium color by R software. 【Results】 The puparium color of L. sericata gradually deepened with the developmental time under different constant temperatures, and obvious changes were observed at the beginning and final time of the pupal stage. Based on the RGB values at different developmental time, five standard color plates of L. sericata puparium were prepared corresponding to different constant temperatures. 【Conclusion】 At the crime scene, the standard color plates of puparium obtained in this study can be used to preliminarily estimate the pupal stage through visual comparison as an auxiliary method. Based on this estimation, the PMI can be deduced.

Phylogeny of hydradephagan water beetles (Coleoptera: Adephaga) inferred with mitochondrial genome sequences

TIAN Tian, YUAN Huan, CHEN Bin

2020, 63(8): 1016-1027. doi:10.16380/j.kcxb.2020.08.012

Abstract ( 64 )

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【Aim】 To clarify the general features of mitochondrial genomes of hydradephagan water beetles, and to analyze the phylogenetic relationship of hydradephagan water beetles based on the mitochondrial genome sequences. 【Methods】 Based on the Illumina HiSeq X Ten sequencing technology, we sequenced and annotated the complete mitochondrial genomes of Dineutus mellyi and Eretes sticticus, and predicted the secondary structures of tRNA genes. Combined with the published mitochondrial genomes of 17 species of hydradephagan water beetles, comparative genomics analyses including the AT content, codon usage bias, and selection pressure were performed on the mitochondrial protein-coding genes (PCGs) of the total 19 species. Based on the amino acid dataset and nucleotide dataset of 13 PCGs, the phylogenetic relationships of hydradephagan water beetles were reconstructed by using maximum likelihood (ML) and Bayesian (BI) methods, respectively, and the systematic position of Noteridae and Meruidae was further evaluated by FcLM analysis. 【Results】 The mitochondrial genomes of D. mellyi and E. sticticus are 16 123 bp (GenBank accession no.： MN781126) and 16 196 bp (GenBank accession no.: MN781132) in length, respectively. Each mitochondrial genome contains 13 PCGs, 22 tRNA genes, 2 rRNA genes and a D-loop region (control region). Within the 19 species of hydradephagan water beetles, the nucleotide composition biases show a higher A+T content, and the codon use bias analysis also found that there is a serious bias towards using AT-rich codons. The evolutionary rates of the 13 protein-coding genes showed a purifying selection. The phylogenetic relationship of hydradephagan water beetles based on the amino acid sequences of the 13 PCGs was: (Gyrinidae+(Haliplidae+((Aspidytidae+(Amphizoidae+Dytiscidae))+(Hygrobiidae+(Meruidae+Noteridae))))). 【Conclusion】 Our results indicate that Gyrinidae is the base group of hydradephagan water beetles, followed by Haliplidae and Dytiscoidea, Noteridae and Meruidae form a sister-group branch within Dytiscoidea, and a closer relationship exists between Amphizoidae and Dytiscidae.

Sequencing and analysis of the complete mitochondrial genome of Zele chlorophthalmus (Hymenoptera: Braconidae)

WANG Dan-Yang, WANG Yu-Tong, YU Liang-Bin, HAN Hai-Bin, XU Lin-Bo, CUI Yan-Wei, KANG Ai-Guo, PANG Hong-Yan

2020, 63(8): 1028-1038. doi:10.16380/j.kcxb.2020.08.013

Abstract ( 58 )

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【Aim】 This study aims to sequence and analyze the complete mitochondrial genome of Zele chlorophthalmus, and to explore the molecular phylogenetic relationship of some groups within Braconidae. 【Methods】 Using Illumina MiSeq sequencing technique, the mitochondrial genome of Z. chlorophthalmus was sequenced, the genome sequences were assembled, annotated and characterized, and then the general features and base composition of the mitochondrial genome were analyzed. To analyze the phylogenetic relationships of Z. chlorophthalmus and other species of Braconidae, the phylogenetic trees of 22 Braconidae species based on mitochondrial COX1 gene sequences were constructed by using maximun likelihood (ML) and neighbor-joining (NJ) methods. 【Results】 The mitochondrial genome of Z. chlorophthalmus (GenBank accession no.: MG822749) is 16 661 bp in length, and contains 37 genes including 13 protein-coding genes (PCGs), 22 tRNA genes and 2 ribosomal RNA genes, and one control region (CR). The mitochondrial genome has a clear bias in nucleotide composition with a positive AT-skew and a negative GC-skew, with the A+T content of 82.83%. The mitochondrial gene arrangement of Z. chlorophthalmus is not completely consistent with that of the putative ancestral sequence of insects, and there are seven gene rearrangements in its tRNA genes. All the 13 PCCs start with an ATN initiation codon and terminate with a TAA stop condon. All the predicted tRNA genes show the classic clover-leaf secondary structure, except that tRNA^His(H)has no TΨC loop and tRNA^Cys(C)only has dihydorouridine arm and anticodon arm. The results of phylogenetic analysis based on the COX1 coding sequence showed that Z. chlorophthalmus had the closest relationship with Z. niveitarsis, which also belongs to the genus Zele. 【Conclusion】 We firstly sequenced and analyzed the complete mitochondrial genome of Z. chlorophthalmus. The results show that Z. chlorophthalmus belongs to Euphorinae and support the monophyly of Zele.

Contents of Vol. 63 Issue 8

2020, 63(8): 1039-1039.

Abstract ( 30 )

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