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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 April 2009, Volume 52 Issue 4
For Selected: View Abstracts Toggle Thumbnails
  • RESEARCH PAPERS
    Cloning, sequence analysis and expression of a matrix metalloproteinase gene(Bm-MMP)in the silkworm, Bombyx mori.
    2009, 52(4):  353-362. 
    Abstract ( 3007 )   PDF (2417KB) ( 974 )     
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    Matrix metalloproteinases (MMPs), a family of proteolytic enzymes, are involved in the degradation of extracellular matrix and/or basement membrane protein components. To study the essential function of MMPs in Bombyx mori, the full-length cDNA of Bm-MMP gene(Bm-MMP) was obtained with RACE and RT-PCR methods. Two alternative splice variants of Bm-MMP (Bm-MMP-V1 and Bm-MMP-V2) were obtained. The full-length cDNA of Bm-MMP-V1 is 2 257 bp, containing a 1 686 bp open reading frame, which encodes 561 amino acid residues, with calculated molecular mass of 62.3 kD. The full-length cDNA of Bm-MMP-V2 is 2 188 bp. The deduced amino acid sequences of Bm-MMP-V1 and Bm-MMP-V2 share the same high similarity (88.8%) with sequences of Gm1-MMP in Galleria mellonella, and their identities with Dm1-MMP in Drosophila melanogaster are 61.2% and 64.3%, respectively. The Bm-MMP-V1 was then constructed into vector pET28a(+) for prokaryotic expression. The results of SDS-PAGE and Western blot analysis indicated that a 62 kD protein with 6×His·tag was expressed in Escherichia coli BL21. The RT-PCR assay showed that the Bm-MMP was highly expressed in 4th-instar moulting larvae, mature larvae, 36 and 48 h of mounted silkworms, and prepupae. It is supposed that Bm-MMP is relative to the molting and metamorphosis. In addition, we found that LPS challenge induces a higher expression of Bm-MMP in hemocytes. The results suggest that Bm-MMP may be involved in the process of immunity. The successful cloning and expression of Bm-MMP provide a basis for the further study on its function.
    cDNA cloning and phylogenetic analysis of the heat shock protein 90 gene (hsp90) in two whiteflies, Bemisia tabaci (Gennadius) biotype B and Trialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae)
    2009, 52(4):  363-371. 
    Abstract ( 3518 )   PDF (2061KB) ( 864 )     
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    Bemisia tabaci (Gennadius) biotype B and Trialeurodes vaporariorum (Westwood) are worldwide pests. A pair of primers was designed based on the reported sequences of conservative regions of heat shock protein 90 gene (hsp90) family in other insects, and the fragments isolated from the two whitefly species were amplified by RT-PCR, and their full-length cDNA sequences were obtained by 3′ and 5′RACE. The full-length cDNA of hsp90 of two whitefly species contained 2 166 and 2 160 bp open reading frame (ORF) encoding 722 and 720 amino acids, respectively. The deduced amino acid sequence of hsp90 of T. vaporariorum was aligned with that of B. tabaci and both displayed a high degree of conservation (92.94%). The five highly conserved amino acid residues that characterize all the members of the HSP90 family and the C-terminal pentapeptide MEEVD were found in the two sequences. A phylogenetic tree was constructed based on all the complete amino acid sequences of HSP90 from Insecta by NJ method with genetic distance of Kimura 2-parameter model, which showed that the hsp90 presented good phylogenetic informativeness at both low and high taxonomic levels in Insecta. The results provide new insights into adaptation mechanisms of T. vaporariorum and B. tabaci to extreme environmental stress. Our data provide further support that the hsp90 sequences with ubiquity and high degree of conservation can provide a useful model for phylogenetic analysis.
    Seasonal changes in cold tolerance of desert beetle Anatolica polita borealis (Coleoptera: Tenebrionidae) and their physiological mechanisms
    2009, 52(4):  372-379. 
    Abstract ( 3230 )   PDF (1137KB) ( 1237 )     
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    Anatolica polita borealis lives in desert environment where the temperature difference varies greatly in the year around. In order to explore the cold tolerance of the beetle and its possible mechanisms, changes in the supercooling point (SCP), body water content, glycerol content, and thermal hysteresis activity (THA) of hemolymph of the adults from March to September were assayed, and the effect of 4℃ cold acclimation on its cold tolerance were also evaluated. The SCP of the larvae at different developmental stages were determined. The results showed that the SCP of adult A. polita borealis changed apparently over seasons, being -12.5℃ in March, -6℃ in July and -13.6℃ in September. Cold acclimation at 4℃ for 2 h or 24 h enhanced the cold resistance of the adult beetles at -10℃ for 40 min, and the survival rates were 70% and 90%, respectively, while it was 50% in the non-acclimated group. Body water content significantly decreased in summer compared to those in spring and autumn. The ratio of bound water to free water in March, July and September were 10.8∶1, 2.6∶1 and 5.4∶1, respectively. The regression equation of the glycerol content and the SCP of the adult was y=-0.6204x-5.681, R2=0.7714, and that of the hemolymph THA and the SCP was y=-5.26x-1.713, R2=0.9049, showing that the hemolymph THA had more effect on the decrease of the SCP of the adult than the glycerol content did. The SCP of the larvae decreased with the larval development. The results suggest that A. polita borealis obtains high cold tolerance by keeping low SCP via increasing the ratio of bound water to free water and the amount of antifreeze protein and glycerol.

    Isolation of dorsal unpaired median (DUM) neurons from the central nervous system of the cockroach Periplaneta americana and patch-clamp recording of their voltage-gated sodium current
    2009, 52(4):  380-385. 
    Abstract ( 3481 )   PDF (1436KB) ( 1143 )     
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    【Aim】 To grope for the method of isolation of dorsal unpaired median (DUM) neurons from the central nervous system of the cockroach Periplaneta americana and establish an electrophysiological model of DUM neurons. 【Methods】 The terminal abdominal ganglions of P. americana were dissected, DUM neuron cell bodies were obtained after enzymatic treatment with collagenase IA and mechanical dissociation of the median parts of the terminal abdominal ganglion, and the voltage-gated sodium current of DUM neuron cells was recorded by the patch-clamp technique in the whole-cell recording configuration. 【Results】 Isolated DUM neuron cells exhibited typical morphological characteristics of neuronal cells, which are nearly pyriform. Whole-cell sodium currents from DUM neuron cells showed the typical characteristics of sodium currents. 【Conclusion】 DUM neuron cells can be well obtained by enzymatic treatment, and sodium current can be studied by patch-clamp technique. The procedure described here provides a possible experimental model to study electrical mechanisms of insect nervous system.
    Biochemical mechanisms of beet armyworm (Spodoptera exigua) resistance to tebufenozide
    2009, 52(4):  386-394. 
    Abstract ( 3405 )   PDF (2076KB) ( 810 )     
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    In order to explore the biochemical mechanisms of the beet armyworm, Spodoptera exigua (Hübner), resistance to tebufenozide, activities of detoxifying enzymes including carboxylesterase (CarE) and glutathione-S-transferases (GSTs), protective enzymes including catalase (CAT), peroxidase (POD) and superoxide (SOD), and phenoloxidase (PO) and chitinase were tested in vivo in the susceptible population, selected population and natural population in Wuhan. The results showed that CarE activities of the selected population and natural population were 1.20- and 2.67-fold, and GSTs activities were 2.3- and 0.9-fold, respectively, compared with the susceptible population. There were significant differences in Km values of the CarE but no significant differences in Vmax values between the selected population and susceptible population. Compared with the selected population and susceptible population, the natural population had highly significant differences in Km and Vmax values of the CarE. PAGE results of the esterase isozymes also proved that the CarE activities and kinetic constants had changed dramatically. There were no significant differences in CAT and POD activities between the selected population and susceptible population, but SOD activity of the selected population increased obviously. Meanwhile the activities of the three enzymes in natural population also increased remarkably. The changes of SOD activities were more significant than those of CAT and POD activities. The PO and chitinase activities of the selected population increased 37.64% and 27.37%, respectively, and that of the natural population increased 59.63% and 60.29%, respectively, compared with the susceptible population. The kinetic constants of PO in the natural population and selected population had significant differences from those in the susceptible population. Refs. In Chinese
     
    Influence of temperature on functional response of Habrobracon hebetor (Say) (Hymenoptera: Braconidae) attacking larvae of Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)
    2009, 52(4):  395-400. 
    Abstract ( 3417 )   PDF (789KB) ( 1074 )     
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    In order to clarify the influence of temperature on the parasitism of Habrobracon hebetor (Say), the paralysis and the parasitism of the parasitoid H. hebetor as a biological control agent against Indian meal moth, Plodia interpunctella (Hübner), were determined at 17, 20, 23, 26, 29, 32 and 35℃ in the laboratory. The functional response of H. hebetor parasitizing P. interpunctella was examined at different host densities. A functional response equation was fitted to each temperature regime. The results indicated that within the temperature range of 17 to 29℃, the handling time was inversely proportional to temperature, ranged from 0.341 d at 17℃ to 0.068 d at 29℃. But over 29℃, the handling time was extended. The instantaneous search rate changed with temperature, being the lowest at 17℃ and highest at 29℃. But over 32℃, the instantaneous search rate decreased as the temperature increased. A temperature mediated functional response equation was fitted to the data, in which the handling time was a quadratic function of temperature. Accordingly, H. hebetor can parasitize more individuals of hosts within the temperature range of 26 to 29℃, which is favorable for its reproduction.
    Effect of temperature on post-diapause development in hibernating pupae of the cabbage butterfly, Pieris melete Ménétriés (Lepidoptera: Pieridae)
    2009, 52(4):  401-405. 
    Abstract ( 3529 )   PDF (855KB) ( 1015 )     
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    To understand the effect of temperature on post-diapause development of hibernating pupae of the cabbage butterfly, Pieris melete Ménétriés, the post-diapause development of hibernating pupae at different temperatures and the adult emergence under natural conditions were systematically investigated. The results showed that the threshold temperature and effective accumulated temperature for post-diapause development of over-wintering male and female were 7.1±1.5℃, 133.4±3.3 day-degrees and 7.4±0.4℃, 155.7±5.3 day-degrees, respectively. According to the observations of emergence of adults under natural conditions and the natural temperatures above development threshold for 7 successive years, the effective accumulated temperature for the emergence of 50% individuals was estimated as 142.2±12.2 and 149.2±13.8 day-degrees for the male and female, respectively, which were close to the theoretical value. The adult emergence date for 50% over-wintering individuals can be calculated by using the theoretical effective accumulative temperature according to natural temperatures between February and April based on the above data.
    Sequence variability of COI gene and genetic differentiation among the geographic populations of Caligula japonica (Lepidoptera: Saturniidae) in China
    2009, 52(4):  406-412. 
    Abstract ( 3689 )   PDF (1105KB) ( 1039 )     
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    Caligula japonica, an endemic species in eastern Asia, is not only an important forestry pest to be controlled, but also a precious wild silkmoth resource to be domesticated for silk production. In order to clarify the genetic relationship of the geographic populations of C. japonica, we determined the 574 bp segment of the mitochondrial cytochrome oxidase subunit I (COI) gene sequences from 12 geographic populations in China (GenBank accession no. FJ358506-FJ358517), and then analyzed the sequence variability of the COI gene and genetic differentiation among them. The identity of COI pairwise sequences was 99%-100% among the geographic populations of C. japonica, which indicated a low genetic diversity. In total, six haplotypes were identified within the sequences, with nine sites showing polymorphism and three haplotypes shared. Molecular phylogeny analysis showed that populations sampled were well divided into “Northern” and “Southern” groups. AMOVA analysis showed that there were apparent genetic differentiation between the “Northern” group and the “Southern” group (FST=0.478, P<0.001). It is inferred that the genetic differentiation between the “Northern” group and the “Southern” group should be related to ecology adaptation of C. japonica. The results of this study provide a basic molecular biology clue to the studies on population genetics and ecology of C. japonica.
    Genetic diversity and genetic differentiation of six geographic populations of Apis cerana cerana (Hymenoptera: Apidae) in East China
    2009, 52(4):  413-419. 
    Abstract ( 3396 )   PDF (899KB) ( 1235 )     
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    【Aims】 The genetic diversity and genetic differentiation of six populations of Apis cerana cerana distributed in different geographic areas in East China were surveyed using 23 microsatellite markers. 【Methods】 Using polymorphism information content (PIC), mean heterozygosity (H), number of effective alleles, genetic distances, gene flow (Nm) and F-statistics, we evaluated the genetic diversity and genetic differentiation. 【Results】 The number of alleles per locus ranged from 5(A014) to 30(AP043). All populations showed high-level heterozygosity, the lowest was Wuyishan population (0.4280) and the highest was Nanchang population (0.6329). Significant genetic differentiation was found among the six populations (P<0.01) and the average genetic differentiation coefficient of all the populations was 0.344. Neighbour-joining dendrogrm was constructed based on the Nei’s genetic distance, and three main clusters were found. 【Conclusions】 The genetic diversity and the genetic differentiation of the six populations of A. cerana cerana were significant. Through analyzing the correlation between genetic differentiation and geographical distance, we found that genetic differentiation among the six populations of A. cerana cerana was not be significantly related to geographical distance.
    A review of Chinese species of Leptomastidea Mercet (Hymenoptera: Encyrtidae)
    2009, 52(4):  420-423. 
    Abstract ( 3506 )   PDF (1999KB) ( 1065 )     
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    Six species of Leptomastidea are taxonomically studied from China. L. herbicola, L. rubra, L. shafeei are recorded from China for the first time. A key to Chinese species of Leptomastidea is given and photomicrographs are provided to illustrate morphological characters of the species. The specimens are deposited in the Institute of Zoology, Chinese Academy of Sciences, Beijing.
    Host-feeding behaviors of parasitoids on hosts and implications for biological control
    2009, 52(4):  424-433. 
    Abstract ( 4311 )   PDF (1454KB) ( 1301 )     
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    Many species of insect parasitoids not only parasitize hosts but can also feed and kill them. As for synovigenic parasitoid wasps, host-feeding behavior has been regarded as a common habit in them. In this article, host-feeding behaviors in hymenopteran parasitoids were summarized in the view of involved parasitoid species, foraging type, ecological significance, and impact factors over the past two decades. Parasitoid wasps kill significant numbers of hosts by feeding, as well as by parasitism, which plays important roles in reducing population size of insect pests. Meanwhile, host-feeding benefits the parasitoids by supplying nutrients needed for egg maturation and reproduction. Sometimes host-feeding also prolongs the longevity of parasitoids. Understanding the host-feeding strategies can provide important information for screening dominant insect parasitoids and evaluating their effectiveness in biological control on insect pests.
    Structures and functions of Drosophila melanogaster microRNAs and research strategies
    2009, 52(4):  434-444. 
    Abstract ( 4015 )   PDF (1700KB) ( 1827 )     
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    MicroRNAs (miRNAs) are small non-coding RNAs which are widespread in the genome of animals and plants. Recognized as key regulators of gene expression at the post-transcriptional level in eukaryotes, miRNAs inhibit the production of target proteins or induce degradation of mRNAs to control important physiological process by binding to specific region of target mRNAs via sequence complementarity. The identification of miRNAs in model insect Drosophila melanogaster was firstly summarized briefly in this article, and the research progress in structure, biosynthesis pathway and the mode of action were reviewed. miRNAs could regulate hundreds of target genes and their biological functions include the regulation of cell differentiation and apoptosis, organ and neural development, muscle differentiation, energy homeostasis and metamorphosis and/or the comprehensive regulation in D. melanogaster. miRNAs have the characteristics as “low abundance, short sequences and hard preconcentration”. The basic research strategies of obtaining miRNAs genes and identifying their functions include combining experimental biology with bioinformatics approaches. It is proposed that the identification of new miRNAs and their targets, and further study of their biological functions and genetic evolution may become important aspects in the research of insect miRNAs in the future.
    Triple infection of Wolbachia in Trichogramma ostriniae(Hymenoptera: Trichogrammatidae)
    2009, 52(4):  445-452. 
    Abstract ( 3424 )   PDF (977KB) ( 1283 )     
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    Wolbachia are common bacteria found in arthropods. Trichogramma ostriniae is the major Trichogramma species in maize fields in China and it has been reported that Trichogramma species harbored Wolbachia. In this study, the Wolbachia wsp and 16s rDNA gene sequences were used to detect the infection of Wolbachia in natural populations of T. ostriniae. The results indicated that T. ostriniae was triply infected with three strains of Wolbachia based on the wsp gene, i.e., wOstGDAa (GenBank accession no. EU157103), wOstGDAb (GenBank accession no. EU157104) and wOstGDB (GenBank accession no. EU157105). Phylogenetic analyses showed that wOstGDAa and wOstGDAb belong to supergroup A, while wOstGDB belongs to supergroup B. An extensive survey of Wolbachia infection in natural populations of T. ostriniae revealed that nearly all individuals tested were infected with wOstGDAa, wOstGDAb and wOstGDB. This is the first report that nearly 100% of the individuals in the population were triply infected with Wolbachia. According to our results, we suppose that Wolbachia may transfer among different Trichogramma species when they share a host egg.
    Fumigant toxicity of β-asarone extracted from Acorus calamus against four stored grain beetles
    2009, 52(4):  453-460. 
    Abstract ( 3855 )   PDF (1068KB) ( 1034 )     
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    Plant secondary metabolites play important roles in plant-insect relationships. Some plant-based extracts are insect repellents or have fumigant or contact toxicity. β-asarone is the main active ingredient of Acorus calamus L., a commonly used Chinese traditional medicinal herb. In this study, the knockdown and lethal impacts of β-asarone on four main stored-grain insects, Sitophilus zeamais, Rhyzopertha dominica, Tribolium castaneum and Callosobruchus maculatus were assayed in the laboratory. The study results showed that β-asarone extracted from A. calamus rhizome had significant knockdown and lethal impact on the pests. After the pests were treated with β-asarone for 120 h at the concentration of 50 μL/L, 100% of the C. maculatus, S. zeamais and R. dominica adults, and 50% of T. castaneum adults were knocked down; the mortality rates of T. castaneum, S. zeamais, R. dominica and C. maculatus adults were 8.89%, 81.23%, 97.78% and 100%, respectively. After 24 h exposure, the KC50 values for S. zeamais, R. dominica, T. castaneum and C. maculatus adults were 49.38, 102.96, 124.04 and 1.07 μL/L, respectively. After 120 h exposure, the LC50 values for S. zeamais, R. dominica, T. castaneum and C. maculatus adults were 17.82, 4.42, 116.48 and 0.73 μL/L, respectively. It is so concluded that the β-asarone extracted from A. calamus has distinct fumigant toxicity against all the four pests assayed, and thus can be exploited as a potential fumigant.
    Effect of light intensity on the photosensitivity and phototaxis behaviour of Chrysopa pallens Ramber (Neuroptera: Chrysopidae)
    2009, 52(4):  460-464. 
    Abstract ( 3630 )   PDF (544KB) ( 1221 )     
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    The responses of Chrysopa pallens Ramber to light stimuli with different intensities were investigated by means of electroretinogram (ERG) technique and behaviour measurement. The results were as follows: (1) The white light with given intensity (Log I=4.5~0.0) could evoke the ERG responses of the compound eyes of C. pallens after 2 h dark-adaption. A linear increase in ERG value occurred with the increase of the light intensity, and no plateau end was seen in the strongest intensity, which revealed that C. pallens owned almost the same photosensitivity within the test range of light intensity and was able to perceive stronger light. (2) Obvious phototactic responses in behavior upon given light stimuli that were stronger than Log I=4.0 were also observed, and the stronger the light intensity, the higher the percentage of behaviour response, especially in the range of stronger intensity (Log I=1.5~0.0). However, their photophobism was rather lower or irregular, with the maximum of 4.5%. It is so concluded that both the perception to light and subsequently phototaxis behavior of C. pallens depend on the light intensity obviously, there is no visible photophobism response in any case, and the response of primal receptor cell potential is accordant with the phototactic behavior in a certain range of light intensity, indicating that light intensity plays a subtle role during the light perception and succeeding phototaxis.
    Phylogenetic relationships among four Sarcoptes isolates from rabbits and swine in China based on the mitochondrial COI gene sequences
    2009, 52(4):  465-472. 
    Abstract ( 3438 )   PDF (1320KB) ( 897 )     
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    To clarify the taxonomic status of four Sarcoptes isolates from rabbits and swine in China, the cytochrome oxidase subunit I (COI) gene from these specimens was sequenced and compared with the homologous genes of other fourteen Sarcoptes isolates from other countries deposited in GenBank. The results of sequence analysis indicated that the lengths of COI genes in the four Sarcoptes isolates were all 1 427 bp. There was no insert or deletion. The base composition was obviously A+T biased, averaging 73%. Homology analysis indicated that the identity levels of nucleotide of COI genes among the four isolates from China ranged from 99.1% to 100.0%, while the homology of COI gene between the Sarcoptes isolated from China and the Sarcoptes isolates from human in Australia and those from other animals abroad ranged from 98.4% to 99.6%. The phylogenetic analysis showed that the relationships among Sarcoptes isolates from China and the Sarcoptes isolates from human in Australia and other animals abroad were close. Homology and phylogenetic analysis indicated that the Sarcoptes isolates from China and the Sarcoptes isolates from human in Australia and other animals abroad are conspecific.