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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 October 2010, Volume 53 Issue 10
For Selected: View Abstracts Toggle Thumbnails
  • RESEARCH PAPERS
    Molecular cloning, sequence analysis and tissue expression characterization of glutathione S-transferase gene BmGSTz1 in Bombyx mori
    YU Quan-you
    2010, 53(10):  1061-1068. 
    Abstract ( 3179 )   PDF (1537KB) ( 1130 )     
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    Glutathione S-transferases (GSTs) constitute a multifunctional superfamily in which Zeta class is widely distributed in animals, plants, and bacteria. In mammals, Zeta GSTs show maleylacetoacetate isomerase (MAAI) activity and participate in phenylalanine and tyrosine metabolism. In this study, expressed sequence tags (ESTs) were searched for the predicted GST gene from Bombyx mori, BmGSTz1. A contig containing 1 239 bp was assembled on the basis of ESTs of BmGSTz1, which extended into 3 and 5-UTR (untranslated region). The contig of BmGSTz1 perfectly matched to the corresponding region of the silkworm genome sequence and had a poly (A) signal in its 3-UTR. BmGSTz1 was composed of 4 introns and 5 exons, and the boundary between exon and intron conformed to the canonical GT-AG rule. TA cloning verified that the coding sequence (CDS) was 648 bp in length and encoded 215 amino acids. The putative molecular weight and isoelectric point of BmGSTz1 were 24.8 kD and 8.06, respectively. BmGSTz1 had relatively high similarities with GSTz1 from insects and mammalians. Phylogenetic analysis showed that BmGSTz1, DmGSTz1, AgGSTz1, ApGSTz1, and TcGSTz1 might be 11111 orthologues. The RT-PCR and microarray data indicated that BmGSTz1 was expressed in various tissues in Day-3 5th instar silkworm larvae. The results of sequence analysis and expression characterization suggest that BmGSTz1 might have the MAAI activity. The data presented in this study provide useful information for further studying the function of BmGSTz1.

    Mapping and expression analysis of GOBP/PBP subfamily gene cluster during pupal and adult stages of the silkworm, Bombyx mori
    ZHANG Sheng-xiang
    2010, 53(10):  1069-1076. 
    Abstract ( 6973 )   PDF (2043KB) ( 1268 )     
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    Odorant binding proteins (OBPs) in insects play a primordial role in foraging, courtshipping, multiplying, and chemical communication with the environments. General odorant binding protein/pheromone binding protein (GOBP/PBP) is an important monophyletic group of Lepidoptera OBP family. We analyzed the GOBP/PBP in the silkworm Bombyx mori, the model organism of Lepidoptera, using chromosome mapping and semi-quantitative RT-PCR for further understanding of the expression and function of GOBP/PBP. Chromosome mapping showed that these genes were organized in the nscaf3052 of chromosome 19 in the form of gene cluster, with similar gene structure and identical transcription direction, suggesting that they were originated from the duplication of homologous genes and probably possess functional similarity. Analysis of the expression profiles in different tissues of males and females during pupal and adult stages revealed that these genes possessed conspicuous temporal and spatial expression differences (P<0.05), the highest relative expression level occurred in the antenna, and lower relative expression levels in other most non-olfactory tissues without significant sex differences. The results suggest that these genes may have other functions undiscovered besides olfactory-related function.
    Molecular cloning, sequence analysis and developmental expression of the glycosyltransferase genes in the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)
    BAO Hong-wei
    2010, 53(10):  1077-1086. 
    Abstract ( 2790 )   PDF (1662KB) ( 958 )     
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    According to the homologous amino acid sequences in Caenorhabditis elegans and other insects, the full length cDNA sequences of 3 glycosyltransferase genes (named as Pxbre-3, Pxbre-4 and Pxbre-5) were cloned by RT-PCR and RACE-PCR from the midgut of 4th instar larvae of the diamondback moth, Plutella xylostella. The open reading frames of these genes were 1 383 bp, 1 230 bp and 1 041 bp, respectively. The deduced coding products had 460, 409 and 346 amino acids, respectively. These genes were homologous to the bre genes of Caenorhabditis elegans and had the predicted membrane-spanning regions and conserved motifs known to play key catalytic roles in glycosyltransferases. Thus, the three genes are inferred to code glycosyltransferases in P. xylostella. The mRNA expression of these three genes and Pxbre-2 was detected in different developmental stages (larva, pupa, and adult) of P. xylostella by real-time quantitative PCR, and the expression level was higher in pupa and adult. These results provide an important basis for investigating the possible involvement of glycosylphingolipid in resistance to Cry toxins in P. xylostella.

    Antennal ultrastructure and electroantennogram responses of Cyrtotrachelus buqueti Guerin-Meneville (Coleoptera: Curculionidae) to volatiles of bamboo shoot
    YANG Yao-jun
    2010, 53(10):  1087-1096. 
    Abstract ( 4010 )   PDF (3387KB) ( 1065 )     
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    Cyrtotrachelus buqueti Guerin-Meneville, a main bamboo pest, specializes in boring and damaging the top of tufting bamboo shoot. For analyzing the reason, the antennal ultrastructure of C. buqueti and the volatiles of different bamboo shoots and the antennal olfactory responses of female to the volatiles were studied with the scanning electron microscoopy and the gas chromatographic-mass spectrometry (GC-MS) and the electroantennogram (EAG), respectively. The results showed that the sensilla basiconica, with the ability of apperceiving the volatiles of bamboo shoot, was the most sensilla on the antenna of C. buqueti, and 28 bamboo shoot volatile compounds from bamboo shoot were discovered by GC-MS, in which the relative content of aldehydes was the highest, and those of alcohols and acids come second. The EAG analysis deduced that the relative EAG values of benzaldehyde with the highest relative EAG values and other 12 volatiles were significantly higher than the control. These results suggest that the high content or the special volatiles of the top of tufting bamboo shoot might be the important odor signals which allure C. buqueti to tend towards the top of bamboo shoot, and that C. buqueti might identify the bamboo shoot by the chemistry finger map with primary benzaldehyde and special proportion of components. This study provides a theoretical basis for developing attractant of C. buqueti.

    Effects of RNAi-mediated silencing of an aminopeptidase N gene Haapn1 and a cadherin gene Ha_BtR on Cry1Ac toxicity against Helicoverpa armigera (Lepidoptera: Noctuidae)
    ZHOU Hui-dan
    2010, 53(10):  1097-1103. 
    Abstract ( 3727 )   PDF (1176KB) ( 1252 )     
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    Aminopeptidase N (APN) and cadherin are key receptors of Bacillus thuringiensis Cry1A toxins in brush border membrane vesicles (BBMVs) of lepidopteran insects. Effects of RNAi-mediated silencing of an APN gene Haapn1 and a cadherin gene Ha_BtR on Cry1Ac toxicity were investigated by injecting dsRNAs of these two genes into the 4th instar larvae of Helicoverpa armigera in this experiment. Reduction of mRNA expression of Haapn1 (30%-49%) and Ha_BtR (30%-37%) was observed in the larvae injected respectively with Haapn1 dsRNA and Ha_BtR dsRNA (1 μg/larva) compared with the control larvae injected with elution solution (ES) only. Mortality of larvae injected with Haapn1 dsRNA was significantly lower than that of the control larvae injected with ES in treatments of 40 and 70 μg/cm2 of activated Cry1Ac, but there was no difference in mortality of larvae injected with either Haapn1 dsRNA or ES in treatments of 100 and 170 μg/cm2 of Cry1Ac protoxin. RNAi-mediated gene silencing by injecting Ha_BtR dsRNA had no effect on toxicity of both activated Cry1Ac and Cry1Ac protoxin. However, toxicity of both activated Cry1Ac and Cry1Ac protoxin against the 4th instar larvae injected with a mixture of Haapn1 dsRNA and Ha_BtR dsRNA was significantly reduced. These results further confirm that both Haapn1 and Ha_BtR are functional receptors of Cry1Ac in H. armigera, and both of them are involved in intoxication of Cry1Ac. Our results also suggest that mutations occurring in either Haapn1 or Ha_BtR may result in resistance to Cry1Ac in H. armigera.

    Antifeedant activity of Interruptin B against Plutella xylostella and Ostrinia furnacalis and cytotoxicity against Spodoptera litura ovary cells
    HUANG Su-qing
    2010, 53(10):  1104-1110. 
    Abstract ( 3573 )   PDF (1056KB) ( 1090 )     
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    In order to ascertain the insecticidal activity and probe into the insecticidal mechanism of Interruptin B, we studied its biological activity against the 3rd larvae of Plutella xylostella and Ostrinia furnacalis with leaf dipping method and the effect on the number of blood corpuscles in Spodoptera litura larvae by injection and blood cell count, and observed the cell proliferation inhibition of S. litura ovary cells (SL cells) using MTT method. Meanwhile, we observed its effect on the shape, density and the adherence rate of cells by inverted microscope. The results indicated that Interruptin B had the antifeedant and insecticidal activity against the 3rd instar larvae of P. xylostella and O. furnacalis. At 48 h post treatment, the AFC50 values of Interruptin B against the 3rd instar larvae of O. furnacalis and P. xylostella were 108.56 g/mL and 143.88 μg/mL, respectively, while the LC50 values were 346.23 μg/mL and 194.32 μg/mL, respectively. This compound also had strong inhibitive activity on the growth of S. litura larvae, its IC50 values on SL cells at 24 and 48 h post treatment were 13.51 μg/mL and 4.11 μg/mL, respectively. Significant decrease of cell density were observed by microscope in the Interruptin B treated SL cells (P<0.05). The deformation rates of SL cells were 28.18%, 83.90%, 85.18%, 93.93% and 100%, and the adherence rates were 96.59%, 89.90%, 83.18%, 5.06 % and 1.09% at 3, 6, 12, 24 and 48 h post treatment, respectively. The deformation rate and adherence rate of SL cells treated with Interruptin B were significantly different from those in the control at 6-48 h post treatment (P<0.05. The results show that Interruptin B possesses the antifeedant and insecticidal activity against P. xylostella and O. furnacalis, and can decrease the blood cells of the larvae of S. litura and the density of SL cells, and has strong inhibitive activity on the growth of S. litura larvae. In addition, it can inhibit cell proliferation, change the cell shape, and decrease the adherence rate of SL cells. These suggest that the insecticidal activity of Interruptin B is realized by affecting the cell activity of insects.

    Reproductive disadvantage in an Indian strain of malarial vector Anopheles stephensi Liston (Diptera: Culicidae) on selections with deltamethrin/synergized deltamethrin
    Sarita KUMAR
    2010, 53(10):  1111-1118. 
    Abstract ( 3005 )   PDF (1272KB) ( 1035 )     
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    The knowledge of reproductive fitness in susceptible and resistant mosquitoes could be important in planning and implementing mosquito control programs. The laboratory studies were carried out to reveal the variations in the reproductive fitness of parent (AnS) and resistant (AnR) strains of malarial vector Anopheles stephensi originating from Delhi, India on selections with deltamethrin (AnDL) or the combination of deltamethrin and PBO (15) (AnDP) at the larval stage and selections with deltamethrin at the adult stage (AnDA). The reproductive fitness was evaluated in terms of the fecundity, fertility, egg hatchability and the length of gonotrophic cycles. The AnR strains exhibited 60%-73% reduced duration of the gonotrophic cycles when compared with AnS strain. There was a considerable decrease in the egg production, ranging from 14.5% to 37.9% in AnR strains as compared to the AnS strain. The maximum reduction was observed in AnDL40 strain with the highest levels of deltamethrin resistance. The results indicate the possible positive correlation between the levels of deltamethrin resistance and the reproduction disadvantage. This correlation was further confirmed by 19.4% to 30.9% decrease in the hatchability of eggs of the AnDL40 strain with respect to that of the parent strain. A worth mentioning observation of the reduced reproductive fitness in RDp strains suggests the efficacy of synergized deltamethrin selections in not only decreasing the deltamethrin resistance levels but also reducing the frequency of resistant individuals. The diminished reproductive fitness in adult-selected strains possessing negligible resistance to deltamethrin implicates the higher usefulness of deltamethrin as an adulticide in comparison to as a larvicide against An. stephensi. The results suggest that the reduced reproductive fitness of resistant genotypes in the population can eliminate heterozygotes and resistant homozygotes by implementing different resistancemanagement strategies against An. stephensi.

    Influences of feeding artificial diet containing different concentrations of Cry1Ac toxin by early-instar larvae of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) on its larval development and adult reproduction
    CHEN Jian
    2010, 53(10):  1119-1126. 
    Abstract ( 3450 )   PDF (1292KB) ( 1062 )     
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    To obtain a full-scale assessment of the influences of transgenic Bt crops on the beet armyworm, Spodoptera exigua (Hübner), larval development and adult reproduction of the S. exigua were examined when early-instar larvae fed on artificial diet containing different concentrations of Cry1Ac toxin for six days and then transferred to non-Cry1Ac toxic diet. The results showed that the corrected mortality of S. exigua significantly increased with increasing of concentration of Cry1Ac toxin and prolonging of feeding time when early-instar larvae fed on artificial diet containing Cry1Ac toxin for six days. As compared to the control fed on nonCry1Ac toxic diet, larval body weight was significantly decreased when early-instar larvae fed on the artificial diet containing Cry1Ac toxin. Larval duration, pre-pupal duration, male and female pupal duration were all significantly delayed, but male and female pupal body weight were not significantly different from those of control. Percentage of pupation was significantly declined, but the emergence rates were not significantly different from those of control. Pre-oviposition period of adult was significantly delayed, but oviposition period was not significantly different from that of control except that adults with early-instar larvae fed on the 5 μg/g Cry1Ac toxin diet had a significantly longer oviposition period (1.3 d longer). The highest number of eggs laid per female was observed when the early-instar larvae fed on the artificial diet containing 10 μg/g Cry1Ac toxin, but all the Cry1Ac toxin diet treatments had no significant difference compared with the control. Female longevity was all significantly prolonged, but not male except the treatment of the highest concentration (80 μg/g) of Cry1Ac toxin diet which resulted in a significantly longer longevity (2.4 d longer). These results indicated that the artificial diet containing different concentrations of Cry1Ac toxin have significant inhibition on the growth and development of S. exigua or directly resulted in death in larval stage, but when larvae were transferred to non-Cry1Ac toxic diet, they could recover fast, pupate, emerge and oviposit successfully. Therefore, once the early-instar larvae could survive and complete a generation after eating the plant tissue expressing Cry1Ac protein in the late development of the transgenic Bt crops, this will bring more risk of S. exigua on resistance to Bt crops, so it needs to develop an appropriate management strategy for this pest in agricultural Bt crops ecosystem.

    Influence of land uses on species diversity of carabid beetles (Coleopeta, Carabidae) in Bashang region, Hebei, Northern China
    WANG Jian-fang
    2010, 53(10):  1127-1134. 
    Abstract ( 3424 )   PDF (6971KB) ( 1314 )     
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    To study the species diversity pattern of carabids and its relation with environment factors in different ways of land use, systematic investigation of carabid beetles were conducted from May to October in 2009 by pitfall traps in Saibei Administrative Region, Hebei Province, Northern China. Carabid beetles caught from six habitats of different land uses, i.e., shrubmeadow, potato land, clover field, enclosed meadow, moderately grazed meadow and heavily grazed meadow, were identified and analyzed. The results showed that a total of 10 804 carabid beetles were collected, belonging to 10 genera and 18 species. Among all collected specimens, Pterostichus fortipes, Cymindis binotata and Carabus latreillei accounted for 67.5%, 7.53% and 7.06% of total specimens, respectively. The highest density of carabids was found in clover field, followed by potato field, and the lowest density in heavily grazed meadow. As to clover field, there was almost no disturbance, and the species richness, Margalef richness index, Shannon-Wiener diversity index and the evenness index of carabids were higher in clover field than other ones. The result of clustering analysis showed that the similarity of beetle community in different habitats accords with interference strength and land use patterns. Beetles seasonal activities were mainly from June to September, and peaked in July and August. Various species in different land use patterns have different seasonal trends. The number of carabid individuals increased with the plant biomass. Pterostichus fortipes mostly reached a peak in July when plants grow in luxuriance, except that the peak within the enclosed meadow appeared in August; Cymindis binotata peaked in 8-9 months. Canonical corresponding analysis indicated that the soil moisture, soil temperature, plant cover, plant biomass and plant height were important environmental factors in carabid community composed. The results suggest that the disturbance of different land uses influenced the environments where carabid beetles survived, and then influenced the species composition and quantity distribution pattern.

    Genetic differentiation and gene flow among different geographical populations of the Asian corn borer, Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae) in China estimated by mitochondrial COⅡ gene sequences
    LI Jing
    2010, 53(10):  1135-1143. 
    Abstract ( 3667 )   PDF (1249KB) ( 1295 )     
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    To investigate the genetic differentiation and gene flow among different populations of the Asian corn borer, Ostrinia furnacalis (Guenée), in China, we analyzed CO sequences of mitochondrial DNA in 17 geographical populations. In the total 413 CO gene sequences obtained, 34 variable sites and 35 haplotypes were observed. The mean haplotype diversity of all populations was 0.811, whereas it varied from 0.424 to 0.862 within population. The average gene flow (Nm) among the 17 populations was 2.02. The overall Fst value was 0.234. Molecular variance (AMOVA) analysis indicated that a high proportion of the total genetic variance was attributable to variations within populations (76.45%). The Tajima’s D value neutrality test results suggest that for the Asian corn borer, there might be no population expansion, so their population sizes were steady. The genetic distance was not significantly correlated with the geographical distance between populations. The phylogenetic tree revealed no obvious geographical pattern for the prevalence and distribution of the haplotypes.

     

    Analysis of genetic variation in different geographical populations of Pieris rapae Linnaeus (Lepidoptera: Pieridae) based on rDNA ITS-1 sequence evidence
    MAO ZengHui
    2010, 53(10):  1144-1152. 
    Abstract ( 3897 )   PDF (1174KB) ( 1175 )     
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    In order to investigate the genetic variations of different geographical populations of Pieris rapae Linnaeus in China, the ribosomal DNA gene interval transcribed spacer 1 (ITS-1) sequences of 79 indididuals from 16 areas were determined and analyzed. Upon these gene sequence data and using Pieris canidia as the outgroup, we reconstructed phylogenetic trees by means of neighbor-joining and minimum evolution analyses, aiming to clarify their biogeographical divergence pattern. The results of the sequence variation analyses showed that the sizes of the ITS-1 of Pieris rapae range from 337 to 458 nucleotides in length. Aligned with the ClustalW software, the total 347 sites, which contain 281 conserved, 63 variable and 16 parsimonious informative, were obtained. Meanwhile, for the whole population of this study, the nucleotide diversity Pi and the Theta (per site) Eta were calculated to be 0. 014 and 0.041, respectively. Moreover, total 48 haplotypes were identified and the haplotype diversity 0.989 was obtained by the software DnaSP. Additionally, the fixation index (FST) 0.351 (P<0.05) was calculated by the analysis of molecular variance (AMOVA) software. The result of phylogenetic analysis indicated no pronounced correlation between their haplotypes and the geographical regions. Based on the phylogenetic trees, it is inferred that the Pieris rapae in China probably colonized first in the Liaoning, Inner Mongolia and Beijing, and then spread to other areas by transportation of their host plants and migration of their adults.

    A review of the genus Zhengitettix Liang (Orthoptera:Tetrigoidea) with description of one new species
    ZHENG Zhe-min
    2010, 53(10):  1153-1156. 
    Abstract ( 2882 )   PDF (568KB) ( 1120 )     
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    The genus Zhengitettix from China was reviewed, with six species recorded, including one new species, Zhengitettix triangularis sp. nov., which was collected from Yunnan, S.W. China. The new species is allied to Z. hainanensis Liang, 1994, but differs in: width of frontal ridge sulcus as wide as the width of basal segment of antenna; antennae inserted between the lower margin of eyes; hind process reaching one third of top part of hind tibia; hind wing reaching extending over the top of hind process; hind tibia black. A key to species of the genus is given.

    Advances in insect octopamine and tyramine
    WU Shun-fan
    2010, 53(10):  1157-1166. 
    Abstract ( 4718 )   PDF (3977KB) ( 1648 )     
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    Octopamine (OA) and tyramine (TA) play various important physiological roles in insects. They modulate various organs and behaviors in a coordinated way, such as peripheral organs, learning and memory, circadian rhythm, etc. OA and TA are considered to be the invertebrate counterparts of adrenaline and noradrenaline in vertebrates. They are decarboxylation products of the amino acid tyrosine. Although tyramine is the biological precursor of octopamine, both compounds are independent neurotransmitters, acting through distinct G protein-coupled receptors. In recent years, OA and TA in insects, especially their receptors, have attracted more studying. In this review, we summarized the current knowledge on the biosynthesises of OA and TA, distributions in nervous and nonnervous tissues, presynaptic reuptakes and various physiological functions in insects. Especially, the recent progress about gene cloning, signal transduction and pharmacological characterization of insect octopamine and tyramine receptors was reviewed in detail.
    Research advances in diapause in braconids
    LI Yu-yan
    2010, 53(10):  1167-1178. 
    Abstract ( 2805 )   PDF (2010KB) ( 1147 )     
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    Diapause is widespread in a variety of braconids, which are natural enemies for many pest insects. By regulating diapause of braconids, the following objectives can be achieved: increasing the shelf-life of braconid wasps, prolonging the time of prevention and control, and improving the braconids’ resistance ability and fecundity. These are important for production and application of braconids. This review summarized 2 545 literatures of diapause in the world since 1910. In total 37 species in Braconidae, belonging to 16 genera and 7 subfamilies, were reported for their clear diapause induction or diapause termination. Among them, the diapause characteristics of 23 species were described in detail. Majority of braconids diapaused in prepupae, followed by larval diapause, a small number of the braconids diapaused in adult. The diapause sensitive period varies in different species. Braconids have relatively long diapause duration, because most of them can be maintained for several months, and the longest one is up to 14 months. Photoperiod, temperature and host are major factors affecting the diapause of braconids. To some extent, humidity, parents and host plants can also affect the diapause process of braconids. Currently, the research of diapause in braconids is limited to biological observation, the physiological characteristics, hormone regulation, molecular regulation, etc. have not yet been studied, so there are many issues to be further explored.

    Cellulase activity and its relationship with host selection in the Asian longhorned beetle, Anoplophora glabripennis (Coleoptera: Cerambycidae)
    LI Xiao-juan
    2010, 53(10):  1179-1183. 
    Abstract ( 3028 )   PDF (1122KB) ( 1334 )     
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    To investigate the relationship between cellulase activity and host selection, Anoplophora glabripennis (Motsch.) larvae from four different host trees (Populus alba var. pyramidalis Bunge, Populus nigra var. thevestina (Dode) Bean, Populus simonii × Populus pyramidalis cv. opera Hsu and Salix matsudana f. lobato-glandulosa Fang et Liu) and adults fed on five different tree species were selected. The enzyme activities of endoglucanase andβ-glucosidase in the intestines of the insects were measured. The results showed that in the larvae, the activity of endoglucanase ranged from 1.36 to 2.71 μmol glucose/(g FW·h), and the activity of β-glucosidase ranged from 2.57 to 4.86 μmol glucose/(g FW·h). In the adults fed on different tree species, the activity of endoglucanase ranged from 4.08 to 9.27 μmol glucose/(g FW·h), and the activity of β-glucosidase ranged from 2.87 to 6.08 μmol glucose/(g FW·h). There are no significant differences in cellulase activities among the larvae from different host trees. However, the tree species which the adults fed upon has great effect on the activity of cellulase in the adults.

    Olfactory response of Trichogrammatoidea bactrae and Trichogramma confusum (Hymenoptera: Trichogrammatidae) to different components of kairomones of the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)
    LU Yan-qing
    2010, 53(10):  1184-1189. 
    Abstract ( 3533 )   PDF (938KB) ( 1188 )     
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    The egg parasitoids Trichogrammatoidea bactrae Nagaraja and Trichogramma confusum Viggiani are potential biological control agents for the diamondback moth (DBM), Plutella xylostella (L.). In this study, the olfactory response of two parasitoids to saturated hydrocarbons from host egg shells and adult scales of P. xylostella were measured using a Y-tube olfactometer. The results indicated that the percentages of mated females of T. bactrae entering the treatment arms of 2,6,10,14-tetramethyl-pentadecane, pentadecane and heptadecane were 80.65%, 68.75% and 66.67%, respectively, significantly higher than those entering the control arms, suggesting that these three compounds could stimulate an intensive search behavior by T. bactrae. However, the parasitoid did not respond to other 10 hydrocarbons. The percentages of mated females of T. confusum entering the treatment arms of 2,6,10,14-tetramethyl-pentadecane, pentatriacontane and pentadecane were 84.38%, 70% and 62.16%, respectively, significantly higher than those entering the control arms, revealing that T. confusum were significantly attracted by those three compounds. While the numbers of T. confusum entering the treatment and control areas had no differences in the tests with other 10 hydrocarbons. In the case of unmated males of T. bactrae and T. confusum, there was no significant difference in entering numbers of wasps between the treatment and control arms for all 13 saturated hydrocarbons.

    Overwintering stage and habitat of the natural populations of the alligatorweed flea beetle, Agasicles hygrophila (Coleoptera: Chrysomelidae) in Xiangtan, Hunan, Southern China
    LIU Yu-fang
    2010, 53(10):  1190-1194. 
    Abstract ( 3169 )   PDF (995KB) ( 1033 )     
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    The egg parasitoids Trichogrammatoidea bactrae Nagaraja and Trichogramma confusum Viggiani are potential biological control agents for the diamondback moth (DBM), Plutella xylostella (L.). In this study, the olfactory response of two parasitoids to saturated hydrocarbons from host egg shells and adult scales of P. xylostella were measured using a Y-tube olfactometer. The results indicated that the percentages of mated females of T. bactrae entering the treatment arms of 2,6,10,14-tetramethyl-pentadecane, pentadecane and heptadecane were 80.65%, 68.75% and 66.67%, respectively, significantly higher than those entering the control arms, suggesting that these three compounds could stimulate an intensive search behavior by T. bactrae. However, the parasitoid did not respond to other 10 hydrocarbons. The percentages of mated females of T. confusum entering the treatment arms of 2,6,10,14-tetramethyl-pentadecane, pentatriacontane and pentadecane were 84.38%, 70% and 62.16%, respectively, significantly higher than those entering the control arms, revealing that T. confusum were significantly attracted by those three compounds. While the numbers of T. confusum entering the treatment and control areas had no differences in the tests with other 10 hydrocarbons. In the case of unmated males of T. bactrae and T. confusum, there was no significant difference in entering numbers of wasps between the treatment and control arms for all 13 saturated hydrocarbons.