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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 2012, Volume 55 Issue 4
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    Deletion of gene fragment Df(3R)Espl3/TM6C affects sleep duration in Drosophila melanogaster
    ZHANG Ke-Xing, LI Ting-Li
    2012, 55(4):  371-375. 
    Abstract ( 3251 )   PDF (808KB) ( 1322 )     
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    【Aim】 Sleep in Drosophila melanogaster shows biological rhythm, and it can be controlled by different genes. In order to find the proper gene that affects sleep duration, we screened the genotypes of D. melanogaster associated with sleep duration. 【Methods】 The 7-day-old adults of the wild CS strain and the strains with gene deletion including 5601, 8904, 7061, 7146, 27327, 669, 8103, 691, 9697, 24416, 26525, 5411, 3096, 5877 and 7682 of D. melanogaster were used for screening. Drosophila Activity Monitoring System (DAMS) was used to record the total sleep duration within 24 h. The data obtained were compared among different strains. 【Results】 Compared with the wild CS strain, strain 5601 with deletion of gene fragment Df(3R)Espl3/TM6C had significantly shorter total sleep duration (P<0.001). 【Conclusion】 The gene fragment Df(3R)Espl3/TM6C is related to the sleep duration in D. melanogaster. This research provides data support for revealing the genes which are related to sleep in D. melanogaster and more clues to studying human sleep.
    Isolation and identification of the aggregation pheromone released by male adults of Frankliniella intonsa (Thysanoptera: Thripidae)
    ZHU Xiao-Yun, ZHANG Peng-Jun, Lu Yao-Bin
    2012, 55(4):  376-385. 
    Abstract ( 4203 )   PDF (1337KB) ( 2019 )     
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    Identification of aggregation pheromone released by Frankliniella intonsa males play a key role in bio-control of this pest. Except for the western flower thrips Frankliniella occidentalis, little is understood on aggregation pheromones in other thrips species. In the laboratory we tested the behavioral responses of adult F. intonsa and F. occidentalis to odor sources emitted from their corresponding adult males with Y-tube olfactometer. Head-space volatiles released by adult males of F. intonsa were collected using solid-phase microextraction (SPME) and identified by gas chromatography-mass spectrometry (GC-MS) with different GC columns (BGB-176 SE and CP-chirasil-Dex CB). Behavioral results showed that both male and female F. intonsa were attracted to the odors released by conspecific males. GC-MS analysis showed that two major components in head-space volatiles were released by F. intonsa, i.e., (R)-lavandulyl acetate and neryl (S)-2-methylbutanoate, which are the same compounds that are reported in volatiles from F. occidentalis males. However, quantitative analysis showed that the ratios of (R)-lavandulyl acetate to neryl(S)-2-methylbutanoate released by F. intonsa and F. occidentalis adults differed. Behavioral experiments further showed that the difference in the ratio of the two components plays an important role in interspecies identification between F. intonsa and F. occidentalis. The results suggest that different species of thrips of the same genus Frankliniella may share the same aggregation pheromones.
    Changes in external morphology and integument ultrastructure of the 5th instar larvae of Lymantria dispar (Lepidoptera: Lymantridae) treated by 20hydroxyecdysone
    YU Jie, CHI De-Fu, LI Xiao-Can, YU Jia
    2012, 55(4):  386-394. 
    Abstract ( 3699 )   PDF (14893KB) ( 1728 )     
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    To ascertain the definite influence process of 20-hydroxyecdysone (20E) on cuticle, epidermic cells and cell organelle of integument in the molting process, transmission electron microscope was used to determine the influence of 20E on the integument ultrastructure of newly moulted 5th instar larvae of Lymantria dispar (Linnaeus). The results showed that larvae fed with white birch leaves soaked in high concentration of 20E ingested about 400 μg 20E when they stopped feeding within 6 h after treatment. At around 12 h post treatment, the microvilli on apical plasma membrane of epidermal cells reduced, and the ecdysial space started to form between the old cuticle and epidermal cells. The old head capsule started to break away from the larval head. At 24 h post treatment, the ecdysial space increased continually. The old cuticle separated further with epidermal cells and new cuticulin layer began to form. At around 36 h after treatment, short microvilli were formed at the apical plasma membrane, and a lot of electron lucent vesicles appeared at the cytoplasmic region. Epicuticle, exocuticle and about 8 layers of endocuticular lamellae were synthesized in the new cuticle. At 48 h after treatment, the bounds between apical plasma membrane and epidermal cells became obscure. Endocuticular lamellae were continuously synthesized to 16 layers. At 72 h post treatment, a large number of electron lucent vesicles appeared in the epidermal cells, and endocuticular lamellae were synthesized to about 20 layers. At 96 h after treatment, there were fewer organelles in epidermal cells of the treatment groups than in the control group. A small percentage of blank space occurred around nucleolus, and the contents in cytoplasm were reduced. The bodies of treated insects became nigrescence and shrinking, and they were close to death. The number of endocuticular lamellae maintained to be about 20 layers.In the control groups, however, at 6-96 h after treatment the larvae were active and fed normally, and no molting phenomenon was observed by external observation and transmission electron microscope experiments in these larvae. The cuticle of the larvae was composed of epicuticle, exocuticles and normal layers of endocuticular lamellae. The microvilli density was high. Those organelles were typical and active. The cell boundaries were visible in the cytoplasm area, where the inclusions are rich. The secretion activity of epidermal cell was vigorous, and the endocuticular lamellae increased continuously to 50 layers with increase of the treatment time. It is so inferred that 20E could lead to lethal moulting of 5th instar larvae of L. dispar.
    Dynamics of F-actin during spermiogenesis in Gampsocleis gratiosa (Orthoptera: Tettigoniidae)
    ZHOU Na, CHANG Yan-Lin, WANG Li
    2012, 55(4):  395-402. 
    Abstract ( 3026 )   PDF (18125KB) ( 1441 )     
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    In order to understand the dynamics of F-actin during spermiogenesis in Gampsocleis gratiosa Brunner von Wattenwyl, we demonstrated the cellular localization of F-actin during spermiogenesis using differential interference contrast microscopy and immunofluorescence microscopy, and observed the ultrastructure of the acrosomal complex using transmission electron microscopy. The results show that F-actin is detected in the subacrosomal space at the early spermatid stage, with shape from globular to rod-cone-like. At the middle spermatid stage, F-actin is detected in the subacrosomal space and two sides of the nuclear forepart, and looks like an inverted Y. At the late spermatid stage, F-actin looks like an arrow only in the extension wings of the acrosomal complex. F-actin was depolymerized and disappeared, only being located at subacrosomal region at the middle spermatid stage. The results suggest that the dynamics of F-actin is associated with the shape of spermatid nucleus and sperm head, and the acrosomal architecture and nuclear morphogenesis are supported by a dynamic F-actin skeleton during spermiogenesis. In addition, we discovered some cytoplasm droplets in the tail of immature sperm. Immunocytochemical and ultrastructural analysis indicated that these cytoplasm droplets contain abundant F-actin. The F-actin of cytoplasm droplets can be involved in expelling redundant cytoplasm and organelles during spermiogenesis. This study on the dynamics of F-actin provides the foundation to clarify the function and mechanism of cytoskeletal proteins during insect spermiogenesis.
    Molecular cloning and cellular localization of Opdi108 from Ophiusa disjungens nucleopolyhedrovirus
    CHANG Run-Lei, LIU Li, WEI Chun-Mei, LANG Guo-Jun, XU Wen, MAO Shan-Shan, LIN Tong
    2012, 55(4):  403-411. 
    Abstract ( 3437 )   PDF (14958KB) ( 1237 )     
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    Abstract: 【Aim】 Ophiusa disjungens (Lepidoptera, Noctuidae) is one of the main insect pests that attack eucalyptus. A new nucleopolyhedrovirus (NPV) called Ophiusa disjungens NPV (OpdiNPV) was recently isolated from diseased larvae. The objective of this research was to understand OpdiNPV at the molecular level. 【Methods】 A PstⅠ genomic fragment of OpdiNPV was cloned, sequenced and analyzed. 【Results】 A homologue of Ac108 gene, assigned as Opdi108 (GenBank accession number EU 732666), was found in this fragment. The open reading frame (ORF) of Opdi108 is 225 bp in length and its encoded protein has 16%-37% amino acid identities with other known baculovirus homologous proteins. Upstream of the start codon ATG of Opdi108, contains a late promoter motif TAAG. The ORF of Opdi108 with His-tag at C-terminus was expressed as a protein in Escherichia coli with a molecular mass of 28.7 kDa. EGFP-Opdi108 fusion protein was expressed in Trichoplusia ni (Tn) cells using Bac-to-Bac system, suggesting that Opdi108 was located mainly in the cytoplasm of infected cells at 24 h post-infection (p.i.) and 72 h p.i. 【Conclusion】 This study provides a genetic basis for the development of the virus OpdiNPV as a biopesticide or an engineered pesticide to control O. disjungens and other lepidopteran insects.
    Effects of periplocosides P and E from Periploca sepium on the proteinase activities in the midgut of larvae of Mythimna separata and Agrotis ypsilon (Lepidoptera: Noctuidae)
    CHEN Cui-Cui, GAO Lu-Tong, SHI Bao-Jun, WEN Wan-Dong, HU Zhao-Nong, WU Wen-Jun
    2012, 55(4):  412-419. 
    Abstract ( 3482 )   PDF (1046KB) ( 1169 )     
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    Periplocoside P, which was isolated from the root bark of the insecticidal plant Periploca sepium Bunge, has strong insecticidal activity. To explore the insecticidal mechanism of periplocoside P, the classical determination methods for insect protease activity were used to compare the different effects on the activities of trypsin-like protease and chymotrypsin-like protease in the midgut of the 6th instar larvae of Mythimna separata and Agrotis ypsilon beween periplocoside P and periplocoside E which has no insecticidal activity. The results showed that periplocoside P displayed strong activation effect on the weakly alkaline trypsin-like protease activity in the midgut of M. separata larvae, which was 3.43 times as high as the control, and the activation time last up to 8 h; while periplocoside E did not show any activation effect. Significant differences at the 0.01 level between the effects of periplocosides P and E on the weakly alkaline trypsin-like protease activity of M. separata larvae were observed. At 2 h, 4 h and 8 h after treatment, the weakly alkaline trypsin-like protease activity in the midgut of M. separata larvae treated by periplocoside P were 15.4, 106.8 and 242.7 times as high as that in the midgut of M.separata larvae treated by periplocoside E. The results of protease activity determination also showed that the trypsin-like protease activity in the midgut of A. ypsilon larvae was relatively low, and the activation effect of periplocoside P on trypsin-like protease was also weak, compared to that on M. separata, which may be one of the factors that periplocoside P had insecticidal activity against M. separata, while A. ypsilon was insensitive to it. In addition, periplocosides P and E showed no obvious effect on chymotrypsin-like protease activity in the midgut of the tested insects. It is so inferred that the activation of the weakly alkaline trypsinlike protease in the midgut of M. separata may be one of the factors that periplocoside P causes toxicity to insects.
    Effect of temperature on toxicities of scopoletin and bisdemethoxycurcumin against Tetranychus cinnabarinus (Acari: Tetranychidae)
    YANG Zhen-Guo, ZHANG Yong-Qiang, DING Wei, LUO Jin-Xiang, QIN Pei-Yuan
    2012, 55(4):  420-425. 
    Abstract ( 3212 )   PDF (4364KB) ( 1154 )     
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    The toxicities of botanical acaricides scopoletin and bisdemethoxycurcumin (BDMC) were investigated for their acaricidal activity against female adults of the carmine spider mite, Tetranychus cinnabarinus, by slidedip bioassay at different temperatures in order to ascertain the temperature effect of scopoletin and BDMC. Both scopoletin and BDMC displayed a positive temperature coefficient at temperatures from 8 to 26℃ and a negative temperature coefficient at temperatures from 26 to 34℃. At 26℃, 48 h after treatment, scopoletin and BDMC showed the strongest acaricidal activity against T. cinnabarinus with the LC50 values of 0.1884 and 0.3376 mg/mL, respectively. The mathematical models of the relationship between LC50 (y) and temperature (x) were simulated: for scopoletin, y1= 0.006x12-0.278x1+3.403; for BDMC, y2=0.007x22-0.354x2+4.826. Based on the differential coefficients of above models, the optimal acaricidal activities of scopoletin and BDMC were obtained at 23.2 and 25.3℃, respectively, with the LC50 values of 0.1828 and 0.3504mg/mL, respectively. It is so concluded that the toxicities of scopoletin and BDMC exhibit a positive temperature coefficient first and then exhibit a negative temperature coefficient with increasing temperature.
    Functional response of the parasitoid Sclerodermus sp. (Hymenoptera: Bethylidae) to the third instar larvae of host Monochamus alternatus (Coleoptera: Cerambycidae)
    ZHANG Yan-Long, YANG Zhong-Qi, WANG Xiao-Yi, ZHANG Yi-Nan, WU Cheng-Jin, MA Sheng-Fu, LU Zhi-Gui
    2012, 55(4):  426-434. 
    Abstract ( 3582 )   PDF (14139KB) ( 1265 )     
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    In order to evaluate the control effects of Sclerodermus sp. (Hymenoptera: Bethylidae) on the 3rd instar larvae of Monochamus alternatus (Coleoptera: Cerambycidae), a method of functional response was used to test the effects of preying on hosts and parasitization, and the density effect of Sclerodermus sp. was also studied. The results showed that when the density of the bethylid wasps was 1 per cylinder, the functional response of Sclerodermus sp. preying on the 3rd instar larvae of M. alternatus could be described by Holling Ⅱ model. The maximum quantity of hosts killed by preying on hosts by one bethylid wasp was 9.48, and the average value was 3.75. The functional response of parasitization fitted Holling Ⅰ model, in which the threshold limit of the number of hosts is 4. The searching effects of preying on hosts and parasitization attenuated linearly with the increase of host density. When the density of M. alternatus larvae was 30 per cylinder, with the density of wasps increasing, the functional response of parasitization and preying on hosts increased linearly while the searching effect attenuated. A model between ratio of bethylids to beetle larvae and total lethality showed that when the ratio of the bethylids to larvae was 0.9805 (approximately 1∶1), the mortality of M. alternatus larvae was the maximal. The results suggest that Sclerodermus sp. is an effective natural enemy to M. alternatus larvae. This study provides essential data and methods for evaluating control ability of Sclerodermus sp. on M. alternatus, and also supplies theoretical basis for its release amount in the field.
    Correlative analysis between contents of nutrients and secondary substances in damaged masson pine needles and population parameters of Dendrolimus kikuchii (Lepidoptera: Lasiocampidae)
    ZHOU Suo, CHEN Shun-Li, CHEN De-Lan, WU Hui, ZHANG Fei-Ping, ZHANG Chao-Ju, DU Rui-Qing
    2012, 55(4):  435-443. 
    Abstract ( 3319 )   PDF (1420KB) ( 1040 )     
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    In order to explore the effects of variation in chemical substances in damaged masson pine (Pinus massoniana) needles, on population dynamics of Dendrolimus kikuchii, D. kikuchii larvae were reared with masson pine needles with different damage degrees caused by the pest in the laboratory, its population parameters and contents of nutrients and secondary substances in damaged masson pine needles were measured, and the integrated correlation coefficient was adopted for data analysis. The results showed that with the damage increasing in masson pine needles caused by D. kikuchii larvae, flavones in needles increased accordingly, while contents of soluble sugars, polysaccharides and proteins decreased. The average developmental duration and mortality of D. kikuchii larvae increased with the damage increasing. No significant correlation was found between the variation in contents of tannins or total phenols and the developmental duration or mortality of each instar larvae. There were significantly direct and comprehensive correlations between contents of nutrients and secondary substances of masson pine needles and the developmental duration or mortality of each instar larvae excluding 6th instar larvae. With the damage increasing in masson pine needles caused by D. kikuchii larvae, all parameters including body weight of 7th instar larvae, needle consumption, pupal weight, emergence rate, female ratio and fecundity in D. kikuchii population feeding the damaged masson pine needles decreased. No significant correlation was found between the variation in contents of tannins or total phenols and population parameters of D. kikuchii larvae. The results suggest that the contents of nutrients and secondary substances in masson pine needles dramatically influence the population parameters of D. kikuchii, with the importance sequence from high to low: soluble sugars>proteins>polysaccharides>flavones. Contents of tannins and total phenols seem to have no significant influence.
    Food plants and foraging behaviors of Xylocopa appendiculata (Hymenoptera, Apidae) in Luoyang, Henan Province, central China
    HE Chun-Ling, LI Xue-Ping, ZHANG Hong-Xiao
    2012, 55(4):  444-456. 
    Abstract ( 4186 )   PDF (14430KB) ( 1425 )     
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    【Aim】 For the further development and utilization of the Xylocopa resources, it is necessary to know the food plants and foraging behaviors of X. appendiculata. 【Methods】 From March to October of the past three years (2009-2011), the floral resources of X. appendiculata and its foraging behaviors were observed by visual observation and photographing in fields in Luoyang, Henan Province, central China. Characteristics of plant species utilized as its food resources were recorded. The size of holes in the corolla tube chewed by robbers was measured. 【Results】 In natural habitats, there were 52 plant species in 27 different families in Luoyang, Henan Province, central China visited by X. appendiculata, and 25 of the species were its major plant resources. The species proportions of Caprifoliaceae and Leguminosae families were dominant (17.31% and 15.38% of the total plant species visited, respectively). Sixteen of the 43 plant species were robbed by X. appendiculata, accounting for 30.77% of its visited plants. X. appendiculata prefers flowers which are usually medium-sized, zygomorphic, and purple, yellow, or white colored. Significant variations were found in size of robbing holes and flower visiting frequency of X. appendiculata in different species. Size of robbing holes in Clerodendrum bungei were the maximal (9.43±1.91 mm in diameter), while minimal (3.46±0.98 mm in diameter) in Kolkwitzia amabilis. Flower visiting frequency in Lagerstroemia indica was the highest, 25.71±2.36 flowers per minute; and the duration of each visit and interval time of X. appendiculata between two flowers in Althaea rosea were the highest, 5.89±3.34 s per flower and 2.63±2.04 s between two flowers, respectively. 【Conclusion】 X. appendiculata foraging is characterized by a wide range of food plants and long seasons of activity. Significant variations exist in its foraging behaviors and foraging frequency on different plants.
    Analysis of genetic polymorphism of Athetis lepigone (Lepidoptera: Noctuidae) populations from China based on mtDNA COⅠ gene sequences
    ZHU Yan-Bin, MA Ji-Fang, DONG Li, LI Li-Tao, JIANG Jing-Yu, LI Zhi-Hui, DONG Zhi-Ping, DONG Jin-Gao, WANG Qin-Ying
    2012, 55(4):  457-465. 
    Abstract ( 4168 )   PDF (4914KB) ( 1682 )     
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    Athetis lepigone is a newly recorded insect pest of summer corn seedlings, which was first found in Hebei province in 2005 and broke out on a large scale in Hebei, Henan, Shandong, Shanxi, Anhui and Jiangsu in July, 2011. In order to explore its outbreak mechanisms at the population level, we analyzed the genetic diversity of A. lepigone populations from four provinces of China using mitochondrial cytochrome oxidase subunit Ⅰ (mtCOⅠ) gene. The partial sequences (658 bp) of mtCOⅠ gene in 19 geographic populations of A. lepigone were sequenced and analyzed through homologous sequence alignment. We also carried out the mtCOⅠ haplotype diversity analysis and Tajima’s D test, and constructed the Neighbor-Joining (N-J) phylogenetic tree and haplotype network of COⅠ haplotypes of different populations using DnaSP 5.0 and Arlequin 3.5, respectively. The results showed that there were 17 haplotypes and 18 variable sites in the total 203 individuals. The analysis of phylogenetic tree and haplotype network based on 17 mtCOⅠ haplotypes indicated that the polymorphism of mtCOⅠ haplotypes of A. lepigone populations from Hebei province was the highest among four provinces. The haplotypes of A. lepigone populations from Henan, Shanxi and Shandong were the same as those from Hebei population. However, the results of Tajima’s D test suggested that total populations did not experience obvious expansion in recent history. These results suggest that the level of gene flow among all populations of A. lepigone is high, and there is not obvious genetic differentiation among populations.
    Automatic recognition of insect sounds using MFCC and GMM
    ZHU Le-Qing, ZHANG Zhen
    2012, 55(4):  466-471. 
    Abstract ( 4893 )   PDF (899KB) ( 1179 )     
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    Insects produce various sounds when they are moving, feeding or calling. These sounds exhibit intraspecies similarity and interspecies differences, thus they can be used to discriminate species identities of insects. Automatic detection of insect species through sounds produced by the insects would be very meaningful in giving farm workers or forestry workers a convenient way to recognize insects. In this study we employed the sound parameterization techniques that are frequently used in the field of human speech recognition. Melfrequency cepstrum coefficients (MFCCs) were extracted from the sound samples after preprocessing, and Gaussian mixture model (GMM) was trained with these MFCC features. Finally, the unknown insect sound samples were classified by the GMM. The proposed method was evaluated in a database with acoustic samples of 58 different insect sounds. The method performed well in terms of both recognition rate and time performance. The average recognition accuracy was as high as 98.95%. The test results proved that sound parameterization techniques based on MFCC and GMM could be used to recognize insect species efficiently.
    Progress in the complete mitochondrial genomes of the Acari
    YUAN Ming-Long, WANG Jin-Jun
    2012, 55(4):  472-481. 
    Abstract ( 3544 )   PDF (1598KB) ( 1220 )     
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    Acari, including ticks and mites, is one of the most diverse group of arthropods. In this paper, we reviewed the research progress in the 28 sequenced complete mitochondrial genomes of acari species. These mitochondrial genomes have several marked features: (1) There is significant variation in the size of mitochondrial genomes among the 28 acari species, and the mitochondrial genome of Panonychus citri (13 077 bp) is the smallest among all sequenced arthropods; (2) The base composition of all acari mitochondrial genomes are biased toward A and T, with six species harboring reverse GC-skew values (positive value); (3) The base composition and the position, length, copy number of the A+T-rich regions vary greatly among the 28 acari species, of which four tetranychid species harbor the highest A+T content within acari and the shortest A+T-rich region (44-57 bp) among arthropods; (4) High gene rearrangements are found in acari mitochondrial genomes, especially in those of Acariformes, but the rearrangements are not correlated to high taxonomic ranks; (5) The tRNA genes in some species of Acariformes are extremely truncated, presenting atypical cloverleaf structures. We suggest that it is necessary to sequence more acari mitochondrial genomes aiming to investigate whether these tRNA genes lacking both D- and T-arms are functional or not, to analyze the molecular mechanisms of evolution in acari mitochondrial genomes, and to carry out the acari mitochondrial transcriptome studies.
    Phylogenetic position of yeast-like symbiotes from three rice planthoppers (Homoptera: Delphacidae) based on 18S rDNA and ITS-5.8S rDNA sequences
    ZHOU Yan-Yan, DONG Sheng-Zhang, BAI Xu, YU Xiao-Ping
    2012, 55(4):  482-487. 
    Abstract ( 4217 )   PDF (5101KB) ( 1167 )     
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    In order to study the species status of yeast-like symbiotes (YLS) from three rice planthoppers (Laodelphax striatellus, Nilaparvata lugens and Sogatella furcifera) and the evolutionary relationship of YLS with insect hosts, the complete sequences of 18S rDNA and ITS-5.8S rDNA of YLS from the three planthoppers were determined. Sequence identity comparison of YLS from rice planthoppers was conducted based on 18S rDNA and ITS-5.8S rDNA sequences. The results showed that YLS of N. lugens has a higher identity to that of S. furcifera (98.91%) than to that of L. striatellus (95.74%) according to 18S rDNA sequences, but YLS of L. striatellus has a higher identity to that of S. furcifera (99.57%) than that to N. lugens (91.91%) according to the ITS-5.8S rDNA sequences. Phylogenetic analysis based on both 18S rDNA and ITS-5.8S rDNA showed that YLS from three rice planthoppers has no obvious identity to other known fungi. The results suggest that insect YLS have a close evolutionary relationship with hosts and form a taxonomic group different from other fungi.
    Evaluation of the effectiveness of conventional insecticides against the cowpea weevil, Callosobruchus maculatus (Coleoptera: Bruchidae), on four different substrate surfaces
    Vahid MAHDAVI, Moosa SABER, Samad VOJOUDI
    2012, 55(4):  488-492. 
    Abstract ( 3022 )   PDF (3128KB) ( 1174 )     
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    In pest management programs, the control of pests in structural facilities or sites, where processed food products are consumed or stored, requires the application of insecticides upon a variety of substrate surfaces. In order to determine the insecticidal effectiveness on different substrate surfaces, adults of the cowpea weevil, Callosobruchus maculatus (F.), were exposed to field recommended concentrations of chlorpyrifos, abamectin and deltamethrin insecticides. The results showed that abamectin caused mortality rates of 63.33%, 22.41%, 12.9% and 11.9% while deltamethrin caused mortality rates of 55%, 44.2%, 41.3% and 37.4% on glass, ceramic tile, plastic and paper disc surfaces, respectively. Exposures to chlorpyrifos led to 100% mortality in all surfaces. Probit analysis of data showed that LC50 values were 8.66, 13.6, 29.16 and 56.5 μg/mL for chlorpyrifos, 119.4, 446.2, 774.2 and 836.4 μg/mL for abamectin, and 1 008, 1 131, 1 210 and 1 336 μg/mL for deltamethrin on the glass, ceramic tile, plastic and paper disc surfaces, respectively, based on formulated materials. It is concluded that chlorpyrifos is the most toxic insecticide to the cowpea weevil, but that its toxicity was reduced in the glass, ceramic tile, plastic and paper disc surfaces in sequence.
    Morphological observation on adult Dermatophagoides pteronyssinus (Acari: Pyroglyphidae) with scanning electron microscope
    ZHAO Xue-Ying, LIU Xiao-Yu, LI Ling, SUN Xin, LIU Zhi-Gang
    2012, 55(4):  493-498. 
    Abstract ( 3953 )   PDF (6366KB) ( 1481 )     
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    【Aim】 The external morphology including the gnathosoma, idiosoma, external genitalia and legs of Dermatophagoides pteronyssinus was observed by using scanning electron microscopy (SEM). 【Methods】 D. pteronyssinus mites were collected from the dust of beds and pillows, and the living adult mites were isolated using the stereoscope and observed with SEM. 【Results】 SEM photographs showed that the cheliceraeare clamp-like and palps flat. Cuticle is covered with fine striations like fingerprint, with distance between striations less than 2 μm. Oviporus of female genitalia is located at the center of the ventral surface of the idiosoma. The male genitalia has a pair of leaflike genital folds. Anus is a longitudinal hole, with two anal suckers in the male. The end of each tarsus of female has a pulvillus, and the tarsus of leg Ⅳ of the male has two suckers. 【Conclusion】 The observations on D. pteronyssinus provide more evidence for identification of dust mites.