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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 2016, Volume 59 Issue 10
For Selected: View Abstracts Toggle Thumbnails
  • RESEARCH PAPERS
    Location and expression of AChE in apoptotic midgut cells of Nilaparvata lugens (Hemiptera: Delphacidae) induced by host rice resistance
    WANG Si-Qi, CHEN Jun, ZHANG Juan-Juan, YANG Zhi-Fan
    2016, 59(10):  1033-1042.  doi:10.16380/j.kcxb.2016.10.001
    Abstract ( 1489 )   PDF (13126KB) ( 634 )     
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    【Aim】 The brown planthopper, Nilaparvata lugens, is one of the most destructive pests of rice. This study aims to investigate the relationship between acetylcholinesterase (AChE) and the apoptosis in midgut cells of N. lugens induced by host rice resistance. 【Methods】 Primary cells were isolated from the midgut of the 4th instar nymph (biotype Ⅰ) of N. lugens. The first-generation subculture cells were treated with juice from rice seedlings with different resistance levels. Subcellular localization and expression of AChE were detected by using cell immunohistochemistry and real-time fluorescence quantitative PCR techniques, respectively. 【Results】 No green fluorescent signals representing apoptotic nuclei were detected in the untreated control cells, but these cells exhibited few signals in immunohistochemistry reaction, suggesting a basal expression level of AChE within the cells. The cells treated with the juice from seedlings of the susceptible rice variety TN1 and two resistant rice varieties B5 and TKM-6 displayed apoptosis with the apoptotic rate of 8%, 65% and 85%, respectively. Immunohistochemistry reaction revealed that all apoptotic cells showed stronger signals representing overexpression and accumulation of AChE in the cytoplasm. AChE assembled around the nuclei instead of shifting to apoptotic bodies in the late apoptotic stage. The data from real-time fluorescence quantitative PCR showed 29.9-, 18.4- and 8-fold over-expression of AChE in cells treated with the juice from seedlings of TKM-6, B5 and TN1, compared with that in the control cells, which was consistent with the results from the immunohistochemistry detection. 【Conclusion】 The results confirm that host rice resistance is positively correlated with apoptosis in midgut cells of N. lugens, and AChE is overexpressed in apoptotic cells. These findings provide some valuable information for understanding the interaction mechanism of N. lugens and host rice, promoting breeding of novel resistant rice varieties and developing effective control strategies.
    Regulation of the expression of fibroin light chain gene BmFib-L by bmomiR-375-3p in Bombyx mori
    FAN Yang-Yang, QIAN Ping, SHEN Xing-Jia, WANG Xin, JIANG Tao, TANG Shun-Ming
    2016, 59(10):  1043-1049.  doi:10.16380/j.kcxb.2016.10.002
    Abstract ( 1221 )   PDF (1858KB) ( 536 )     
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    【Aim】 To explore the regulatory function of Bombyx mori microRNAs (bmo-miRNAs) on the expression of fibroin light chain gene BmFib-L and P25 protein gene BmP25. 【Methods】 BmFib-L and BmP25 mRNA 3′UTRs were used as targets to predict the potential bmo-miRNAs with target sites on BmFib-L and BmP25 by the online RNAhybrid software from the previously obtained 29 differentially expressed bmo-miRNAs in the posterior silk gland of the 4th and 5th instar larvae of B. mori. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) method was employed to analyze the expression levels of the potential bmo-miRNAs and their target genes BmFib-L and BmP25 in the posterior silk gland of the 4th and 5th instar larvae and in different tissues of the 5th instar day-3 larvae of B. mori. The regulatory function of potential bmo-miRNAs on the expression of BmFib-L and BmP25 was validated by using the dual-luciferase reporter assay system in BmN cells. 【Results】 One bmo-miRNA, miR-375-3p (previously named bmo-miR-375*), was predicted to have target sites at the mRNA 3′UTRs of both BmFib-L and BmP25. The bmo-miR-375-3p and its potential targets BmFib-L and BmP25 all showed comparatively high expression levels in the posterior silk gland, suggesting that in the posterior silk gland there are the spatial-temporal conditions for bmo-miR-375-3p to regulate the expression of BmFib-L and BmP25. When bmo-miR-375-3p recombinant expression vector co-transfected with expression vector of BmFib-L 3′UTR fused firefly luciferase report gene (luc) in BmN cells, the expression level of luc was significantly down-regulated. When bmo-miR-375-3p expression vector co-transfected with expression vector of BmP25 3′UTR fused luc report gene in BmN cells, however, the expression level of luc was slightly but not significantly down-regulated. 【Conclusion】 Bmo-miR-375-3p down-regulates the expression of BmFib-L gene significantly, but has no significant effect on the expression of BmP25.
    Cloning and expression analysis of cytochrome CYP9E2 gene in the Chinese honeybee, Apis cerana cerana
    JIANG Wu-Jun, HE Xu-Jiang, WANG Zi-Long, YAN Wei-Yu, ZENG Zhi-Jiang, WU Xiao-Bo
    2016, 59(10):  1050-1057.  doi:10.16380/j.kcxb.2016.10.003
    Abstract ( 1794 )   PDF (3409KB) ( 586 )     
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    【Aim】 The objective of this study is to clone the coding region sequence of cytochrome CYP9E2 gene of the Chinese honeybee, Apis cerana cerana, and to analyze its expression profiles in workers, which will contribute to our understanding on the biological function of this gene. 【Methods】 Total RNAs were extracted from the dissected midgut tissues of A. cerana cerana foragers, and the coding sequence of CYP9E2 gene of A. cerana cerana was cloned using RT-PCR. The nucleotide and deduced amino acid sequences of the gene were analyzed using bioinformatics software. The relative expression levels of the gene in heads and midguts of the newly emerged workers, nurses, guarders and foragers were compared via quantitative real-time PCR (qRT-PCR). The relative expression levels of the gene between workers fed with flumethrin and the ones fed with 30% sucrose (control) were also compared. 【Results】The full length mRNA sequence of CYP9E2 gene of A. cerana cerana (named AcCYP9E2) is 1 600 bp (GenBank accession number: KX394629). Its coding region is 1 494 bp, which encodes 497 amino acids. The molecular weight and isoelectric point of the encoded protein are 57.026 kD and 8.32, respectively. The phylogenetic tree analysis showed that AcCYP9E2 of A. cerana cerana was firstly clustered with CYP9E2 genes from A. mellifera and A. florea. The qRT-PCR results showed that the relative expression level of AcCYP9E2 was different among the four worker bee groups, while the relative expression levels of AcCYP9E2 in the heads and midguts of foragers were both significantly higher than those of the newly emerged workers, nurses and guarders (P<0.05). The relative expression level of AcCYP9E2 was significantly higher in the midgut than that in the head in all the four worker bee groups (P<0.05), and the relative expression level of AcCYP9E2 in the midgut of the flumethrin-treated groups was significantly higher than that in the control group (P<0.05). 【Conclusion】 These results suggest that AcCYP9E2 may be involved in the metabolism process and detoxification of exogenous substances in the body of A. cerana cerana.
    Identification, characteristics and distribution of microsatellites in the whole genome of Anopheles sinensis (Diptera: Culicidae)
    WANG Xiao-Ting, ZHANG Yu-Juan, HE Xiu, MEI Ting, CHEN Bin
    2016, 59(10):  1058-1068.  doi:10.16380/j.kcxb.2016.10.004
    Abstract ( 1541 )   PDF (3185KB) ( 482 )     
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    【Aim】 Anopheles sinensis is an important malaria vector in China and southeastern Asia. The study aims to identify and analyze the simple sequence repeats (SSRs, also called as microsatellites) and to annotate the functions of SSR-containing genes in the whole genome of An. sinensis, so as to provide the basis for the selection of molecular genetic markers in An. sinensis and to lay a foundation for further studies of the comparative genomics of SSRs in insects. 【Methods】 MISA program was used to identify SSRs in the An. sinensis genome, and Excel 2010 was used to count the length of SSRs identified. Perl scripts were written in the study to calculate the SSRs base content based on the SSR sequence and to map the SSRs to the genome based on the SSR location information from SSR identification. WEGO was used to carry on the GO function annotation of SSR-containing genes in An. sinensis and An. gambiae. 【Results】 A total of 105 981 SSRs were identified in the An. sinensis genome, with the genomic density of 365.5 SSRs per Mb. Out of these SSRs, 100 391 (occupying 94.7%) are perfect SSRs, and the remaining 5 590 (5.3%) are compound SSRs. The mononucleotide SSRs (58 837, 55.5%) are the most abundant, followed by dinucleotide SSRs (30 345, 28.6%), trinucleotide SSRs (15 104, 14.3%), tetranucleotide SSRs (1 530, 1.4%), penanucleotide SSRs (121, 0.1%) and hexanucletide SSRs (44, less than 0.1%). The (A)n SSRs are the most predominant, followed by (AC)n, (AG)n, (C)n, (AGC)n, (ATC)n, (ACG)n and (ACC)n, and each of these types has more than 2 000 SSRs. The SSRs of 10-20 bp length occupy 87.1% of the total. Except that the GC-content (53%) of trinucleotide SSRs is slightly higher than their AT-content, the AT-content (63%) of other SSRs is obviously higher than the GC-content (37%). And 90 632 (85%) SSRs are located in the intergenic region, and 15 349 (15%) SSRs in the gene region, of which 2 782 (3%) SSRs are in the exon region and 12 567 (12%) SSRs in the intron region. The comparison of GO functional annotation of SSR-containing genes in An. sinensis and An. gambiae showed that the percentages of all subcategories of genes are basically similar with each other; the percentage of electron carrier genes in An. sisensis (occupying 0.9%), however, is significantly higher than that in An. gambiae (0.1%). 【Conclusion】 This is the first systematical research of SSRs in whole genomes of mosquito species. The study lays an important basis for the selection of SSRs as biomarkers to carry on the studies of population genetics, genetic variation, the genetic location and regulation mechanisms of functional genes, as well as the studies on the diversity and evolution of SSRs in insects.
    Effects of protease inhibitors on the activities of midgut proteases of larval Grapholitha molesta (Lepidoptera: Tortricidae)
    HAO Ai-Ping, SUN Cong, ZHAN En-Ling, WU Jun-Xiang, LI Yi-Ping
    2016, 59(10):  1069-1078.  doi:10.16380/j.kcxb.2016.10.005
    Abstract ( 1296 )   PDF (2018KB) ( 540 )     
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    【Aim】 Grapholita molesta (Busck) is a fruit pest that causes extremely serious damage. Intestinal protease plays an important role in its growth and development processes. To provide new ideas for using protease inhibitors to control pest insects, the effects of the optimum pH, different inhibitors and activators on the midgut protease activities of G. molesta larvae were studied in this study. 【Methods】 Enzyme fluids were extracted from the midgut of the 3rd instar larvae of G. molesta. Using enzyme specificity substrates, the optimum pH of the midgut proteases of G. molesta larvae was detected in three different buffer solutions (ddH2O as the CK), the effect of protease inhibitors and activators on the midgut protease activities were determined. At the same time, the effect of the different protease inhibitors (PMSF, TLCK, TPCL and STI) on the midgut protease activities was also determined when G. molesta larvae were fed with them. 【Results】 The optimum pH levels of midgut total protease of G. molesta larvae in the three buffers Tris-HCl, KH2PO4/NaOH and glycine/NaOH were 10.5, 11.0 and 11.0, respectively, those of high-alkaline trypsin were 10.5, 11.0 and 11.0, respectively, those of low-alkaline trypsin were 8.5, 9.0 and 9.0, respectively, and those of chymotrypsin were 8.5, 9.0 and 9.5, respectively. Of the five protease inhibitors (DTT, PMSF, TLCK, TPCL and STI), except that TLCK activated the chymotrypsin activity, the other inhibitors inhibited the activities of all proteases; and the higher the inhibitor concentration was, the more significant the inhibitory effects were. The inhibition effects of the inhibitor DTT on the activities of total protease and low-alkaline trypsin were greater than those of the other inhibitors. Of the four protease activators (MgCl2, CaCl2, EDTA and EGTA), MgCl2 inhibited the activities of total protease and chymotrypsin but activated the trypsin activity, CaCl2 activated the activities of casein enzyme and low-alkaline trypsin but inhibited the activities of high-alkaline trypsin and chymotrypsin, EDTA inhibited the activities of the four proteases, and EGTA inhibited the activities of the other three proteases except high-alkaline trypsin. When G. molesta larvae were fed with different protease inhibitors (PMSF, TLCK, TPCL and STI), all inhibitors could inhibit the activities of the four proteases, with obviously different inhibitory activities at different sampling time points. The inhibitory effects of STI (50 μg/mL) on the activities of the four proteases were greater than those of the other inhibitors; and the higher the inhibitor concentrations were, the more significant the inhibitory effects were. In three experimental treatments with 10, 20 and 50 μg/mL STI, sampling at 4 h post treatment the activities of the four proteases increased, and the increased levels was related to the concentration of STI. The protease activity went to its lowest level in the 20 μg/mL STI experimental treatment at 48 h post treatment, and the 50 μg/mL STI experimental treatment at 60 h post treatment, and the inhibitor STI showed a highly sustainable efficiency. 【Conclusion】 This study indicates that protease inhibitors have certain inhibitory effects on the protease activities in larval midgut of G. molesta, and the inhibitor STI has a great application value in pest control.
    Cell proliferation and programmed cell death in the hypopharyngeal gland of Apis cerana cerana (Hymenoptera: Apidae) workers during postembryonic development
    LI Zhao-Ying, YU Hong-Mei, SUN Yan, SUN Jing
    2016, 59(10):  1079-1085.  doi:10.16380/j.kcxb.2016.10.006
    Abstract ( 1172 )   PDF (1316KB) ( 419 )     
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    【Aim】 The hypopharyngeal gland of honeybee is responsible for secreting royal jelly. This study aims to understand the postembryonic development of the hypopharyngeal gland of workers of the Chinese honeybee, Apis cerana cerana. 【Methods】 The postembryonic developmental process and structure characteristics of the hypopharyngeal gland of A. c. cerana workers were comparatively studied by using histological, 5-bromo-2-deoxyuridine (BrdU) incorporation and the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) techniques. 【Results】 The results showed that the hypopharyngeal gland of A. c. cerana workers is originated from evaginations of the dorsal portion of the mouthpart during the prepupal stage, and extensive proliferation in the hypopharyngeal gland is detected only in the first three days of pupal development. Proliferative nuclei disappear on the 7th day of pupal development. The acinis divide on the 5th day of pupal development. In late pupae, the acinis of hypopharyngeal gland form but has not grown to full size. The hypopharyngeal gland is highly developed in nursing workers. Programmed cell death (PCD) predominates in older foraging workers. 【Conclusion】 This study reveals the cell proliferation and apoptosis pattern of the hypopharyngeal gland of A. c. cerana workers during postembryonic development, providing an essential foundation for studying the development and function of insect hypopharyngeal gland.
    Analysis of the diversity of microorganisms in the wax secreted by the Chinese white wax scale insect, Ericerus pela (Chavannes) (Hemiptera: Coccidae)
    WANG Xue-Qing, YU Shu-Hui, SUN Tao, ZHAO Zun-Ling, CHEN Xiao-Ming, YANG Pu
    2016, 59(10):  1086-1092.  doi:10.16380/j.kcxb.2016.10.007
    Abstract ( 1534 )   PDF (1380KB) ( 542 )     
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    【Aim】 This study aims to explore the diversity of microorganisms in the wax secreted by male nymphs of Ericerus pela (Chavannes), to analyze the bacterial and fungal species and to compare the microorganism change in the wax layers with different thicknesses (the wax layer thickens with the developmental stage of male nymphs). 【Methods】 The MiSeq high-throughput sequencing method was employed to sequence the 16S rRNA of bacteria and the internal transcribed space (ITS) of fungi in the wax secreted by male nymphs of E. pela at different developmental stages. The bacterial and fungal OTUs, richness and alpha diversity was calculated and analyzed with the Mothur software. 【Results】 According to 470 OTUs obtained from 3 bacterial samples, 18 phyla, 30 classes, 92 families and 173 genera were identified. Meanwhile, 3 phyla, 15 classes, 43 families and 68 genera were identified from 264 OTUs obtained from 2 fungal samples. As the dominant bacteria, Comamonas accounted for 79.79%, 41.61% and 46.86% of the total bacteria in the wax secreted by male nymphs at the early, middle and late stages, respectively. Cladosporium and Cryptococcus were two important components of fungi in the wax, accounting for 17.01% and 60.84% fungi in the wax secreted by male nymphs at the early and late stages, respectively. 【Conclusion】 There are some differences in bacterial and fungal communities in the wax secreted by male nymphs of E. pela at different developmental stages. The bacterial diversity in the wax layers increases initially and then decreases with the developmental stage of male nymph, while the fungal diversity in the wax layers decreases with the wax thickening.
    Inhibition of cellular proliferation and induction of necrosis in Ofh cells of Ostrinina furnacalis (Lepidoptera: Pyralidae) by momordicin I and charantin B
    LUO Jian-Feng, LIU Huan, GUO Zi-Jun, WANG Guo-Cai, LING Bing
    2016, 59(10):  1093-1102.  doi:10.16380/j.kcxb.2016.10.008
    Abstract ( 1159 )   PDF (5778KB) ( 495 )     
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    【Aim】 To ascertain the toxic effect of momordicin I and a new compound (charantin B) from ethanol extracts of Momordica charantia leaves on larval Ostrinina furnacalis hemocytes (Ofh), and to illuminate its action mechanism as well. 【Methods】 The inhibition effects of momordicin I, momordicin II, charantin B and azadirachtin A on Ofh cells were compared by using CCK-8 assay. The effects of momordicin I and charantin B on Ofh cell morphology structure were observed by using inverted phase contrast microscopy and fluorescence microscopy, and the induced necrosis effects on Ofh cells were studied by using trypan blue staining and flow cytometry (FCM) technologies. 【Results】 Momordicin I, momordicin II and charantin B had apparent inhibition effects on Ofh cell proliferation, with the IC50 values of 7.566, 24.340 and 8.514 μg/mL, respectively, at 36 h after treatment. The cytotoxicity of momordicin I and charantin B were significantly higher than that of momordicin II and azadirachtin A. Using inverted phase contrast microscopy, we found that after exposure to momordicin I and charantin B, Ofh cell shapes changed to circular and swelling increased, and the cellular membrane bubbled, suggesting that both momordicin I and charantin B could destruct cell morphology structure. Further research indicated that the mortality rates of cells in the groups treated with 8 μg/mL momordicin I and charantin B were significantly higher than that of the control group at 12-48 h after treatment, and in a time-dependent manner, indicating that the cytotoxicity of momordicin I is significantly higher than that of charantin B. Fluorescence microscopy observation revealed that nuclear morphology was irregular, the cell membrane dissolved and the nucleus appeared to be severely damaged after AO/EB staining, and cells exhibited a non-uniform orange-yellow fluorescence after treatment with 8 μg/mL momordicin I and charantin B, showing a typical characteristic of necrosis. Flow cytometry analysis showed that Ofh cells treated with momordicin I and charantin B were dramatically induced to undergo necrosis, and the total cell necrosis rates were 74.92%±2.02% and 49.77%±1.69%, respectively, after 36 h treatment with 8 μg/mL momordicin I and charantin B. 【Conclusion】 Momordicin I and charantin B have significant inhibition effects on cell proliferation and can induce necrosis, which may account for the antifeedant effect of momordicins on O. furnacalis and the inhibition of growth and fecundity of O. furnacalis treated by momordicins.
    Effects of varied photoperiods on the mating and oviposition of Brithys crini (Lepidoptera: Noctuidae) adults
    QIU Xiao-Fang, XIE Jian-Kun, WU Li-Ping, YU Qin, ZHANG Meng-Meng, WANG Guang-Yao, XU Shao-Hui, TU Xiao-Yun
    2016, 59(10):  1103-1114.  doi:10.16380/j.kcxb.2016.10.009
    Abstract ( 1288 )   PDF (1695KB) ( 553 )     
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    【Aim】 Brithys crini (Fabricius) mainly feeds on Amaryllidaceae plant, including Zephyranthes candida. Previous research showed that photoperiod has significant effects on the circadian rhythm of mating and oviposition, mating percentage and the number of eggs laid of B. crini. This study aims to investigate the effects of intermittent light length, the position of dark period and non-24 h light-dark cycle on its mating and oviposition. 【Methods】 The mating and oviposition were observed in intermittent light lengths (20, 10, 5, 1 and 0 min), the position of dark period (D10: 00 -22: 00, D12: 00 -24: 00, D14: 00 - 02: 00 and D16: 00 -04: 00) and non-24 h light-dark cycle (4L∶4D, 8L∶8D, 24L∶24D and 48L∶48D) under the climate cabinet conditions (white fluorescent light, light intensity about 500 lx). 【Results】 When intermittent light lengths were 20, 10, 5, 1 and 0 min, the numbers of mated adults were 0, 3, 10, 14 and 11, and the numbers of paired adults were 25, 29, 31, 39 and 26, respectively. The numbers of mated adults in 20 and 10 min groups were significantly different from that of the control group (0 min). The numbers of eggs laid per mated female were insignificantly different among groups (354.67, 322.30, 339.57 and 310.45 eggs for 10, 5, 1 and 0 min group, respectively). The numbers of mated adults were 13, 18, 15 and 12, and the numbers of paired adults were 16, 19, 17 and 16 in D10: 00-22: 00, D12: 00-24: 00, D14: 00-02: 00 and D16: 00-04: 00 groups, respectively, and there was no significant difference among treatment groups. The number of eggs laid per mated female was insignificantly different among treatment groups (516.15, 527.28, 495.53 and 458.50 eggs in D10: 00-22: 00, D12: 00-24: 00, D14: 00-02: 00 and D16: 00-04: 00 groups, respectively). The initiation time and peak time of mating and oviposition varied with the position of dark period. The numbers of mated adults were 16, 15, 14 and 14, and the numbers of paired adults were 18, 16, 14 and 16 in 4L∶4D, 8L∶8D, 24L∶24D and 48L∶48D groups, respectively, and there was no significant difference among treatment groups. The number of eggs laid per mated female was significantly different among groups (590.56, 559.67, 497.21 and 419.29 eggs in 4L∶4D, 8L∶8D, 24L∶24D and 48L∶48D groups, respectively). 【Conclusion】 These results reveal that the mating and oviposition behaviors of B. crini occur mainly in the dark period. The adults would not mate when the dark period is shorter than 40 min. The position and length of dark period have influences on the mating and oviposition of B. crini.
    Locomotive behavior of Henosepilachna vigintioctopunctata (Coleoptera: Coccinellidae) adults moving on ceiling substrata
    HUA Deng-Ke, GUI Lian-You, Gilles BOITEAU, LUO Jie
    2016, 59(10):  1115-1122.  doi:10.16380/j.kcxb.2016.10.010
    Abstract ( 1310 )   PDF (4585KB) ( 440 )     
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    【Aim】 This study aims to elucidate the locomotive behavior of adults of the 28-spotted potato ladybird, Henosepilachna vigintioctopunctata (Fabricius) moving on ceiling substrata, so as to provide references for pneumatic control technology to be developed and used in prevention and control of agricultural insect pests in China. 【Methods】 Based on the observation with a Sony camera the locomotive behavior parameters of adult H. vigintioctopunctata moving on ceiling substrata were determined, and the relationship between velocity and stride length, stride frequency and duty factor was analyzed, respectively. 【Results】 The results showed that H. vigintioctopunctata adults moved at a speed of 3.77-19.32 mm/s, with a stride length of 2.63-4.51 mm, and a stride frequency of 1.32-4.74 Hz on ceiling substrata. The stride length and stride frequency were both significantly affected by speed and increased with increasing velocity, but stride length changed less than stride frequency. The duty factors of each leg were significantly affected by speed and decreased with increasing velocity. In one stride period, the time of the transfer phase was much less than that of the support phase. 【Conclusion】 H. vigintioctopunctata adults increase their velocity largely by increasing their stride frequency, compared with the effects of stride length.
    Interactions of Camellia meiocarpa, Curculio chinensis (Coleoptera: Curculionidae) and a rodent (Rodentia: Muridae) in oil tea (Camellia meiocarpa) farm in Yiyang, Hunan, South Central China
    LI Zhi-Wen, SUN Han-Song
    2016, 59(10):  1123-1132.  doi:10.16380/j.kcxb.2016.10.011
    Abstract ( 1422 )   PDF (1515KB) ( 642 )     
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    【Aim】 The camellia weevil, Curculio chinensis Chevrolat, is an important pest attacking fruits of oil tea Camellia, an endemic genus to China, and causes tremendous fruit drop of its host plants. In the study area, the weevil larvae and its host (Camellia meiocarpa) fruits are strongly preyed by a rodent. To provide theoretical basis for scientific prevention and control of the weevil pest, we explored the complicated interactions among Camellia meiocarpa, Curculio chinensis and the rodent, and their behavioral mechanisms. 【Methods】 During the fruit drop season, 6 161 dropped fruits of C. meiocarpa were collected systematically from a farm in Heshan District, Yiyang City, Hunan Province, the damaged situation of each fruit caused by the weevil C. chinensis or the rodent was recorded, and the length, diameter and pericarp thickness of each fruit were also measured. The relationships between the weevil infestation rate and fruit traits such as the length, diameter and pericarp thickness of fruits as well as the correlation between the weevil mortality and the survey date were analyzed through linear regression, and the difference in fruit size between weevil-infested and non-weevil-infested fruits preyed by rodents was analyzed by independent samples t test. 【Results】 The weevil-infested fruit drop started on July 2 and lasted till fruits were harvested, and the peak of weevil-infested fruit drop was from August 16 to August 23 in 2013. Rodent predation was throughout the fruit drop season, and its peak was as the same as that of the weevil-infested fruit drop. The percentage of the 4th-5th instar larvae to the total number of weevil larvae in dropped fruits was 85.5%. There was no correlation between the weevil infestation rate and fruit diameter, and the weevil infestation rate had a significantly negative correlation with the pericarp thickness, but a significantly positive correlation with the benefit-cost ratio. The earlier the weevil infested fruits dropped, the heavier the fruit development was restricted, and the higher the weevil larval mortality was. The proportion of smaller fruits to the total number of rodent-preyed fruits was 76.9%, and all seeds in smaller fruits were depleted. The predation rate on weevil-infested fruits was 24.0%, and in these fruits, weevil-infested seeds were almost damaged by rodents, but most of non-weevil-infested seeds were not preyed. Of the rodent-preyed fruits, weevil-infested fruits were significantly larger than non-weevil-infested fruits in terms of fruit length and diameter. 【Conclusion】 The temporal pattern of fruit drop, weevil-infested fruit drop and rodent predation of C. meiocarpa fruits were investigated in this study. The results do not support the hypothesis of active defense, and the primary cause of the early fruit drop is a breakdown in the normal physiological process of fruit development caused by the feeding of C. chinensis larvae. There may be a trade-off between fruit size and pericarp thickness, the two contradictory selective pressures during the oviposition of female adults. In fact, this trade off is that between the fertility of parental females and the fitness of offspring larvae. The temporal pattern of oviposition of parental female adults will ultimately affect the fitness of their offspring larvae through affecting fruit development of their host plant C. meiocarpa. In the study area the rodent is an important natural enemy for C. chinensis, and it can accurately detect and prey on the weevil larvae in bigger fruits.
    Ultrastructure of larval compound eyes of Dicerapanorpa magna (Mecoptera: Panorpidae) and its implications for the evolution of stemmata of holometabolous larvae
    CHEN Qing-Xiao, HUA Bao-Zhen
    2016, 59(10):  1133-1142.  doi:10.16380/j.kcxb.2016.10.012
    Abstract ( 1750 )   PDF (19679KB) ( 449 )     
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    【Aim】 Mecoptera are unique in Holometabola in that their larvae possess a pair of compound eyes instead of stemmata, thus becoming ideal materials for uncovering the evolutionary relationship between compound eyes and stemmata in insects. This study aims to elucidate the structural features of the compound eyes of larval Mecoptera and to provide evidence for exploring the evolutionary relationship between the compound eyes of larval Mecoptera and the stemmata of other holometabolous larvae. 【Methods】 In this study, we observed the ultrastructure of the larval compound eyes of the scorpionfly Dicerapanorpa magna (Chou) using light, scanning and transmission electron microscopy and explored implications of the compound eyes of larval Mecoptera in the evolution of the stemmata of holometabolous larvae based on these structural features. 【Results】 The results showed that the compound eyes of larval D. magna are of the apposition type, each eye comprising more than 50 ommatidia. The ommatidium consists of a cornea, a crystalline cone, eight retinula cells, two primary pigment cells, and several secondary pigment cells. In the larval ommatidia, these retinula cells are arranged into four distal and four proximal cells. The rhabdomeres of the distal retinula cells extend up to surround the basal surface of the crystalline cone, so that the rhabdom assumes distally a funnel shape. 【Conclusion】 Layered retinula cells and the funnel-shaped rhabdoms are very likely the ground plan of the compound eyes in larval Mecoptera. These two characters are absent in imaginal Mecoptera, but present in many hemimetabolous insects, implying that the compound eyes of larval Mecoptera are likely homologous with those of hemimetabolous insects. We assume that the peculiar compound eyes of larval Mecoptera are the plesiomorphy of Holometabola, and the stemmata of other holometabolous larvae might be derived from compound eyes.  
    Progress in the integrated application of Chrysomya megacephala (Diptera: Calliphoridae)
    WANG Xiao-Yun, LI Kui, ZHU Fen, LEI Chao-Liang
    2016, 59(10):  1143-1150.  doi:10.16380/j.kcxb.2016.10.013
    Abstract ( 1254 )   PDF (1416KB) ( 564 )     
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    The blowfly Chrysomya megacephala is an important forensic indicator, resource insect and sanitary pest. It has a close association with human activities at various developmental stages. Distribution, classification and biological background of C. megacephala were briefly introduced in this review, and the forensic application, utilization of larvae to transform organic waste, active substances of larvae and pollination effects of adults were emphatically summarized. Risks caused by larvae and adults of C. megacephala and their probable handling methods were also discussed. New technical applications have broadened the aspects of forensic evidences by C. megacephala. C. megacephala larvae can efficiently consume organic waste such as manure, kitchen waste and sludge. Active substances of larvae will benefit the development of high-value-added products. Releasing of adult C. megacephala as pollinators is still restricted in controlled space although its adults are effective in pollination. The vector characteristic of C. megacephala would still be an obstacle for its wide utilization, and an integration of multiple methods might be the key to solve this problem.
    Contents of Vol. 59 Issue 10
    2016, 59(10):  1151-1151. 
    Abstract ( 799 )   PDF (434KB) ( 306 )     
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