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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 2019, Volume 62 Issue 4
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    Construction of a simple basal promoter for the research of transcription regulatory elements in the silkworm (Bombyx mori) at the cell level

    GU Jian-Jian, LIU Hong-Ling, LI Kai-Rong, MENG Zi-Wang, WANG Hui-Juan, SHEN Guan-Wang, ZHANG Yu-Jing, RUAN Yang, LIN Ying, XIA Qing-You
    2019, 62(4):  391-397.  doi:10.16380/j.kcxb.2019.04.001
    Abstract ( 684 )   PDF (1696KB) ( 277 )     
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    Aim This study aims to construct a simple basic promoter, which can be stably expressed in the silkworm (Bombyx mori) cells, so as to reflect the influence of single transcriptional regulatory element on gene promoter activity more accurately and lay a foundation for studying the transcriptional regulation of the silkworm and even other insects. Methods Based on the BmVgP78Mpromoter previously reported in our research group, which can be stably expressed in silkworm cells and hardly contains upstream transcriptional regulatory elements, interval sequences of a certain length and BrC-Z2 transcription factor binding motif (BrC-Z2 element, BrC-Z2E) that can respond to 20-hydroxyecdysone (20E) and enhance promoter activity were added to the upstream of BmVgP78Mby PCR technique. The cell transfection vectors were constructed by gene cloning technique, and the changes of promoter activity were detected by cell transfection technique and dual luciferase reporter gene system. Results A simple basal promoter named VgP78ML was constructed successfully with a 28 bp interval sequence added to the upstream of the BmVgP78Mpromoter, and proved to be a simple basic promoter to study target transcriptional regulatory elements. The verification test results showed that this simple basal promoter not only could be stably expressed in silkworm cells, but also was not affected by 20E and transcription factor BrC-Z2. When BrC-Z2E was linked to the upstream of this promoter, it could significantly respond to 20E and BrC-Z2 transcription factor, thereby regulating the expression of reporter gene. Conclusion VgP78ML can be used as a simple basic promoter to study the transcriptional regulation of genes in silkworm at the cell level. At the same time, its construction method also provides a reference for constructing simple basic promoter to study the transcriptional regulation in other species.
    Expression of BmToll9 genes responding to peptidoglycan and Staphylococcus aureus in larval Bombyx mori
    HUANG Yan-Ling, HUANG Shi-Yi, LI Shu-Qiang, HE Yan-Ying, CHEN Ze-Min, LIU Ji-Sheng
    2019, 62(4):  398-406.  doi:10.16380/j.kcxb.2019.04.002
    Abstract ( 644 )   PDF (1785KB) ( 245 )     
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    Aim Toll receptors of Toll signaling pathway, an important immune signaling pathway of insects, are essential to maintain immune response against invading exogenous microorganisms in insects. This study aims to explore the influence of peptidoglycan (PGN) and Staphylococcus aureus on the expression of the Toll receptor genes BmToll9-1 and BmToll9-2 in the silkworm, Bombyx mori. Methods PGN, the main component in cell wall of Gram-positive bacteria, and a Gram-positive bacterium S. aureus were respectively injected into the day-1 5th instar larvae of B. mori to induce the immune response. The relative expression levels of BmToll9-2 and BmToll9-1 in the midgut, epidermis, fat body and silk glands of the larvae at different time points post injection were detected by real-time quantitative PCR. Results After injection of PGN or S. aureus into the 5th instar larvae of B. mori, BmToll9-2 was differentially expressed at different time points and in different tissues. Injection of PGN or S. aureus induced up-regulation of the expression of BmToll9-2 in the midgut of the 5th instar larvae, achieving the best induction effect at 3 and 6 h post injection, respectively, and the induction effect of S. aureus was better than that of PGN. Injection of S. aureus induced up-regulation of the expression of BmToll9-2 in the epidermis, fat body and silk glands of the 5th instar larvae, achieving the best induction effects at 24, 6, and 24 h post injection, respectively. Injection of S. aureus also induced up-regulation of the expression of the homogenous BmToll9-1. Conclusion The expression of BmToll9 genes in different tissues of B. mori larvae is up-regulated after injection of PGN or S. aureus, suggesting that BmToll9 genes are involved in the immune response of B. mori against PGN and S. aureus.

    cDNA cloning and expression profiling of the c-Jun N-terminal kinase gene and its response to UV-A stress in Helicoverpa armigera (Lepidoptera: Noctuidae)
    LIU Xiao-Fei, MENG Jian-Yu, ZHAO Xiao-Chao, ZHANG Chang-Yu
    2019, 62(4):  407-417.  doi:10.16380/j.kcxb.2019.04.003
    Abstract ( 633 )   PDF (3243KB) ( 211 )     
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    Aim This study aims to clone the c-Jun N-terminal kinase (JNK) gene and to analyze the gene sequence and mRNA expression profiles in Helicoverpa armigera, so as to explore the function of JNK gene in the growth and development of the moth and its responses to UV-A stress. Methods The full-length cDNA of the JNK gene of H. armigera was cloned and identified using RT-PCR and RACE technique. The putative amino acid sequence of the JNK gene was analyzed by bioinformatics methods. The expression levels of the JNK gene in different developmental stages (egg, 1st-6th instar larva, pupa, female and male adult), adult tissues (head with antennae and compound eyes removed, thorax, abdomen, antenna, compound eye, legs, wing, midgut and ovary) and female adults exposed to UV-A for various time periods (0, 30, 60, 90, 120 and 150 min) were detected by real-time quantitative PCR (RT-qPCR). Results A JNK gene was cloned from H. armigera, and named HaJNK (GenBank accession no.: MH719009), which is 2 431 bp in length and contains an open reading frame (ORF) of 1 191 bp, encoding 396 amino acid residues. The putative protein is 45.01 kD with an isoelectric point (pI) of 6.35, and has no transmembrane region and signal peptide. The phylogenic tree indicated that HaJNK shares a high homology with JNKs from other insect species. Developmental stage-specific mRNA expression profiling showed that HaJNK had the highest expression levels in the egg stage. Tissue-specific mRNA expression profiling showed that HaJNK was specifically expressed in the compound eye, thorax and ovary of adult. The mRNA expression of HaJNK in female adults was induced by UV-A stress, increasing firstly and then decreasing with the increase of exposure time, and reached the highest expression level at 60 min post exposure to UV-A. Conclusion This study indicates that the expression level of HaJNK varies at different developmental stages, adult tissues and female adults of H. armigera exposed to UV-A for different time, suggesting that HaJNK may play an important role in the response to UV-A stress.
    Cloning and expression profiling of general odorant receptor gene GmolOR20 inthe oriental fruit moth, Grapholita molesta (Lepidoptera: Tortricidae)
    CHEN Li-Hui, LI Mei-Mei, CHEN Xiu-Lin, WU Jun-Xiang, XU Xiang-Li
    2019, 62(4):  418-427.  doi:10.16380/j.kcxb.2019.04.004
    Abstract ( 650 )   PDF (6085KB) ( 309 )     
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    Aim The objective of this study is to clone the gene of a general odorant receptor (OR) OR20 of the oriental fruit moth, Grapholita molesta, and to investigate its expression profiles in different developmental stages and adult tissues of the moth, so as to provide a theoretical basis for further functional study of the odorant receptor gene. Methods According to the antennal transcriptome of female adults of G. molesta, the open reading frame (ORF) of OR20 gene of G. molesta was cloned by PCR. The expression levels of this gene at different developmental stages (egg, 1-5 instar larva, pupa, and female and male adults), in different adult tissues (antenna, head with antenna removed, thorax, abdomen, leg and wing), and in antennae of adults of different age (1, 3, 5 and 7 day-old) were detected by qRT-PCR. Results The cDNA sequence of GmolOR20 gene (GenBank accession no.: MH898864) in G. molesta was obtained. Its complete ORF is 1 284 bp in length, encoding 427 amino acids with the predicted molecular weight of 49.83 kD, the isoelectric point of 8.57, and seven transmembrane domains. Multiple sequence alignment and phylogenetic tree analyses revealed that GmolOR20 is closely related with CpomOR15 of Cydia pomonella and CnigOR15 of Cydia nigricana, with the amino acid sequence identity of 87% and 84%, respectively. Developmental stage-specific expression results revealed that GmolOR20 was expressed in various developmental stages of G. molesta, and its expression levels in female and male adults were significantly higher than those in other developmental stages (P<0.05), but showed no significant difference between female and male adults. Tissue expression profiles revealed that GmolOR20 was highly expressed in the antenna of adults, with extremely significantly higher expression level in the antenna of female adult than in the antenna of male adult (P<0.01). GmolOR20 was also expressed in antennae of adults of different day-old, with significantly higher expression levels in antennae of the 1 and 3 day-old adults than in antennae of other day-old adults (P<0.05). Conclusion Based on the profiling results of GmolOR20, we infer that GmolOR20 may be involved in the recognition of plant volatiles and pheromones in G. molesta.

    Sequence analysis and gene expression profiling of odorant binding proteins in the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

    ZHANG Fang-Mei, LIU Yang, LI Xiang-Rui, ZHANG Yun-Hui, CHENG Deng-Fa, GUO Wen-Chao, TURSUN Ahmat
    2019, 62(4):  428-441.  doi:10.16380/j.kcxb.2019.04.005
    Abstract ( 697 )   PDF (5169KB) ( 353 )     
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    Aim Odorant-binding proteins (OBPs) play a fundamental role in insect olfaction. The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), is one of the most notorious insect pests of potato. The sequence properties and tissue expression profiles of 26 putative OBP genes of L. decemlineata were identified to clarify the molecular mechanisms of its olfactory perception. Methods Based on antennal transcriptome sequencing data of L. decemlineata, the phylogeny and tissue-specific gene expression profiles of 26 LdecOBPs (LdecOBP1-LdecOBP26) in L. decemlineata were analyzed by bioinformatic methods and qRT-PCR, respectively. Results Except LdecOBP26, the genes of the other 25 LdecOBPs have the full-length open reading frames, encoding 120-255 amino acid residues with the predicted molecular weights of 13.66-29.38 kD and isoelectric points of 4.12-8.42. The 25 LdecOBPs belong to two subfamilies, with 13 Classical-C OBPs and 12 Minus-C OBPs. Except LdecOBP3 and LdecOBP26, each of the other 24 LdecOBPs contains a signal peptide at the N-terminus consisting of 16-23 amino acid residues. These OBPs in each subfamily have their own typical conservative Cys residues. LdecOBPs are highly divergent and their amino acid sequence identities range from 3.20% to 41.91%. Phylogenetic analysis showed that LdecOBPs and GdauOBPs of Galeruca daurica are most closely related. Gene expression profiling showed the 26 LdecOBPs genes were expressed in different adult tissues of L. decemlineata, with 12 LdecOBPs genes (LdecOBP2, LdecOBP4, LdecOBP6, LdecOBP9, LdecOBP10, LdecOBP12, LdecOBP13, LdecOBP16, LdecOBP20-22 and LdecOBP24) highly expressed in antennae, two genes (LdecOBP5 and LdecOBP17) highly expressed in legs, and the other 12 (LdecOBP1, LdecOBP3, LdecOBP7, LdecOBP8, LdecOBP11, LdecOBP14, LdecOBP15, LdecOBP18, LdecOBP19, LdecOBP23, LdecOBP25 and LdecOBP26) expressed in tissues antennae, head (with antennae removed), thorax, abdomen, legs and wings. Conclusion These results establish a foundation for further research on the molecular mechanisms of chemical communications in L. decemlineata.
    Observation of fine structure of antennal sensilla in sexually dimorphic antennae of the blister beetle Epicauta impressicornis (Coleoptera: Meloidae) adults (In English)
    LIU Yang-Yang, LI Guo-Yong, YANG Lin, CHEN Xiang-Sheng
    2019, 62(4):  442-452.  doi:10.16380/j.kcxb.2019.04.006
    Abstract ( 637 )   PDF (21684KB) ( 312 )     
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    Aim The aim of this study is to observe the morphological characteristics of the main antennal sensilla of the blister beetle Epicauta impressicornis (Coleoptera, Meloidae) so as to provide a reference basis for further studying the biology and behavioral mechanisms of E. impressicornis, and a prerequisite for future electrophysiological studies of its antennal sensilla. Methods The morphology of the antennal sensilla of E. impressicornis adults was observed under scanning electron microscopy, and the quantity, distribution and the difference in antennal sensilla between the male and female were statistically and comparatively analyzed. Results The results revealed that the antennal sensilla of E. impressicornis adults show sexual dimorphism, and their type, abundance, and distribution have similarities and differences between both sexes. Seven types of sensilla, including sensilla chaetica type 1 (CH1), sensilla chaetica type 2 (CH2), sensilla basiconica type 1 (SB1), sensilla basiconica type 2 (SB2), Böhm sensilla (BB), sensilla auricillica (SA), and sensilla campaniformia (CA) were found on the antennae of both sexes. In addition, there are some unique sensilla including sensilla chaetica type 3 (CH3) and sensilla basiconica type 3 (SB3) on the male antennae, and sensilla basiconica type 4 (SB4), sensilla basiconica type 5 (SB5) and grooved pegs (GP) on the female antennae. Conclusion The types of antennal sensilla of E. impressicornis are rich and diverse. These antennal sensilla are speculated to function as pheromone receptors (CH1), chemoreceptors (CH2 and GP), olfactory receptors (CH3, SB1-SB5, SA and CA), mechanoreceptors (BB) and thermoreceptors (CA and GP) according to their morphology and distribution, as well as based on comparative analyses with the previously reported results.
    Biological activities of four components of essential oils against the wolfberry aphid (Aphis gossypii)
    CHEN Xin-Hua, WAN Wei, FENG Shu-Jun, XU Sheng-Li, YANG Jian-Jun, DUAN Li-Qing
    2019, 62(4):  453-460.  doi:10.16380/j.kcxb.2019.04.007
    Abstract ( 670 )   PDF (1480KB) ( 395 )     
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    Aim This study aims to evaluate the biological activities of four components of essential oils, namely eugenol, α-terpineol, cinnamon oil and citronella oil, to the wolfberry aphid (Aphis gossypii), and the effect of diethyl maleate and ethyl salicylate on the toxicity of these compounds to A. gossypii, so as to provide a scientific basis for more effective and green ways to prevent and control insect pests of the Chinese wolfberry, Lycium spp. Methods The repellent activity of the above four component compounds of essential oils to apterous adults of A. gossypii originated from Chinese wolfberry were tested by dichotomous choice method. The toxicity of these compounds to A. gossypii adults was evaluated by the method of residual film in glass tube. The in vitro activities of acetylcholinesterase (AChE) and adenosine triphosphatase (ATPase) of A. gossypii adults treated with these compounds were tested by bicochemical analysis. Results α-Terpineol (1%) showed remarkable repellency to apterous adults of A. gossypii, with the repellent rates of 58.1%, 58.6% and 55.7% at 1, 2 and 3 h after treatment, respectively. The repellent rate of the four compounds against A. gossypii adults at 3 h ranked in the descending order as α-terpineol>citronella oil>cinnamon oil>eugenol. Eugenol showed the highest toxicity to A. gossypii adults, with the LC50 value of 0.48 mL/L at 4 h post treatment, while the LC50 values of cinnamon oil, α-terpineol and citronella oil to A. gossypii adults were 1.23, 6.24 and 11.97 mL/L, respectively. The bioassay results against A. gossypii adults showed that the synergistic ratios of diethyl maleate to citronella oil, cinnamon oil, eugenol and α-terpineol were 2.75, 2.86, 1.78 and 1.56, respectively, while those of ethyl salicylate to citronella oil, cinnamon oil, eugenol and α-terpineol were 3.41, 2.67, 2.00 and 1.89, respectively. The toxicity ratios showed that the toxicities of the four compounds to A. gossypii adults had 49.9-fold difference. Eugenol mixed with diethyl maleate or ethyl salicylate showed the highest contact toxicity to A. gossypii adults. The four compounds tested had different effects on the activities of AChE and ATPase of A. gossypii adults. Eugenol had an inhibitory effect on AChE activity, but enhanced the ATPase activity at low concentrations and inhibited the ATPase activity at high concentrations. Conclusion α-Terpineol has high repellent activity against A. gossypii adults. The toxicities of eugenol, α-terpineol, cinnamon oil and citronella oil against A. gossypii adults differ much. Eugenol after mixed with diethyl maleate or ethyl salicylate shows enhanced toxicity to A. gossypii adults and may be a potential agent for controlling aphids. The tested four components of essential oils have certain inhibitory effects on the in vitro activities of AChE and ATPase of A. gossypii adults.

    Starvation tolerance and biological characteristics after starvation and refeeding of Hermetia illucens (Diptera: Stratiomyidae) larvae

    DENG Wen-Hui, WU Jia-Yuan, CHEN Tian-Yang, YIN Yu-Meng, ZHU Fen
    2019, 62(4):  461-467.  doi:10.16380/j.kcxb.2019.04.008
    Abstract ( 774 )   PDF (1377KB) ( 515 )     
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    Aim The aim of this study is to clarify the starvation tolerance of Hermetia illucens larvae and to examine the biological characteristics of development and fertility of starved larvae after refeeding, so as to provide a theoretical basis for assessing the effects of starvation on the subsequent development of H. illucens larvae and a guidance on production practices. Methods H. illucens larvae of different day-old or with different body weights were subjected to starvation for different periods of time. The relationships of starvation tolerance of the larvae with their day-old and body weight were established. Biological characteristics of 7 day-old larvae after being starved for different time and refeeding, including the time of prepupal appearance, cumulative prepupal rate, prepupal weight, and adult reproduction, were assayed. Results The median lethal time (LT50) of H. illucens larvae after starvation was exponentially related to their age in days and linearly related to their body weight. The 7-day-old larvae had relatively stronger starvation tolerance, with the LT50 value exceeding 50 d and the survival rate of 95% after 30 d starvation. As for the individuals with the body weight less than 0.5 g per hundred larvae, their LT50 value was less than 30 d. As for the individuals with body weights 2-2.5 g per hundred larvae, their LT50 value was 45-70 d. When the larvae over 8-day-old or heavier than 4.5 g per hundred individuals were subjected to starvation for 5 d, most of them entered the subsequent developmental stage ahead of time. During 0-40 d starvation, the prepupal rate had no obvious change, but the prepupal weight increased significantly. Short-term starvation (0-10 d) of larvae had no significant effect on the egg-laying amount of adults, but long-term starvation (30-40 d) of larvae had a significant effect on the egg-laying amount of adults. Moreover, the egg hatching rate decreased significantly when the larvae were subjected to starvation for more than 30 d. Conclusion The results suggest that H. illucens larvae of different day-old or with different body weights all show certain starvation tolerance, and the prepupal weight of starved larvae increases significantly after refeeding.
    Oviposition behavior of Sirex noctilio (Hymenoptera: Siricidae)
    XU Qiang, LV Hong-Wu, WU Cheng-Peng, MAO Yu, SONG Guang-Hui, SHI Juan
    2019, 62(4):  468-474.  doi:10.16380/j.kcxb.2019.04.009
    Abstract ( 994 )   PDF (12312KB) ( 222 )     
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    Aim To study the oviposition behavior of Sirex noctilio, and to determine its oviposition capability, so as to provide a data basis for evaluating its reproductive potential and damage. Methods Logs of host Pinus sylvestris var. mongolica damaged by S. noctilio were collected from Xindian State Forest Farm of Duerbote Mongol Autonomous County,Daqing,HeilongjiangProvince,Northeast China. The oviposition behavior process and pattern of S. noctilio under the laboratory conditions were observed and analyzed. The oviposition holes of S. noctilio on P. sylvestris var. mongolica were dissected, and their structure characteristics were observed. Results The results revealed that S. noctilio wasps were sexually mature upon emergence, and they could mate and/or lay egg immediately. The ovipositing process of female adults of S. noctilio was divided into four stages: drilling into the bark, drilling into the xylem, laying egg (including injection of poisonous mucus and symbiotic fungi Amylosereum areolatum), and withdrawing the ovipositor. The most frequent oviposition time was between 360 to 540 s, accounting for 41.40% of the total frequency of various oviposition time. During these four stages, the time of drilling into the xylem was the longest, taking at least 90% of the total duration of oviposition. S. noctilio female adult would carry out 1-4 drillings once it confirmed a position. The oviposition time (t) showed a significantly positive correlation with the number of oviposition cycles: 1 cycle when t<360 s; 2 cycles when 360 st<540 s; 3 cycles when 540 st<780 s; and 4 or more cycles when t780 s. The proportions of 1, 2, 3 and 4 cycles of oviposition at one oviposition hole were 21.66%, 41.40%, 27.39% and 9.55%, respectively. Conclusion The number of oviposition cycles of female adults of S. noctilio is positively correlated to its oviposition time. Based on this relationship, the number of oviposition cycles can be inferred once the oviposition time is investigated. The more the oviposition cycles of S. noctilio, the higher the risk of its harm to P. sylvestris var. mongolica.

    Genetic differentiation and phylogeography of the alpine butterfly Parnassius glacialis (Papilionidae: Parnassinae) inChina: evidence from mitogenomic AT-rich region

    WANG Yun-Liang, PAN Zhong-Qi, CHEN Ke-Ke, TAO Rui-Song, SU Cheng-Yong, HAO Jia-Sheng, YANG Qun
    2019, 62(4):  475-488.  doi:10.16380/j.kcxb.2019.04.010
    Abstract ( 856 )   PDF (2578KB) ( 386 )     
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    Aim This study aims to analyze the genetic diversity, genetic differentiation, and phylogenetic relationships of populations of the alpine butterfly Parnassius glacialis in China, to infer their origin and divergence time, and to explore their spatiotemporally evolutionary history. Methods The mtDNA AT-rich sequences of 325 individuals from 13 geographic populations of P. glacialis inChinaand 11 individuals of other 11 Parnassius species were amplified and sequenced, and their sequence variation and genetic differentiation were analyzed using MEGA 6.0, Dna SP 5.1, Arlequin 3.5 and other genetics analysis software. Using the closest relatives as the outgroups, the P. glacialis phylogenetic trees were reconstructed with such analytical software as PhyML3.0, MrBayes 3.2, and BEAST V1.8.3, and the origin and divergence time of the P. glacialis lineages were estimated by using relaxed molecular dating method and calibrations of the previous studies. Based on the present biogeographic distribution of P. glacialis and the main earth environmental events since the Quaternary Period, its dispersal route and spatio-temporal pattern and the underlying earth environmental factors were tentatively inferred. Results The AT-rich sequences of 325 P. glacialis individuals from 13 geographic populations ranged from 487 to 495 bp in length with the mean of 491 bp, being relatively conserved in length. The main length difference of the AT-rich region lies in the Poly-T or Ploy-A copy number, and the mean A+T content of the region is up to 95.76%. Totally 239 halotypes based on mtDNA AT-rich sequences were found in the 325 individuals of the 13 populations of P. glacialis, with its haplotype diversity (Hd) value of 0.9971, the nucleotide polymorphism index π of 0.02948, and the Theta (per site) Eta value of 0.06594. The reconstructed phylogenetic trees and molecular dating showed that P. glacialis is most closely related to P. stubbendorfii, and these two sister species began to differentiate at about 7.49 million years (Ma) ago in the late Miocene. The ancestors of P. glacialis were originated in the southwest of China (near the Hengduan Mountain-Himalaya Mountain of the Qinghai-Tibet northeastern edge nowadays) at about 1.53 Ma ago; then, they dispersed from their originating site into Xiaolongshan and Qinling Mountains; later, they diverged into two main lineages with some inter-mingled halotypes along the mountainous routes, accompanied by the Quaternary glacial-interglacial changes; lastly, the one lineage continuously spread northeastward to Funiu, Songshan, Taishan, Kunyushan Mountains, and the other lineage spread step-by-step to Dabie, Langyashan, Zijinshan and Tianmushan Mountains. Conclusion The results of our phylogenetic analysis of P. glacialis indicate that no pronounced correlations exist between genetic differentiation and geographical distance judged from higher genetic variance within populations than between populations. In addition, we propose that the divergence of the two main lineages of P. glacialis occurred in the mountainous areas with relatively higher latitude in the Middle Pleistocene and then spread to the mountainous areas with relatively lower latitude in South and East China due to the Quaternary glacial-interglacial cycles and different dispersal routes.
    Advances in insect immune priming
    ZHANG He, HUANG Shu-Ning, PU Yu-Chen, SHI Zhang-Hong, HOU You-Ming
    2019, 62(4):  489-505.  doi:10.16380/j.kcxb.2019.04.011
    Abstract ( 776 )   PDF (3121KB) ( 461 )     
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    Generally, insects lack acquired immunity and only rely on their innate immune defense system to deal with the infection of pathogenic microbes. However, an increasing number of studies show that early pathogenic infection experiences of invertebrates including insects can enhance the immunity to later pathogenic infection, and this phenomenon is called “immune priming”. Like the acquired immunity of vertebrates, some insects show a great degree of specificity and ability of memory after priming. This kind of improved protection can be species/strain-specific, and can be passed on to the next generation. Even though insects lack acquired immune molecular components, they can still achieve the memory and specificity of immunity, suggesting that there is a unique mechanism regulating this process in the innate immune system of insects. In this article we mainly illustrated the progress of studies on immune priming and trans-generational transmission, and discussed the specific conditions and influencing factors of insect immune priming as well. Furthermore, we also mentioned the potential regulatory mechanism of insect immune priming and trans-generational transmission. Besides, considering that the immune priming itself could be an energy-consuming process, we also argued the cost of immune priming from the aspect of priming plasticity. Finally, we brought forward the prospects of research directions of insect immune priming and its potential application in pest control in the future.

    Application of RNAi in insect pest management: important progress and problems 

    HU Shao-Ru, GUAN Ruo-Bing, LI Hai-Chao, MIAO Xue-Xia
    2019, 62(4):  506-515.  doi:10.16380/j.kcxb.2019.04.012
    Abstract ( 1332 )   PDF (1399KB) ( 906 )     
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    RNAi is regarded as a green pest control strategy most likely to be applied in insect pest control. In June 2017, United States Environmental Protection Agency (EPA) approved the first transgenic insect-resistant maize MON87411 expressing insect double-stranded RNA (dsRNA) in the world, and this brought a new upsurge of research of using RNAi technology in insect pest management. However, there are still some problems to be addressed in the application of RNAi technology in pest control, e.g., screening and application strategies of effective target genes, the sensitivity of lepidopteran insects to RNAi, the stability of dsRNA in environment, etc. In this article, we summarized the research and application of RNAi technology in relation to pest control over the past two decades. We also reviewed the feasibility, application methods, existing problems and some current solutions of RNAi technology. We found that the degradation of dsRNA in the midgut or hemolymph of some lepidopteran insects may be the primary reason of the low RNAi efficiency through a comprehensive analysis of recent research results. Through dsRNA modification or embedding by liposome or nanoparticle, it is possible to solve the problem of dsRNA degradation to a certain extent, thus improving the RNAi efficiency.
    Progress in pollination by dipteran insects
    WU Peng-Feng, ZHENG Guo
    2019, 62(4):  516-526.  doi:10.16380/j.kcxb.2019.04.013
    Abstract ( 810 )   PDF (1719KB) ( 394 )     
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    Pollination is a very important link in natural ecosystem, and it is also a key step related with the yield in agricultural ecosystem. As well known, hymenopterans are the most important pollinating insects. In fact, dipterans are also important pollinators due to the advantages of wide distribution, diverse richness, and enormous abundance. Yet the pollination by dipterans has not been paid enough attention. In this article we mainly summarized the main dipteran pollinators, the pollination effectiveness and pollination features of dipteran insects as pollinators, their coevolution with plants, and the ecological meaning of pollination by dipteran insects. It is recorded that at least 71 families of Diptera are involved in entomophily, and new evidence indicates that there are about 54 417 species of Diptera among flower-visiting insects, ranking the 4th in the orders of Insecta involved in entomophily based on the number of species involved. Although dipteran insects carry relatively less pollen on a single visit (compared to Hymenoptera), high visitation rate and enormous individuals ensure their position as effective pollinators. Pollination syndromes can effectively reveal the co-evolutionary relationship between plants and pollinators. Especially in recent years, the in-depth study of specialized pollination (e. g. Schisandraceae and midge system) and generalized pollination has deepened our understanding of coevolution. In terms of ecological meaning of pollination, on the one hand, dipteran insects are beneficial supplement to Hymenoptera, and on the other hand, in some special environments dipteran insects can play an irreplaceable role. At present the number of pollinating insects (including Diptera) has declined sharply, while the pollination value of dipteran insects is still less utilized. According to the current research situation in China, we put forward the following aspects as the future research focus: i) deepening case studies on the effectiveness and adaptability of dipteran insects as pollinators in order to determine the position of dipteran insects in pollination system; ii) strengthening the studies on habitat pattern change and insect diversity in order to clarify the impact of habitat change on insects; iii) sorting the relationship between flower-visiting and pollination, specialized pollination and generalized pollination in order to clarify the role of dipteran insects in the co-evolution with plants; and iv) gradually deepening the investigation of pollen waste and pollen competition in order to explore pollination strategies and plant reproductive strategies. All these efforts will be helpful for knowledge popularization, conservation and further utilization of Diptera as a pollinating group.

    Contents of Vol. 62 Issue 4
    2019, 62(4):  526-526. 
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