【Aim】 Reticulitermes flaviceps is one of the representative wood-feeding termite in our country, which has efficient cellulolitic system. This study aims to clone and characterize cellulase gene from R. flaviceps, so as to provide the theoretical basis for exploring cellulose resource of termites. 【Methods】 A β-glycosidase gene was cloned from R. flaviceps by using reverse transcription polymerase chain reaction ( RT-PCR), degenerate PCR and rapid amplification of cDNA end (RACE) methods, and its sequence was analyzed by bioinformatics tools. The corresponding protein was prokaryoticly expressed in Escherichia coli and the cellulase activity was measured after purification. 【Results】 The full-length cDNA sequence of β-glucosidase gene GZRfbg1 (GenBank accession no.: KU886065) was cloned from R. flaviceps, with a length of 1 691 bp and an open reading frame of 1 488 bp, encoding 448 amino acid residues with the typical structure of glycosyl hydrolase family (GHF) 1 domain. The calculated protein molecular weight is 56.45 kD. Multiple alignment analysis revealed that the deduced amino acid sequence of GZRfBG1 shares 95% identity with the salivary gland βglucosidase of Reticulitermes flavipes. GZRfBG1 was heterologously expressed in E. coli Rosetta 2 (DE3). The purified tagged GZRfBG1 exhibited increased specific activity to salicine, carboxymethyl cellulose sodium (CMC), and cellobiose. And the cellulolytic activity was also shown in a CMC containing agarose plate, in which clear digestion haloes were formed. 【Conclusion】 These results suggested that the salivary gland β-glucosidase from sibling species R. flaviceps and R. flavipes are very conservative in sequence and hydrolysis characteristics. This study of β-glucosidase gene can enrich the theoretical basis for the development of termite cellulases and phylogenetic study.

【Aim】 To clone the nuclear receptor gene from the cotton mirid bug, Apolygus lucorum, analyze its expression profiles, obtain the recombinant protein and prepare the highly specific monoclonal antibody against E75D protein. 【Methods】 The full-length cDNA of the nuclear receptor gene was cloned using RT-PCR and RACE techniques. The relative expression levels of this gene in female adults of different ages (1-16 day-old) and six tissues (fat body, flight muscles, ovary, Malpighian tubules, midgut and cuticle) in 7 day-old female adults of A. lucorum were determined using qRT-PCR method. The T vector containing the target gene was digested with the restriction enzyme NdeI/XbaI and subcloned, and the recombinant plasmid was specifically expressed after induction by IPTG. The recombinant protein was purified by GST agarose affinity chromatography and molecular sieve chromatography. The monoclonal antibody was obtained by mice immunity, cell fusion and ascites preparation, and its specificity was determined by Western blotting. 【Results】 A nuclear receptor gene was cloned from A. lucorum and named AlE75D (GenBank accession no.: KX912700). Its ORF is 1 911 bp in length, encoding a polypeptide with a predicted molecular mass of 75.68 kD. Amino acid sequence comparison indicated that AlE75D has the classic characteristics of the nuclear hormone receptor, including a highly conserved ligand-independent A/B activation domain (23 a.a.), a hinge region (D domain, 85 a.a.), a ligand-binding domain (LBD) (E domain, 190 a.a.) and F domain (338 a.a.), but has no C domain. AlE75D showed the highest similarity to E75 from the hemipteran insect Lygus hesperus (98% amino acid sequence identity). AlE75D was found to be continuously expressed throughout the whole adult stage of A. lucorum, and its expression level reached the peak in the 7 day-old female adult. The transcription levels of AlE75D were higher in the fat body and ovary; however, only small amounts of mRNAs were detected in flight muscles and Malpighian tubules. The vector containing AlE75D gene was digested and linked to the vector pCzn1. The recombinant plasmid pCzn1-AlE75D expressed the target recombinant protein of 75 kD after induction by IPTG. The recombinant protein was purified by using Ni-NTA agarose and used as the antigen, and one cell line which could stably passage and secrete monoclonal antibody against AlE75D protein was obtained. The monoclonal antibody could specifically bind to the total protein of A. lucorum as well as the recombinant AlE75D. 【Conclusion】 The expression of the nuclear receptor gene AlE75D in A. lucorum showed developmental stage- and tissue-specificity. The obtained monoclonal antibody against AlE75D recombinant protein is highly specific. The results could provide the basis for analyzing the gene’s function at the protein level.  

【Aim】 To clone a chitin synthase 1 gene from the oriental fruit moth, Grapholitha molesta (Busck) and to analyze its mRNA molecular characteristics and spatio-temporal expression patterns, so as to develop a basis for further research of the biological function of this gene. 【Methods】 The complete cDNA of a chitin synthase 1 gene was cloned from the 5th instar larvae and pupae of G. molesta by using degenerate primers and RACE technology, and two alternative splicing exons were obtained. Phylogenetic trees were constructed with the homologous sequences of other insects by using neighbor-joining method. The expression patterns of this gene in different tissues of 1 day-old prepupae (head, integument, fat body, midgut, trachea and Malpighian tubules) and different developmental stages (2nd-5th instar larva, prepupa, pupa and adult) were detected by RT-qPCR. 【Results】 The full-length cDNA of a chitin synthase 1 gene was cloned from G. molesta, and named GmCHS1. It encodes 1 565 amino acids, and contains 16 transmembrane helices. The two alternative splicing exons are located in the region consisting of 177 nucleotides that encodes 59 amino acid residues, and named GmCHS1a (GenBank accession no.: MF000781) and GmCHS1b (GenBank accession no.: MF000782), respectively. The phylogenetic trees showed that GmCHS1 belongs to the chitin synthase 1 family, and the two alternative exons of GmCHS1a and GmCHS1b are grouped into the corresponding two classes, CHS1a and CHS1b. The tissue expression profiles of GmCHS1 indicated that it had the highest expression level in the integument, followed by trachea and head, while had a low expression level or was hardly expressed in other tissues. The developmental expression profiles of GmCHS1 showed that it was expressed throughout the whole developmental stages, and showed high expression during larval-larval molting, prepupal-pupal and pupal-adult transformation. The expression levels of GmCHS1a were higher in the integument and head but slightly lower in trachea and fat body than those of GmCHS1b. During growth and development of G. molesta, GmCHS1a was mainly expressed during larval-larval molting and prepupal-pupal transformation, while GmCHS1b was expressed during the prepupal-pupal and pupal-adult transformation. 【Conclusion】 GmCHS1a and GmCHS1b should be classified into chitin synthase 1 family. The expression levels of GmCHS1a and GmCHS1b are significantly different in different tissues and developmental stages of G. molesta, suggesting that these two genes play different roles in the growth and development of G. molesta. This study lays the foundation for the further research of the function of GmCHS1a and GmCHS1b in G. molesta.  

【Aim】 In our previous studies, the activities of total esterases were found to be significantly increased in the chlorpyrifos, imidacloprid and deltamethrin resistant strains of the small brown planthopper, Laodelphax striatellus. The aim of this study is to identify the carboxylesterase gene causing this increase and to verify its roles in insecticide resistance. 【Methods】 The expression levels of carboxylesterase genes in female adults of the resistant and susceptible strains of L. striatellus were detected by transcriptome sequencing and RT-qPCR. Microinjection was used to establish a transgenic Drosophila melanogaster strain overexpressing the target gene. Topical application method was used to investigate the responses of transgenic D. melanogaster overexpressing the target gene to chlorpyrifos, imidacloprid and deltamethrin, respectively. 【Results】 The expression level of LsCarE1 (GenBank accession no.: HM600723) was upregulated in female adults of the chlorpyrifos, imidacloprid and deltamethrin resistant strains of L. striatellus. Based on the sequence of LsCarE1, codon optimization was performed, and the open reading frame of LsCarE1 was cloned into the transgenic vector pUAST-attB. The transgenic homozygous strain UAS-LsCarE1^Optimized was successfully established and then genetically crossed with the GAL4 driver line to obtain a da>LsCarE1^Optimized strain that exhibited the overexpression of LsCarE1. The expression level of LsCarE1 in the da>LsCarE1^Optimized strain was 257.3 times as high as that in the reference strain UAS-LsCarE1^Optimized. The expression of LsCarE1 was not detected in the reference strain da>gal4. Furthermore, the expression levels of the endogenous esterase homologous genes in D. melanogaster were significantly lower than that of LsCarE1. The bioassay results indicated that as compared with the control strain da>gal4, the overexpression strain da>LsCarE1^Optimized  showed increased tolerance to chlorpyrifos and imidacloprid by 4.19- and 2.46-fold, respectively, but showed no significantly increased tolerance to deltamethrin. 【Conclusion】 The overexpression of LsCarE1 is related to the increased resistance to chlorpyrifos and imidacloprid in L. striatellus.  

【Aim】 This study aims to clarify the electroantennographic and olfactory responses of female wasps of the eulophid Aprostocetus prolixus to volatiles of Morus alba branches induced by jasmonic acid (JA), so as to reveal the chemical mechanisms of indirect resistance in M. alba branches against Apriona germari. 【Methods】 The volatiles from M. alba branches treated with JA were collected by using the dynamic headspace volatile collection method. The electroantennographically active compounds for female wasps of A. prolixus were screened and indentified by coupled gas chromatography-electroantennographic detector (GC-EAD) and GC/MS, respectively, and the differences in emission rates of the EAD-active components between the JAtreated M. alba branches and the water-treated control branches were also compared. Furthermore, the volatile compounds attractive to female A. prolixus were determined by Y-tube olfactometer. 【Results】 The results demonstrated that Z-3-hexenol, β-terpinene, β-phallandrene, perillene, methyl salicylate and other three unknown chemicals from M. alba branches treated with JA elicited significant GC-EAD responses in female wasps of A. prolixus. The emission rates of β-phallandrene, perillene and methyl salicylate from the JA-treated M. alba branches were significantly higher than those from the control branches. Furthermore, β-phallandrene and perillene were detected only in the volatiles of the JA-treated plants. However, there was no significant difference in the emission rate of Z-3-hexenol between the JA-treated plants and the control plants. And 0.1% β-phallandrene, 0.1% perillene and 0.01% and 0.001% methyl salicylate were significantly attractive to female wasps of A. prolixus. 【Conclusion】 The results suggest that highly elevated emission of β-phallandrene, perillene and methyl salicylate from the JA-treated M. alba branches is one of the important mechanisms of the JA-induced indirect resistance in M. alba tree against A. germari.    

【Aim】 Heavy metal pollution has become one of important environmental issues globally. This study aims to evaluate the effects of cadmium exposure on the flight performance of the beet armyworm, Spodoptera exigua, a migratory insect. 【Methods】 Insect flight information system was used to study the flight performance of female and male adults of S. exigua at different ages (1, 3, 5 and 7 day-old), which were fed with the artificial diets containing different concentrations of cadmium (0, 0.20, 0.80, 3.20 and 12.80 mg/kg), respectively. 【Results】 There were significant differences in the flight performance of S. exigua adults exposed to different concentrations of cadmium. The 3 day-old female adults stressed by low concentration of cadmium (0.20 mg/kg) were the best fliers with the longest average flight distance (36.96 km). The flight performance of S. exigua adults exposed to 0.20 mg/kg cadmium was not significantly different from that of the control. With the increase of cadmium concentration, the flight performance of both male and female adults decreased significantly. The negative effects of heavy metal cadmium stress on the performance of male adults were more obvious than on that of female adults. 【Conclusion】 Different concentrations of cadmium stress have significant effects on the flight performance of S. exigua adults of different ages and different sexes.  

【Aim】 In the present study, we assessed the functional response of the 4th instar larvae of a coccinellid species, Menochilus sexmaculatus (Fabricius) on aphid species, Aphis craccivora Koch and Lipaphis erysimi (Kaltenbach) under prey fluctuating conditions. L. erysimi is a defended prey that contains allyl isothiocyanates. We hypothesized that under experimental prey conditions, larvae reared on optimal/abundant prey would show better functional response than scarce prey reared larvae. But the slope of the functional response curves would be lower on L. erysimi than on A. craccivora. 【Methods】 The 4th instar larvae of M. sexmaculatus were abruptly shifted from their rearing conditions (viz. scarce/optimal/abundant prey) to different experimental conditions (i.e., extremely scarce/scarce/sub-optimal/optimal/abundant prey) and their functional response curves were extrapolated. 【Results】 The results revealed that despite prey resource fluctuations, the 4th instar larvae of M. sexmaculatus exhibited the type-II response on A. craccivora, but a modified type-II response on L. erysimi. Further, irrespective of prey species, the 4th instar larvae that were reared on optimal/abundant prey exhibited normal predation rates under five experimental conditions. But, the 4th instar larvae reared on scarce prey compensated for a shortage of food by consuming higher prey biomass than usual when suddenly switched over to the optimal/abundant prey experimental conditions. However, they exhibited the highest prey consumption on abundant prey and the lowest on extremely scarce prey experimental conditions. Moreover, higher attack rate but lower prey handling time on A. craccivora were recorded. 【Conclusion】Our results suggest that fluctuations in the availability of L. erysimi may modify the functional response curves of M. sexmaculatus larvae. However, A. craccivora is more suitable as a prey for M. sexmaculatus than L. erysimi.    

 【Aim】 Sclerodermus parasitoids cooperate among foundresses (mated female wasps) in parental care, being an unique group performing quasi-social behavior in parasitoids. By cooperation foundresses can effectively exploit large sized hosts with stronger defenses, yet it is unclear if kinship among foundresses plays a role in this cooperation. This study aims to examine the effects of foundress-offspring kinship on maternal care behavior and offspring developmental performance in S. guani attacking the pupae of the host Tenebrio militor. 【Methods】 Maternal care provided by either a birth or adoptive foundress was evaluated by observing larva-translocation behavior using video camera and examining the developmental performance including larval survival, pupation, sex ratio, and body weight. 【Results】 The larva-recognition time by birth foundresses (32.73 s) was not significantly different from that by adoptive foundresses (19.64 s), but the number of larvae examined by birth foundresses with antenna-tapping (176 during 12 h) was twice as many as that by adoptive ones. The time for a bout of translocation did not differ between birth (27.31 s) and adoptive (41.55 s) foundresses. The interval in time between two bouts of translocation differed between two types of foundresses, of which birth foundresses had a shorter interval (60% of that by adoptive ones). The survival rate of offspring larvae tended by a birth foundress (90%) was not different from that by an adoptive foundress, yet the adult emergence rate from pupae was slightly higher for birth foundresses (95.5%) than that for adoptive foundresses (91.4%). The offspring sex ratio was female biased (90%) and did not differ between birth and adoptive foundresses. The body weight of adult female offspring was not significantly different between two kinds of foundresses. 【Conclusion】 The results of this study suggest that foundress-offspring kinship has a discernible effect on larvatranslocation behavior, but a negligible effect on offspring development.  

【Aim】 To clarify the migration patterns of subterranean pest insects in the soil in different seasons, so as to provide a theoretical basis for integrated pest management. 【Methods】 The five-point sampling method was used for the field surveys in winter wheat-summer corn rotation fields in Linfen, Shanxi province, and the relationships between the distribution of underground pest insects and soil temperature, humidity and environment were analyzed. 【Results】 The survey results showed that the underground pest insects migrated upward from mid-March to early April, and downward from early October to early November. Different underground pest insects showed different migration time, distribution depth and movement range. With rising temperature in spring, the upward migration order of underground pest insects was wireworms, white grubs, mole crickets, while the downward migration order was reverse as temperature decreased in winter. In addition, soil insects could dig more than 20 cm below ground at low temperature in winter, while at high temperature in summer the depth was about 10 to 20 cm below ground. And for the same species of underground pest insects, they could dig the soil deeper during overwintering period than during oversummering. Furthermore, in view of the range of vertical movement of different varieties of soil insects in the whole year, white grubs moved in shallow soil layer, while mole crickets moved in deeper soil layer and had the deepest digging depth. 【Conclusion】 The migration patterns of various underground pest insects are different, and the migration phenomenon that pest insects move up and down is repeated yearly.  

【Aim】 Carabid beetles are one of the most abundant groups which inhabit soil surface, and they are more sensitive to the change of habitats. The objective of this study is to reveal the mechanisms of formation and stabilization of carabid species biodiversity by analyzing the effects of topographic factors on the distribution pattern of carabid species diversity in the Helan Mountains, northwestern China. 【Methods】 The community structure and species diversity of carabid beetles were investigated from July to August 2015 using pitfall traps in the Helan Mountains. Carabid beetles were caught from 98 sampling plots of five vegetation habitats along the elevation gradient, i.e., mountain needle-leaf forest, mountain broadleaf forest mountain shrub, mountain grassland and piedmont desert grassland. Based on a survey of the 98 sampling plots in the study area, canonical correspondence analysis (CCA) was performed to analyze the relationships between diversity indices and topographic factors, and generalized additive model (GAM) was employed to model the response curves of diversity indices to elevation. 【Results】 A total of 10 989 carabid beetles belonging to 65 species and 21 genera were collected. Of these beetles, Pterostichus gebleri and Harpalus salinus were the dominant species in the area, accounting for 44.93% and 11.33% of the total number of individuals, respectively. Among the habitats, the carabid beetle community in mountain broadleaf forest had the highest species richness while that in mountain needleleaf forest had the highest Shannon-Wiener diversity index. The evenness in piedmont desert grassland was the highest, while its diversity and species richness were the lowest. It was observed that elevation, slope aspect, slope grade, topographic wetness index and profile curvature had significantly integrative effects on the distribution patterns of carabid species diversity. Elevation had significant effects on the distribution patterns of total carabid communities in all the five vegetation habitats, and slope aspect only affected the distribution patterns of mountain needle-leaf forest and piedmont desert grassland significantly. Species richness and the number of individuals had a unimodal pattern with elevation, Shannon-Wiener diversity index increased at first and then remained stable, while the evenness index had a V-shape trend. 【Conclusion】 The distribution patterns of carabid beetles in the Helan Mountains are formed by the synthetic action of a variety of topographic factors, among which elevation plays an important role.

 【Aim】 To study the morphology and nesting behavior of Xylocopa rufipes Smith, so as to provide a theoretical basis for the conservation and management of carpenter bees. 【Methods】 A sweep net was used to collect X. rufipes adults. The nesting sites and nest substrates of X. rufipes were observed through visual observation and photographing in different regions, and the morphological indexes and the structure and composition of nests of X. rufipes were measured with vernier caliper. The number of foundresses within nests was determined by counting the number of foundresses contained within destructively sampled nests and by observation of female adults as they entered or exited nest entrances. 【Results】 Male and female adults of X. rufipes exhibited some important differences in body shape. Two spines on the outer apex of the hindtibia of female adults distinguished females of subgenus Bomboixylocopa, to which X. rufipes belongs, from all other Xylocopa species. Under natural conditions, X. rufipes chose nesting sites in wood girder trusses on old houses and temporary wood sheds, or firewood piles. Nesting substrates of X. rufipes were mainly dry woods of spruce, paulownia and cotton wood. Nest structure of X. rufipes was mainly divided into two types, i.e., the branched and unbranched, which were accounting for 73.91% and 26.09%, respectively. The entrance hole of nests penetrates the wood inclined to the grain (acute angle). It was nearly round. There were 1-10 tunnels per nest, with 1-8 cells (3.63±2.08 on average) per branch tunnel. The cell length was 15.37±0.22 mm (10.66-21.98 mm on average), the cell diameter was 12.33±1.08 mm (9.79-14.40 mm on average), and the thickness of cell partition was 5.09±0.13 mm (1.87-8.31 mm on average). Destructively sampled nests contained 0-6 live female adults with a mean of 2.08±1.61 live foundresses per nest (n=13 nests). Based on the observed female adults entering and exiting nests in the field in 2014, 2015, and 2016, the average number of females per nest was 2.48±1.24 (n=23 nests). 【Conclusion】 X. rufipes is socially polymorphic with both solitary and social nests in the same population.  

【Aim】 This study aims to explore the genetic diversity, genetic differentiation and phylogenesis of Tetranychus truncatus populations in Gansu province, northwestern China. 【Methods】 The mtDNA COI gene in 518 individual samples of T.truncatus, which were collected from 34 populations in 8 different habitats of Gansu province from June to September in 2016, was amplified, sequenced and analyzed. And its sequence variation and genetic differentiation were analyzed using MEGA 7.0, Dna SP 5.0 and other software. 【Results】 The sequenced fragment is 402 bp in length. The average contents of A, T, C and G are 32.2%, 43.2%, 10.5%, 14.0%, respectively. The A+T content (75.4%) was apparently higher than the G+C content (24.6%), with an obvious A/T bias, and the nucleic acid diversity was 0.0328. There were 12 haplotypes in 34 populations, and the haploid type index was 08004. In 12 haplotypes, H2 occurred in the highest number of individuals, which was distributed in 5 ecoregions, appeared 14 times, and occupied 41% in the number of individuals. Five cluster groups were clustered together in the haplotype mediation network diagram. NJ phylogenetic tree showed that 12 haplotypes were divided into four branches, and this result was the same as that of the mediation network diagram. Genetic distance of all the populations was among 0.001-0.08955. UPGMA dendrogram showed that JQ (Jiuquan) population and HS (Heshui) population had higber genetic differentiation with other populations. Mantel test result showed no significant correlation between genetic distance and geographical distance (r=0.043, P>0.05). The genetic differentiation index (Fst) among 34 populations was 0.11995, and the variation proportion among populations was 1.20%. 【Conclusion】 There is no significant correlation between genetic distance and geographical distance among 34 populations of T. truncatus in eight ecoregions of Gansu province. The genetic variation of T. truncatus is mainly within populations, and there is no obvious genetic differentiation among populations.  

Cruciferous plants (Cruciferae) possess a strong glucosinolate-myrosinase defense system, known as the “mustard oil bomb”, which has been well characterized as a plant chemical defense mechanism. Glucosinolates and myrosinases are separately stored in different compartments in host plant cells. However, insect herbivore feeding, pathogen attacks and mechanical injuries may trigger interactions between these compounds， whereby myrosinase hydrolyzes glucosinolates to generate toxic products, such as isothiocyanate, nitriles and other organic thiocyanates. Insect herbivores, in turn, have evolved ingenious detoxification strategies to overcome plant chemical defenses. Corresponding to different glucosinolate profiles, these strategies are also diverse, not only between the groups of generalist and specialist herbivores, but also within each of the groups. Based on the previous studies, the major types of glucosinolates, the glucosinolate-myrosinase defense system, and the insect herbivory-induced defense responses of cruciferous plants were reviewed in this article. And how cruciferous insect herbivores detoxify, sequestrate, transport and utilize glucosinolates of their host plants were elaborated with a view to provide insights into the evolutionary adaptation of cruciferous plants and insect herbivores.