A major challenge in pest management is insecticide resistance. To effectively prevent and manage resistance, it is essential to understand the biochemical and physiological changes induced by insecticides. Some molecular mechanisms that are responsible for insecticide resistance were well known whereas others are to be discovered. So the comparative proteomic approach was employed to investigate the proteomic differences between the deltamethrin-sensitive strain (DS) and the deltamethrin-resistant strain (DR) of the diamondback moth (Plutella xylostella L.). In this study, about 300 differentially expressed protein spots were detected on each SDS-PAGE gel, among which 23 proteins had a 2.5-fold expression difference between the two strains. Eight proteins were successfully identified by MALDI-TOF-MS, including chemosensory protein CSP2, Cu/Zn superoxide dismutase (SOD1), peroxiredoxinlike protein, etc. Expression of the five proteins at the mRNA level was analyzed by real-time quantitative PCR, and the results showed that the mRNA expression level did not fully reflect the protein expression level. Western blotting validated the proteomic result of SOD1. This study provides strong evidence that deltamethrin can induce the proteomic change in adult diamondback moth, and is helpful to understanding the resistance development and selecting the action targets of deltamethrin.

To explore the signal transduction pathway of important factors in olfactory formation in Apis cerana cerana, the cDNA sequence encoding a sensory neuron membrane protein (SNMP) (GenBank accession no. KC012595), named as AccSNMP1, was cloned by RT-PCR from the Chinese honey bee, Apis cerana cerana. Sequence analysis results showed that the open reading frame (ORF) is 1 563 bp in length, encoding 520 amino acids with the predicted molecular weight of 58.02 kD and the theoretical isoelectric point of 5.83. Multiple sequence alignment indicated that AccSNMP1 from A. cerana cerana shares different identities with those from other nine insects at the amino acid level. The AccSNMP1 gene from A. cerana cerana has high amino acid sequence identity with that of Apis mellifera (99.2%) and Bombus impatiens (90.9%), while has the lowest amino acid sequence identity with that of Tribolium castaneum (22.7%). The phylogenetic analysis indicated that A. cerana cerana species has a close relationship with A. mellifera and Bombus impatiens. Tissue expression profiling of AccSNMP1 quantified by real time RT-PCR demonstrated that it was highly expressed in antennae and legs of A. cerana cerana, showing a significant difference with that in thorax, abdomen, proboscis and head without antennae and proboscis (P<0.05). A recombined plasmid pEASY-E1-AccSNMP1, containing the coding sequence of AccSNMP1, was constructed using pEASY-E1 as the fused expression vector, and AccSNMP1 was expressed successfully after induced with IPTG in BL21 (DE3) strain of Escherichia coli. The results provide the basis for further studying the functions of sensory neuron membrane protein gene in A. cerana cerana to better understand its action mechanisms.

 The spiralling whitefly (SWF), Aleurodicus dispersus Russell, is an important agricultural and forest pest. In this study, we detected and analyzed the infection status and the gene sequences of three secondary endosymbionts Cardinium, Arsenophonus and Wolbachia in the SWF populations of 16 districts in Hainan province, southern China, based on 16S rDNA of Cardinium and Arsenophonus and wsp gene of Wolbachia. The results showed that the spiraling whitefly was infected by both Cardinium and Arsenophonus. The infection rate of Arsenophonus was 100% in A. dispersus populations from Ledong, Lingshui and Chengmai, and 66.7% in the populations from Sanya, Qiongzhong and Lingao, while there is no infection of Arsenophonus in the populations from Danzhou, Wuzhishan and Wanning. Similarly, the infection rate of Cardinium was 100% in A. dispersus populations on host plants Pterocarpus indicus in Qionghai and Baisha and Psidium guajava in Sanya, and less than 66.7% in the populations on other host plants. Among the 43 populations of A. dispersus detected, 40 and 31 populations were infected with Arsenophonus and Cardinium, with the infection rates of populations of 93.0% and 72.1%, respectively. Among the tested 120 individuals for detecting Arsenophonus infection and 93 individuals for detecting Cardinium infection, the numbers of infected individuals by Arsenophonus and Cardinium are 105 and 70, with the infection rate of individuals of 87.5% and 75.3%, respectively. The infection rate of populations and the infection rate of individuals by Wolbachia were 2.3% and 0.8%, respectively. The Cardinium 16S rDNA gene of different populations of A. dispersus in Hainan shares the same sequence, and has a high identity (97.6%) with the Cardinium 16S rDNA gene of Bemisia tabaci. The Arsenophonus 16S rDNA gene of different populations of A. dispersus in Hainan also shares the same sequence, with 85.1% identity with the Arsenophonus 16S rDNA gene in A. dispersus population in Canary Islands. In addition, Wolbachia in A. dispersus belongs to B group according to the analysis of wsp genes, and this is the first record in China.

To understand the effects of insecticides on the adaption of the whitefly Bemisia tabaci Mediterranean to stress environment, the expression of the heat shock protein gene hsp70 in this whitefly was investigated using real-time quantitative PCR after treatment with LC₂₅, LC₅₀ and LC₇₅ of nitenpyram, chlorpyrifos and beta-cypermethrin, respectively, at different temperatures. The results showed that at the lower temperature (15℃) the treatments of the three insecticides at LC₅₀ and LC₇₅ for 24 h significantly induced an increase in the expression level of hsp70, and then the expression was decreased gradually and showed no difference from the untreated control at 72 h after treatment; the three insecticides at LC₂₅, however, showed no effect on the expression of hsp70. At room temperature (25℃), nitenpyram, chlorpyrifos and beta-cypermethrin at LC₅₀ and LC₇₅ induced the expression of hsp70 significantly at 24 h after treatment, and then the expression levels were decreased gradually to the normal level at 72 h after treatment; the three insecticides at LC₂₅, however, induced an increased expression of hsp70 with the treatment time. At a higher temperature (32℃), nitenpyram, chlorpyrifos and cypermethrin at LC₂₅ and LC₅₀ significantly induced the expression of hsp70 at 24 h after treatment and the expression levels were then decreased and showed no difference from the control at 72 h after treatment. The high-level expression of hsp70 induced by insecticides enhances the tolerance of the whitefly to insecticides and high temperature, which may be one of the reasons that this whitefly expanded quickly in China.

In order to clarify whether DNA methylation takes part in insecticide resistance, the 3rd instar nymphs of the brown planthopper, Nilaparvata lugens, in 9 generations were sprayed by imidacloprid continuously in the laboratory, and AFLP technique was used to test the variation in DNA methylation polymorphism of the brown planthopper during the continuous application of imidacloprid. Using 25 pairs of AFLP primers, we obtained 120 loci, of which 15 loci displayed polymorphism within samples and a total of 78 polymorphic bands were obtained for these loci. The highest and lowest rates of polymorphic bands, 10.26% and 1.28%, occurred at the 5th and 6th generation, respectively. The change trend of polymorphism indicated that in the early screening stage (the earliest three generations), the brown planthopper had quick responses to imidacloprid with the rates of polymorphic bands of 3.85%-6.41%; in the middle screening stage (from the 4th to 6th generation), its responses fluctuated substantially with the rates of polymorphic bands of 1.28%-10.26%; and in the late screening stage (from the 7th to 9th generation), its responses varied very little with the rates of polymorphic bands of 5.13%-7.69%. These results suggest that imidacloprid can induce DNA methylation in the brown planthopper, therefore onset of resistance to insecticides, and DNA methylation may take part in the genome defense of planthoppers to imidacloprid selection.

 In order to study the insecticidal activity and toxicity mechanism of α-terpineol, a plant volatile organic compound, we tested the acute toxicity of α-terpineol against the 4th instar larvae of Zophobas morio in a gas-fumigation system and investigated the in vivo activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in the treated larvae at different fumigation duration. The results showed that the LC₅₀ and LC₂₀ values of α-terpineol against the 4th instar larvae in acute toxicity test at 48 h after fumigation were 69.425 μg/L and 59.916 μg/L, respectively. Under the fumigation of α-terpineol at two concentrations (LC₅₀  and LC₂₀ ), the activities of SOD, POD and CAT showed a time-course change, first increasing and then decreasing. It is so inferred that the gradual accumulation of α-terpineol in the treated larvae produces significantly negative effects on the activities of SOD, POD and CAT in their bodies, and this may lead to a decline in scavenging activity of free radicals and stronger toxic effects on Z. morio larvae.

This study aims to detect imidacloprid residue in wheat seeds harvested form seeds treated with different dosages of imidacloprid and its impact on the development and reproduction of the grain aphid, Sitobion avenae (Fabricius). Wheat seeds were coated with imidacloprid (60% FS) in a proportion of 2, 4, 6, and 8 g/kg, respectively, and imidacloprid residue in harvested wheat seeds was detected by UPLC-MS/MS. Life table of S. avenae laboratory populations was constructed to compare various parameters of this insect feeding on wheat plants grown from the harvested seeds. The results showed that imidacloprid residue was positively correlated with the treatment dosage, and the residue in wheat seeds harvested form seeds treated with 8 g/kg imidacloprid reached the highest level (0.0290 mg/kg). Life table metrics showed that the larval and imaginal periods were shortened, and the proportion of alates and aphid fecundity were increased in the treatments, but no significant difference existed in these parameters between the treatments and the control (P=0.392＞0.05). Net reproduction rate, the intrinsic rate of increase and the finite rate of increase in the treatments were, respectively, higher than those of the control. In addition, the population doubling time and the mean generation time in the treatments were reduced compared to the control. But there were no significant differences in all of the parameters between the treatments and the control (P=0.406). The results suggest that trace residue of imidacloprid in wheat seeds has no significant impact on the development of S. avenae, but affects the reproductive capacity of aphids in certain degree.

To explore how leaves of Ficus benjamina Linn. are damaged by rasping-sucking feeding of thrips, we studied the microstructure and the contents of amino acids and proteins in these leaves by scanning electron microscope and automatic amino acid analyzer. The results showed that after F. benjamina leaves were rasped and sucked by thrips, the microstructure of leaf surface had obvious changes, including: the wax layers cracked, the epidermal cells were injured, the function of stoma was lost and the functions and omamental value of the plant were also influenced. The foliar injuries by thrips obviously influenced the protein contents (P<0.01) in injured leaves, showing difference among different damage grades of injured leaves. Protein concentration in leaves with the 1st damage grade decreased fastest and was lower than those in leaves with other damage grades, while those in leaves with the 2nd and 3rd damage grades decreased slowly, and that in the leaves with the 4th damage grade was higher than those in undamaged leaves. There were 9 essential amino acids (EAAs) which are necessary for the development of thrips and 8 non-essential amino acids (NEAAs) in F. benjamina. In the leaves with the same damage grade, individual amino acid concentration was different for 17 amino acids and could be divided into three grades, but was relatively stable; while in the leaves with different damage grades, the concentrations of amino acids were closely related to the damage degree. The damages of leaves by thrips also resulted in the decrease of concentrations of total amino acids (TAA), EAAs and NEAAs in leaves with different damage grades, especially in the leaves with the 2nd and 3rd damage grades, but caused certain increase to the contents of three essential amino acids (arginine, methionine and lysine) and four non-essential amino acids (aspartic acid, cystine, serine and tyrosine). This research provides basic information on the changes of surface ultrastructure and the nutritional and physiological indexes of the host plant leaves damaged by thrips at the micro level. It also quantifies the functional benefit and loss of F. benjamina leaves caused by thrips.

The ber fruit fly, Carpomya vesuviana Costa, is currently listed as a quarantine pest which is prohibited into China, and its occurrence has led to disastrous damage to Ziziphus, especially its larvae feed sarcocarp, affecting the quality and commodity price of jujube products. The biological characteristics of the ber fruit fly, including eclosion, mating, oviposition and the effective accumulated temperature, were studied through field survey and laboratory observation in Xinjiang. The results showed that the process of eclosion can be divided into four stages: cracking and crawling out pupal shell, crawling around, wing stretching and flying. About 86.3% eclosion of the ber fruit fly mainly occurred from 8:00 to 11:00, and the peak time was around 10:00. The mating process lasted about 309.00±8.46 min, with the peak time occurring at 11:00-12:00 and 20:00-21:00. Oviposition consists of four stages, i.e., orientation, puncture, ovulation and ending, with the average time about 8.20±0.51 min. Fewer eggs were laid before 9:00 and after 21:00. The highest number of eggs laid per female per day was 16, the average number of eggs laid per female per day was 6-9, and 1-6 eggs were laid in each oviposition aperture. The developmental threshold temperature and effective accumulated temperature were different during each stage (egg, 13.75℃and 48.18 day-degrees; pupa, 6.38℃and 357.17 day-degrees; from egg to pupa, 8.78℃ and 283.29 day-degrees; larva, 6.39℃ and 245.61 day-degrees, respectively). This study provides basic data for further studying and sustainable control of this serious pest.

Oedaleus asiaticus Bei-Bienko is one of the major pest insects in the grasslands and agro-pastoral ecotone in North China. By using 8 microsatellite primer pairs, the genetic diversities of 15 geographic populations of O. asiaticus in Inner Mongolia, northern China were analyzed in order to evaluate the genetic variability within populations and genetic differentiation among populations of O. asiaticus at the molecular level. The results showed that the effective number of alleles was 3.4517-13.2881, the polymorphic information content was 0.5601-0.8563 and the Shannon’s diversity index was 0.7018-4.1789. The mean expected heterozygosity of the 15 populations was 0.6836, with the Nei’s expected heterozygosity of 0.5303-0.6513 and genetic distance of 0.1092-0.4235. The mean fixation index (Fst) and the mean gene flow (Nm) were 0.1612 and 1.6164, respectively. The 8 microsatellite loci selected are of high polymorphism, this grasshopper keeps a high genetic differentiation and moderate gene flow among populations, and the genetic variability among individuals within a population is higher than that among populations. O. asiaticus populations from 15 areas were classified into 6 groups according to the genetic distance. Genetic differentiation between populations shows a positive correlation with geographical distance. High mountains and deserts always block the population migration between areas, which is possibly the main cause of genetic differentiation. The study investigates the intrinsic connection among populations from different areas at the molecular level and provides some basic information on molecular biology for developing integrated management strategies against O. asiaticus.

 Mosquitoes are highly dependent on their olfactory system for chemical communication with the external environment including searching for foods, mating partners and oviposition sites. This article reviews the research progress on neuron projection mechanism of olfactory system to odor signals in mosquitoes. Olfactory appendages in moquitoes include antennae and maxillary palps that carry a variety of sensilla. Sensilla trichodea and sensilla grooved-peg in the antennae are sensitive to ammonia, L-lactic acid and carboxylic acids. The grooved peg sensilla in the maxillary palp are sensitive to carbon dioxide. These sensilla house olfactory receptor neurons (ORNs) in which olfactory receptor proteins are embedded. Host detection in mosquitoes starts with interactions between odorants and receptor proteins present on the dendritic membrane of the ORNs. ORNs are divided into different functional classes based on the response spectra to different odours. ORNs project to different glomerular areas of the antennal lobe (AL) in the deuterocerebrum of the central nervous system. The antennal lobe glomeruli in different response area are identified. The neuron signal is finally transduced to projection neuron (PN) in the potocerebrum and elicits the behaviour response of mosquitoes. These researches shed light on the neuron transduction channel of odor signal in olfactory system in mosquitoes. These results are very important for us to understand not only olfactory system in mosquitoes but also the odor perception mechanism of other insect species and human, and are helpful for further exploration in neuron science.

The whitefly Bemisia tabaci is considered taxonomically as a species complex which contains some destructive pests worldwide. Two of the most prevalent cryptic species are B. tabaci Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED). They are invasive cryptic species and often occur in some areas in China. The MED particularly has strong resistance to some insecticides and is more difficult to be controlled.  In this study TaqMan allele-selective PCR was used for high-throughput allelic discrimination of MEAM1 and MED. A single nucleotide polymorphism (SNP) in a conservative region of the mitochondrial cytochrome oxidase I (mtDNA COI) gene was selected as the amplification target. The TaqMan-MGB fluorescent dye-labeled was used in real-time quantitative PCR. Fourteen populations of B. tabaci collected from Beijing were identified with the method. The results showed that all samples of B. tabaci clustered with the known MED species as shown by the higher fluorescence of FAM dye in scatter plot analysis of fluorescence data, suggesting that all Beijing populations examined are MED. The results prove that the method has the advantage of SNP genotyping, with which MEAM1 and MED can be identified rapidly, reliably and high-throughput, and this provides a new alternative way for identification of cryptic species and important information for management strategy selection.

Tetraphleps galchanoides Ghauri is an important natural enemy to the hemlock woolly adelgid (HWA), Adelges tsugae (Annand). An artificial pudding diet (APD) mainly consisting of protein, fat and carbohydrates was prepared with the production rate of 74.5%, the moisture content of 8.6%, and the score of sensory evaluation of 81.7. To evaluate the efficiency of APD for rearing T. galchanoides, the developmental duration and survival rate of nymphs and the reproductive capacity of T. galchanoides fed on APD were observed in the laboratory, and the predation rates of nymphs and adults reared with APD were also investigated in the field. The results showed that there was no significant difference (P>0.05) in the developmental duration between T. galchanoides nymphs fed on APD (103.2±6.5 d) and on HWA (105.7±8.4 d). The survival rate of T. galchanoides nymphs fed on APD (73.2%) was lower than that fed on HWA (77.4%). The acquisition rates of T. galchanoides adults of the 1st, 2nd, and 3rd generations fed on HWA were the same with those fed on APD. There was no significant difference in pre-oviposition period, oviposition period, and oviposition amount between T. galchanoides adults fed on APD and those on HWA. Significant differences were found between the hatching rates of eggs laid by female adults fed on APD (85.8%) and HWA (71.4%), and in the longevity between female adults fed on APD (51.9±4.0 d) and HWA (37.4±2.6 d). T. galchanoides fed on APD preyed HWA effectively in the field. Thus, APD can be used for the mass rearing of T. galchanoides, which can be applied for biological control of HWA on a large scale.