Odorant binding proteins (OBPs) are widely involved in olfactory perception and play a key role in transporting hydrophobic odorants across the sensillum lymph to the olfactory receptors (ORs). Understanding the roles of insect OBPs in chemical communication would help us elucidate the mechanism of insect olfaction perception and lay the theoretical basis for controlling the target pests by interfering with insect chemoreception. In this study, a novel OBP gene AlucOBP7 (GenBank accession no.: JQ675724) was identified from the green plant bug, Apolygus lucorum (Meyer-Dür), and then the recombinant AlucOBP7 was prokaryotically expressed in Escherichia coli and purified. Fluorescence competitive binding assays were conducted to explore the binding properties of AlucOBP7 with 10 cotton volatiles and 6 sex pheromone analogs using a fluorescence probe, N-phenyl-1-naphthylamine (1-NPN). The results revealed that for the 10 cotton volatiles, AlucOBP7 showed certain binding abilities with 2-hexanone and methylis salicylas, with the dissociation constants of 55.13 μmol/L and 28.26 μmol/L, respectively. For the 6 sex pheromone analogs, the AlucOBP7 had a strong binding affinity with 4-oxo-(E)-2-hexenal, with the dissociation constant of 23.14 μmol/L. Ethyl butyrate, butyl butanoate and hexyl hexanoate showed moderate binding abilities with AlucOBP7, and their dissociation constants were 30.58, 39.26 and 35.81 μmol/L, respectively. We so inferred that AlucOBP7 may be a pheromone binding protein of the green plant bug and play dual roles in the perception of sex pheromone and plant volatiles.

Vitellogenin receptor (VgR) is one of the key factors during the uptake of vitellogenin (Vg) by oocytes, and plays a critical role in vitellogenesis and oocyte development. In order to define the physiological function of VgR, VgR cDNA in the whitefly, Bemisia tabaci Middle East-Asia Minor 1 (MEAM1) was sequenced using the combined methods of reverse transcription PCR (RT-PCR) and rapid amplification of cDNA ends (RACE). The bioinformatical analysis demonstrated that the full-length cDNA of VgR from B. tabaci MEAM1 is 5 774 bp in size. The putative mature VgR has 1 919 amino acids with a molecular weight of 201 kDa. The signal peptide at the N-terminal end contains 31 amino acids. The VgR of this whitefly has all the typical conserved domains of the low density lipoprotein receptor (LDLR) family. The expression profile of VgR gene at different developmental stages of the whitefly was detected by realtime quantitative PCR. The results showed that the expression of VgR gene was initiated at the pseudo-pupal period and increased rapidly on the 1st day after eclosion and reached the peak level on the 7th day after eclosion. These results will enrich the gene database of VgR and provide valuable information to ascertain the regulation mechanism of vitellogenesis in B. tabaci.

Phenoloxidase is the key enzyme of melanin synthesis and insect immunity, usually existing in the form of prophenoloxidase. In order to study the genetic differentiation and immune defense, a prophenoloxidase gene Tm-ppo was cloned from the larvae of yellow and black color varieties of Tenebrio molitor, bioinformatics of the cDNA and the encoded amino acid sequence of Tm-ppo was analyzed, and the mRNA levels in different developmental stages of the two varieties were examined by PCR, RACE and realtime quantitative PCR. The results showed that the full cDNA sequences of Tm-ppo cloned from the yellow- and black-color varieties of T. molitor are both 2 199 bp in length. Their base sequence identity is 99%. Both contain a 2 055 bp open reading frame encoding 684 amino acid residues. Because of three amino acid variation (P176→A176, V256→A256 and I648→M648) existing between the two proteins encoded by the two cDNA sequences, they were considered two isoforms of Tm-ppo, i.e., Tm-ppo-1  (GenBank accession number: JX987235) and Tm-ppo-2 (GenBank accession number: JX987234), respectively. Both prophenoloxidase protein isoforms (Tm-PPO-1 and Tm-PPO-2) encoded by Tm-ppo-1 and Tm-ppo-2 have a possible prophenoloxidase proteolytic activation site located between the amino acid residues of R50 and F51, and a di-copper binding centre appearing at residues of 196-239 and residues of 344-411, respectively. In addition, they contain a thiol ester region-like motif (residues of 579-588) and a C-terminal conserved motif (residues of 634-645). But they have neither a hydrophobic N-terminal signal sequence nor a transmembrane domain. The secondary structure of Tm-PPO-1 and Tm-PPO-2 consists of many alpha helices, beta sheets and random coils, and their tertiary structure can be divided into 4 functional domains: the pro-region (residues of 16-66), the noncontiguous domain Ⅰ (residues of 3-15 and 67-181), domain Ⅱ (residues of 182-419) and domain Ⅲ (residues of 420-679). Transcripts of Tm-ppo-1 and Tm-ppo-2 were evidently present in every developmental stage of the yellow and blackcolor varieties of T. molitor and the mRNA levels in each stage varied in the descending order of larval stage﹥adult stage﹥pupal stage. Environmental temperature had a significant effect on the mRNA expression of Tm-ppo-1 and Tm-ppo-2. The mRNA levels were all downregulated in larvae, pupae and adults of both color varieties with exposure to 42℃ for 24 h and 48 h, compared with those in the control insects under 25-30℃. The Tm-ppo-2 mRNA level in larvae and adults of blackcolor variety was higher than the Tm-ppo-1 mRNA level in larvae and adults of yellow-color variety, while the mRNA expressed in pupae of both color varieties showed no significant difference under the same test conditions. This study may provide a useful reference to further inquire into genetic differentiation and immune defense in T. molitor.

In order to study the function of ecdysone receptor in the diapause of Sitodiplosis mosellana, the full length cDNA sequence of an ecdysone receptor gene was amplified by using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE), and the expression of the EcR gene was analyzed using real-time quantitative PCR (qPCR). The full-length cDNA sequence was named as SmEcR (GenBank accession number: KC491135). Its open reading frame (ORF) is 1 386 bp in length, encoding a 461 amino acid protein, with a calculated molecular weight of 52.90 kD and the theoretical isoelectric point of 6.24. Multiple sequence alignment revealed that the deduced amino acid sequence of SmEcR has high identity with EcRs from other insect species, especially with that of Bradysia coprophila (92%). Real-time quantitative PCR showed that SmEcR transcripts were detected in all diapause and developmental stages. The expression of SmEcR was significantly different among different diapause stages, reaching the highest level in November and the lowest level in December. The larvae collected from wheat heads had a lower expression level of SmEcR while the adults had the highest SmEcR transcripts. This study lays the foundation for the further functional study of SmEcR in diapause regulation in S. mosellana.

In order to study the function and binding characteristics of the odorant-binding proteins (OBPs) in the oriental fruit fly, Bactrocera dorsalis, we cloned an OBP cDNA from B. dorsalis, which was named BdorOBP2 (GenBank accession no.: KC773766), and then heterologously expressed its protein in prokaryotic cells. BdorOBP2 contains a 447-bp open reading frame (ORF) encoding 148-amino-acid residues. The mature protein of BdorOBP2 includes six conserved cysteine residues, which are the hallmark of insect OBPs. Real-time quantitative PCR results showed that BdorOBP2 was expressed in different tissues with the highest expression in the head and the lowest in the wings (63%±6% of the expression level in the head). The recombinant protein BdorOBP2 was purified by affinity chromatography, and N-phenyl-1-naphthylamine (1-NPN) was applied as a fluorescent probe to measure the binding capacity of BdorOBP2 with each of seven major host fruit odors. The results indicated that BdorOBP2 can evidently bind to most esters and aldehydes examined. BdorOBP2 showed the highest affinity to trans-2-hexenal and β-ionone with the dissociation constant KD of 9.96 and 15.37 μmol/L, respectively. The results of this study may help rational designs of specific and effective attractants to be used for managing B. dorsalis.

In order to understand the endocrine control mechanism of physiological trade-offs between flight muscle and reproductive development, the effects of application of juvenile hormone III (JH-III) and precocene I (P-I) on flight muscles and reproductive development were examined in the wing dimorphic cricket Velarifictorus ornatus. The results indicated that  at 7 d after the JH-III and P-I were injected into the test adults on the day of their emergence, the application of juvenile hormone promoted ovarian development in long-winged female V. ornatus. The weight of ovaries of crickets injected with 1, 5, 10 and  25 μg JH-III were 43.9±10.7, 33.6±14.0, 56.8±7.6 and 39.3±30.7 mg/♀, respectively, which were significantly heavier than that of the control group. The application of juvenile hormone stimulated ovarian development but did not affect the number of eggs in the ovary of long winged females significantly. On the contrary, the application of JH-III stimulated the degradation of flight muscles. The weight of flight muscles of crickets treated with 1, 5 and 10 μg JH-III decreased to 12.9±4.7, 11.7±4.8 and 8.8±0.8 mg/♀, respectively, which was lighter than that of the control group. Injection of P-I restrained the ovarian development of short-winged female V. ornatus when the dosage was over 50 μg, but had no effect when the dosage was lower. There was no difference in the development of the testes, accessory glands, and flight muscles of long-winged males injected with acetone and juvenile hormone. Injection of P-I did not influence the development of the testes, accessory glands, and flight muscles of the short-winged males. Therefore, hormonal control of flight muscles and reproductive organ development appears to differ between female and male wing dimorphic crickets.

To understand the roles of larval density in the cellular immunity of the beet webworm, Loxostege sticticalis L. (Lepidoptera: Pyralidae), the types, number and composition of hemocytes in its 5th instar larvae reared on intact plants of Chenopodium album L. at the density of 1, 5, 10, and 20 larvae/jar (900 mL) were investigated. Five types of hemocytes were identified from larval L. sticticalis, i.e., prohemocytes, granular hemocytes, plasmatocytes, spherulocytes and oenocytoids. The numbers of plasmatocytes, granular hemocytes and total hemocytes increased as the larval density increased, but the numbers of prohemocytes, spherulocytes, and oenocytoids were insignificantly affected by the larval density. The proportion of each hemocyte type to the total haemocetes ranked in a similar order in the four treatments but the ratios of plasmatocytes at the density of 10 and 20 larvae/jar were remarkably higher than that of the isolated larvae. These results suggest that the larval density can affect the number of plasmatocytes and granular hemocytes, and this impact in turn can affect the cellular immune capacity in larval L. sticticalis.

To investigate the resistance level of Helicoverpa armigera (Hübner) from transgenic Bt cotton field to insecticides and ascertain their biochemical mechanisms, three field populations were collected in 2011 and 2012 from southern suburbs of Baoding, Nanpi County of Cangzhou and Julu County of Xingtai in Hebei Province, North China. The toxicity of eight insecticides was tested by topical application method, and the activities of the related carboxylesterase (CarE), glutathione S-transferases (GSTs) and acetylcholinesterase (AChE) were determined by biochemical analysis. The results showed that the three field populations had medium- or high-level resistance to betacypermethrin and fenvalerate (the R/S ratio: 20.02-73.70), low- or medium-level resistance to methomyl ( the R/S ratio: 6.27-11.84), but were sensitive to lambda-cyhalothrin (the R/S ratio: 1.07-4.20), phoxim, chlorpyrifos and malathion (the R/S ratio: 1.00-2.69), and chlorantraniliprole (the R/S ratio: 2.00-3.67). The activities of CarE, GSTs and AChE in the three field populations were 1.06-1.23, 1.20-1.63 and 1.15-1.23-fold as high as that in the susceptible population, respectively, and this may be correlated with the resistance to betacypermethrin, fenvalerate and methomyl.

 Plant viruses can induce changes in plant morphology and physiology, which may affect the performance of the insect vectors and parasitoids. However, the impact of plant viruses has been rarely considered in the research of this type of plant-vector-parasitoid interactions. In this study, we tested and analyzed the effects of the begomovirus, tomato yellow leaf curl virus (TYLCV), on the leaf trichome density of tomato and the foraging performance and fitness of the whitefly parasitoid, Eretmocerus hayati Zolnerowich and Rose. Our results showed that viral infection of tomato led to a significant increase of leaf trichome density, which in virus-infected plants was 1.8 times as high as that in uninfected plants. The host handling time and patch residence time of the parasitoid on virus-infected plants were 2- and 1.5-fold as high as that on uninfected plants, respectively. However, the parasitism rates, emergence rates and developmental durations of the parasitoid on infected and uninfected plants were similar. This is the first report of begomovirus-induced increase of plant leaf trichomes and its effects on a parasitoid, and it provides new data for understanding the interactions between plants, begomoviruses, whiteflies and parasitoids.

【Aim】 The purpose of the paper is to determine the distribution of Bemisia tabaci biotypes and their infection status of tomato yellow leaf curl virus (TYLCV) in Xinjiang, northwestern China. 【Methods】 Mitochondrial cytochrome oxidase I (mtDNA COⅠ) gene sequences and two pairs of primers (TYLCVF/TYLCV-R and PA/PB) were utilized to identify biotypes of B. tabaci and to detect the status of carrying tomato yellow leaf curl virus (TYLCV). 【Results】 The results showed that samples collected from Shihezi city, Bole city, Yopurga county, Zepu county, Karghalik county, Shache county, Karakash county, Hotan city and Hotan county belong to the B biotype, and these samples showed 100% identity of the 720 bp COⅠ sequences examined with the references. Samples from Aksu city, Hami city, Shanshan county, Urumqi city, Karamay city and Yining city belong to the Q biotype, and their COⅠ sequence identities were 99.9%-100%. Both B biotype and Q biotype occurred in Turpan and Korla cities. TYLCV were detected in samples collected from Yining city, Urumqi city, Shanshan county, Hami county, Aksu city, Korla city, Shache county, Hotan county and Karakash county, and all these areas were in high risk of TYLCV occurrence except Shache county where TYLCV had already broken out in late 2011. 【Conclusion】 This study provides scientific basis for the control of Bemisia tabaci and the outbreak of TYLCV in Xinjiang.

【Aim】 To explore the indirect effects of UV-B radiation on the life table parameters and feeding behavior of Sitobion avenae (Fabricius). 【Methods】 Age-specific life table was established to evaluate the life table parameters. The effect on feeding behavior of S. avenae was studied using electrical penetration graph (EPG). 【Results】 The results revealed that the life table parameters such as the intrinsic rate of increase (r_m), the net rate of increase (R₀), fecundity (F) and the mean length of a generation (T) of S. avenae feeding on the wheat exposed to the high-intensity (0.75 mW/cm²) UV-B radiation were significantly lower than those in the control (S. avenae feeding on the wheat grown under fluorescent lamp). The corresponding parameters tested in the low-intensity (0.2 mW/cm²) UV-B radiation group were basically identical with that in the control group. Similarly, compared with the control group, the number of np waveform increased and the duration time of C wave prolonged significantly in the highintensity UV-B radiation group. The results indicated that the difficulty of feeding behavior for S. avenae was elevated and the effective feeding time decreased due to the UV-B irradiation. Although the time for the first occurrence of pd waveform was not significantly different between the lowintensity UV-B radiation group and the control group, it was delayed in the two UV-B treatment groups. 【Conclusion】 High-intensity UV-B stress on wheat could undermine the growth, development and feeding behavior of S. avenae.

In order to reveal the effects of temperature on the growth and development of Pyralis farinalis (Linnaeus) on host plant Litsea coreana, one insect used for producing insect tea in China, a laboratory experiment was conducted to study the mean developmental duration, developmental rate, and survival rate of P. farinalis at 31, 28, 25, 22 and 19℃. The developmental threshold temperature and effective accumulated temperature of P. farinalis in egg, larval, pupal and immature stages were also calculated. The results showed that temperature had significant effects on the developmental duration, developmental rate and survival rate of P. farinalis. The developmental duration of egg, larva, pupa and immature stage of P. farinalis reduced with increasing temperatures from 19 to 31℃, and was the shortest at 31℃, being 4.56±0.24, 43.33±1.50, 7.89±0.20 and 55.78±1.69 d, respectively. There also existed remarkable significant quadratic regression relationships between the temperature and developmental rates of P. farinalis. In addition, the temperature had significant effects on survival rate of P. farinalis. The survival rate of eggs was the highest at 28℃, being 93%, while those of larvae and pupae were the highest at 25℃, being 88% and 93%, respectively, and excessively high or low temperature was unfavorable to its survival. Based on the direct optimal method, the developmental threshold temperatures of P. farinalis in egg, larval, pupal and immature stages were 13.30, 15.48, 13.19 and 14.82℃, respectively, and the corresponding effective accumulated temperatures were 88.36, 679.51, 159.73 and 952.04 day-degrees, respectively. The results provide a basis for rearing P. farinalis and are applicable in productive practice of insect tea.

We compared the phytase transgenic maize and its isogenic maize to examine the effect of phytase transgenic maize on the carabid beetles in the growing seasons (June to September) of 2012. Using the pitfall traps, beetles were collected from 12 plots along six replicated blocks for each maize. Each block was composed of two plots which were planted with phytase transgenic maize and its isogenic maize, respectively. Two sample locations with five traps for each location were set in each plot, and traps were emptied twice each month. A total of 8 012 specimens were collected, belonging to 7 genera and 23 species. Chlaenius micans represented 87.54% of the total capture and was the most abundant species. Dolichus halensis, Chlaenius posticalis and Scarites terricola occupied 34.77%, 31.16% and 6.21% of the total specimens, respectively, when the individuals of C. micans were excluded, and were also considered as common species in this study. Most carabid beetles showed a similar pattern in seasonal changes in phytase transgenic maize. There were no significant differences in richness, abundance, Shannon-Winner diversity index and evenness index of carabid beetles between phytase transgenic maize and its isogenic maize. Repeated ANOVA analysis showed that C. posticalis had significantly higher abundance in phytase transgenic maize compared with its isogenic maize, but other abundant species did not show significant differences between the two maize fields. Multivariate analysis (NMDS) also indicated that high similarity in carabid assemblages were shared between phytase transgenic maize and its isogenic maize. These results suggest that phytase transgenic maize has no significantly adverse effect on carabid beetles.

Phenacoccus solenopsis Tinsley, a new invasive species in China, is a worldwide pest causing serious threat to the production of agriculture and forestry. Morphological identification of this mealybug species is limited by high degree of similarity and polymorphism. In the present study, a method was described for the development of DNA markers for rapidly identifying P. solenopsis. A pair of universal primers was designed based on published mitochondrial DNA cytochrome c oxidase subunit Ⅰ (mtDNA COI) gene sequences of mealybugs in GenBank. The mtDNA COI genes from P. solenopsis and seven other mealybug species common in China including Pseudococcus comstocki Kuwana, Planococcus lilacius Cockerell, Maconellicoccus hirsutus (Green), Saccharicoccus sacchari (Cockerell), Dysmicoccus neobrevipes Beardsley, Planococcus minor Maskel and Phenacoccus solani Ferris were amplified and sequenced. And then one pair of species-specific COI (SS-COI) primers was designed. The SS-COI primers amplified a single band of 546 bp from P. solenopsis. The specificity of the primer pair was validated using the seven other mealybug species mentioned above. The results showed that all and only P. solenopsis specimens were detected, and no cross reactions with other mealybugs were observed. The method was tested with individuals of the egg, 1st, 2nd and 3rd instar nymph and female adult, and demonstrated to be applicable for all life stages. Furthermore, the primer set was tested with one P. solenopsis population from Pakistan and fourteen P. solenopsis populations from invaded areas in China and proved to be applicable for all geographic populations. The diagnostic PCR assay developed here provides a quick, simple and reliable molecular technique for the identification and monitoring of P. solenopsis, which will be useful in intercepting and blocking the further spreading of P. solenopsis.

Autophagy is a ubiquitous phenomenon of intracellular selfdegradation in living organisms. In order to recycle cellular substances during autophagy, cytoplasmic aggregates and organelles are engulfed into doublemembrane autophagosomes and finally delivered to lysosomes for degradation. Autophagy is initiated as an adaptive response for cell survival in unfavorable conditions, such as starvation, anoxia, endoplasmic reticulum stress, pathogen invasion and aggregation of dysfunctional proteins, while extensive autophagy can act as an initiator and executor of programmed cell death (PCD). Although the molecular assembling of autophagosomes and induction of autophagic pathway have been extensively documented, it is hard to reach a consensus on some important issues. In this review, we summarized and discussed the biological significance of the occurrence of autophagy and the source of autophagosomal membrane in insects. Under the circumstance of mild starvation, low level of autophagy will be induced to activate basal metabolism and to maintain cell survival. Challenged with excessive starvation during the feeding phase or stimulated by ecdysone during metamorphic development, high level of autophagy and apoptosis are triggered in larval tissues which will undergo irreversible cell death. Starvation causes delays of larval growth and development and eventual lethality, while 20E result in molting and degradation of larval tissues. Different from the pioneering studies in yeast and vertebrates, there are still not enough documented evidences to address whether pathogenic invasion can stimulate low level of autophagy in insect cells. The issue that almost all of the organelles-derived membrane can serve to be the source of autophagosomal membranes remains to be further investigated.

In order to improve the biological activities (LC₅₀ and LT₅₀ values) of two geographic isolates of Helicoverpa armigera nucleopolyhedrovirus (EAZ-I and EAZ-II), collected from East-Azarbaijan, Iran, some optical brighteners have been combined with the isolates under laboratory conditions to test their activity against early 2nd instar larvae of H. armigera. The results demonstrated that the EAZ-I isolate had better insecticidal activity than EAZ-II due to its lower LC₅₀ and LT₅₀ values of 1.98×103 OB/mL and 122.7 h, respectively. All the optical brighteners used in this study could efficiently enhance virus biological activities, especially Tinopal F-3543 in combination with EAZ-I showing the lowest LC₅₀ at 0.2% level (5.16×102 OB/mL), with 3.84 times higher activity than that of the virus alone. The relative speed of kill demonstrates that all the optical brighteners improved LT50 of the isolates, of which Tinopal F-3543 was identified as the most effective one. These findings suggest that the optical brighteners which target PM permeability can be considered as important alternatives to combine with HearNPV formulations in IPM programs.