【Aim】To elucidate the function of Niemann-Pick type C2 protein of Varroa destructor (VdesNPC2b) in host recognition by analyzing the binding properties and mechanisms of VdesNPC2b with the larval pheromones methyl oleate and β-ocimene of the host bees of V. destructor, so as to provide a theoretical basis for biological control of V. destructor. 【Methods】 The open reading frame (ORF) of VdesNPC2b was amplified and analyzed using bioinformatics. The prokaryotic expression vector was constructed based on pET-30a plasmid. The recombinant VdesNPC2b protein was obtained by prokaryotic expression and affinity column chromatography. The binding capacities of VdesNPC2b with the larval pheromones of bees methyl oleate and β-ocimene were analyzed by fluorescence competitive binding experiment, and the binding mechanism of them was analyzed by measuring the binding capacity change at two different temperatures (22 and 32 ℃) through fluorescence spectrum temperature variation experiment. The homologous modeling of VdesNPC2b was performed by SWISS-MODEL software, and the molecular docking simulation of VdesNPC2b and β-ocimene was performed by MVD to preliminarily analyze the key amino acid sites in the binding of VdesNPC2b and β-ocimene. 【Results】 The ORF of VdesNPC2b (GenBank no.: OR463903) is 531 bp in full-length, encoding 176 amino acids. VdesNPC2b has a signal peptide of 16 amino acid residues at the N-terminus. The fluorescent competitive binding assay result showed that the dissociation constant K_D values of VdesNPC2b with methyl oleate and βocimene were 2.89 and 3.49 μmol/L, respectively, with the binding process of dynamic quenching, and the main driving forces maintaining the interaction between VdesNPC2b and methyl oleate and β-ocimene was hydrophobic force. Homologous modeling showed that the secondary structure of VdesNPC2b is β-sheet, and forms a potential external cavity. Leu68, Ile103 and Phe107 could be the key amino acid sites to maintain a stable form of the binding of VdesNPC2b and β-ocimene. 【Conclusion】 V. destructor may use VdesNPC2b binding long-chain brood ester pheromone methyl oleate and volatile β-ocimene to locate and identify host honey bee.

【Aim】 Beauveria bassiana can indirectly affect phytophagous insect pests by colonizing plants. This study aims to determine the responses of feeding preference and olfactory response of the neonate and 3rd instar larvae of Ostrinia furnacalis to symbionts of aerial conidia (AC) and blastospore (BS) B. bassiana-corn. 【Methods】 Each corn plant was inoculated with 20 mL B. bassiana spore suspension (1.0×10⁸ spore/mL), soil drench inoculation was used to establish the B. bassiana-corn symbionts, including the B. bassiana AC treatment group and the B. bassiana BS treatment group. The feeding selection rates by the neonate larvae and 3rd instar larvae of O. furnacalis to the corn leaves of the B. bassiana-corn symbionts of AC and BS treatment groups under the choice and non-choice conditions were tested by a dish leaf disc method. The olfactory selection coefficient and olfactory selection response rate of the neonate and 3rd instar larvae of O. furnacalis to the corn leaves of the B. bassiana-corn symbionts of AC and BS treatment groups were detected by Y-type olfactometer. 【Results】 The test results of the dish leaf disc method showed that the feeding selection rate of both the neonate and 3rd instar larvae of O. furnacalis to the corn leaves of the B. bassiana-corn symbionts of AC and BS treatment groups were lower than that of the control group under the choice and non-choice conditions. The neonate larvae of O. furnacalis had the lowest feeding selection rate to the corn leaves of the B. bassiana-corn symbionts of BS treatment group under the choice condition, while the neonate larvae of O. furnacalis had no significant difference in the feeding selection rate to the corn leaves of the B. bassiana-corn symbionts of AC and BS treatment groups under the non-choice condition. The results of Y-type olfactometer test showed that the olfactory selection response rate of both the neonate and 3rd instar larvae of O. furnacalis to the corn leaves of the B. bassiana-corn symbionts in AC and BS treatment groups (olfactory selection coefficient<0) were significantly lower than that in the control group (olfactory selection coefficient>0), suggesting that the two types of B. bassiana spore colonized corn leaves have negative chemotaxis to O. furnacalis larvae. 【Conclusion】 This study confirms that there is an obvious avoidance effect of the corn leaves colonized by aerial conidia and blastospores of B. bassiana on the feeding behavior and olfactory behavior of O. furnacalis, which could provide a theoretical basis to utilize the endophytic colonization of B. bassiana for ecological control of insect pests.

【Aim】The aim of this study is to identify heat shock protein (Hsp) gene in Aphis gossypii(AgHsp90) and clarify the response of AgHsp90 to temperature, plant allelochemicals and insecticide stresses. 【Methods】RT-PCR and RACE were used to clone AgHsp90 of A. gossypii, and bioinformatics analysis was conducted. The expression levels of AgHsp90 in different developmental stages (1st-4th instar nymphs and adult) and in adults at 1 h after treatments with -5, 0, 5, 10, 15, 20, 30, 35, 38 and 42 ℃, and at 24 h after treatment with plant allelochemicals (20 mg/L tannic acid, 50 mg/L gossypol, 50 mg/L 2-tridecanone and 50 mg/L quercetin) and pesticide flupyradifurone stress［LC₂₅(2.410 mg/L)］ were quantified by qRT-PCR. RNAi of AgHsp90 and heat shock factor (HSF) gene AgHSF of A. gossypii adult was performed for 24 h through feeding method to determine the mortality rate of A. gossypii adults at 24 and 48 h after treatments with 50 mg/L gossypol and LC₄₀ (4.649 mg/L) flupyradifurone through feeding and leaf dipping methods, respectively, explore the effect of AgHsp90 on the susceptibility of A. gossypii to gossypol and flupyradifurone and preliminarily verify the mutual regulation between AgHsp90 and AgHSF. 【Results】One Hsp90 gene of A. gossypii designated AgHsp90 (GenBank accession no.: UOF38310) was obtained with a 2 181 bp ORF in length. The expression levels of AgHsp90 were relatively stable in different developmental stages, with the significant difference happened between the 3rd instar nymph and adult. Temperature stress experiment result revealed that AgHsp90 was obviously high temperature inducible, but low temperature downregulated the expression level of AgHsp90. The expression level of AgHsp90 in A. gossypii adult was not significantly induced by three plant allelochemicals (gossypol, tannic acid, and quercetin) and significantly induced by 2-tridecanone and LC₂₅ flupyradifurone compared with the controls 0.5 mol/L sucrose and Triton X-100, respectively. RNAi of AgHsp90 could remarkably increase the mortality rate of A. gossypii adult resulted from gossypol and flupyradifurone compared with the control fed with dsGFP. AgHsp90 and its transcription factor AgHSF could mutually affect the expression levels using RNAi method. 【Conclusion】 The heat shock protein gene AgHsp90 of A. gossypii is high temperature and flupyradifurone inducible. AgHsp90 is mostly associated with the gossypol and flupyradifurone susceptibility of A. gossypii. The above results indicate that AgHsp90 may play crucial roles in response to high temperature and pesticide flupyradifurone stresses.

【Aim】 To investigate the sublethal effects of abamectin on Sogatella furcifera. 【Methods】The 3rd instar nymphs of S. furcifera were treated with abamectin at LC₁0 (0.016 mg/L) and LC₂₅ (0.031 mg/L) concentrations using rice seedling dipping method. The longevity of female and male adults and the number of eggs laid per female of F₀ generation were recorded, and the developmental duration, fecundity, survival rate, female and male adult longevity, intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R₀), and mean generation time (T) of F₁ generation were recorded, and the age-stage, two-sex life table was established. 【Results】 After the 3rd instar nymphs of S. furcifera were exposed to LC₁₀ and LC₂₅ concentrations of abamectin, the number of eggs laid per female of the F₀ generation was significantly reduced, but the hatching rate was not affected as compared to the control (distilled water). Abamectin at the LC₂₅ concentration significantly prolonged the male adult longevity, whereas the female adult longevity was significantly shortened by the LC₁₀ of abamectin compared with the control. In addition, LC₁₀ and LC₂₅ concentrations of abamectin significantly reduced the number of eggs laid per female of the F₁ generation (LC₁₀: 170.64 grains; LC₂₅: 155.79 grains)  compared with the control (193.38 grains). In the LC₁₀ and LC₂₅ concentration treatment groups, the intrinsic rate of increase (r), finite rate of increase (λ) and mean generation time (T) of the F₁ generation were slightly lower than those in the control group, while the reproductive rate (R₀) showed a decreasing trend but not significantly different from that in the control. 【Conclusion】 Abamectin stress at the sublethal concentrations could somewhat inhibit the offspring population growth of S. furcifera.

【Aim】To study the effects of wavelength, intensity and treatment time of LED light on the activities of protective enzymes in Ectropis grisescens adults, so as to provide references for the green control of E. grisescens with light in tea garden.【Methods】The female and male adults of E. grisescens were exposed to LED light at the wavelengths of 590-595 and 520-525 nm under the light intensities of 40, 80 and 120 lx, respectively, in the laboratory, and the changes in the total protein content, activities of protective enzymes ［peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT)］, and total antioxidant capacity (T-AOC) were tested at 1， 2 and 3 h after treatments.【Results】 After exposure to LED light at the wavelengths of 590-595 and 520-525 nm, the total protein content, the activities of POD, SOD and CAT, and T-AOC in female and male adults of E. grisescens increased with the increase of light intensity and treatment time. At different time after exposure to LED light at the two wavelengths under various light intensities, the total protein content and POD activities in female adults were significantly higher than those in male adults, and the activities of SOD and CAT, and T-AOC in male adults were higher than those in female adults and those in female and male adults at 3 h under LED light intensity of 120 lx were the highest. The activities of POD, SOD and CAT in female and male adults of E. grisescens subjected to LED light radiation at the two wavelengths for different time was higher than those in the natural light control.【Conclusion】 LED light at the wavelengths of 590-595 and 520-525 nm can cause changes in the protective enzyme activities in E. grisescens adults, providing basic data for exploring the best wavelength, intensity and time of breaking protective enzyme activity and green control using light to irradiate pests in tea garden.

【Aim】To clarify the effects of ultraviolet radiation to the parasitized host pupa on the growth and development of the parasitoid Trichopria drosophilae, so as to provide a reference for the mass breeding of T. drosophilae. 【Methods】Three ultraviolet irradiation lamps, UVA, UVB and UVC, were used to irradiate the parasitized Drosophila melanogaster pupae in a dark box. The irradiation duration was 3, 6 and 9 h, respectively. The pupal mortality rate, egg-adult duration, adult emergence rate, sex ratio (female to male ratio), and longevity of T. drosophilae were observed and calculated. 【Results】Compared to the control, UVA irradiation showed no significant effects on the adult emergence rate, pupal mortality rate and female to male ratio of T. drosophilae. After UVB irradiation for 3, 6 and 9 h, and UVC irradiation for 3 and 9 h, the adult emergence rates of T. drosophilae decreased significantly and the pupal mortality rates increased significantly compared to the control. The female to male ratios of T. drosophilae irradiated by UVB for 3, 6 and 9 h were greater than 2.00. After UVA irradiation for 3 and 6 h, and UVC irradiation for 3, 6 and 9 h, the egg-female adult duration of T. drosophilae was significantly lower than that of the control. After UVC irradiation for 3, 6 and 9 h, the egg-male adult duration of T. drosophilae was significantly lower than that of the control. The female adult longevity of T. drosophilae raised with the increase of irradiation duration of UVA, but showed no significant difference between the UVA irradiation groups and the control. The female adult longevity in UVB irradiation for 6 h was significantly higher than that in the control. The male adult longevity of T. drosophilae in ultraviolet irradiation treatments was higher than that of the control, and the male adult longevity in UVA irradiation for 3 h, UVB irradiation for 6 h and UVC irradiation for 9 h exhibited significant difference from that in the control. 【Conclusion】Ultraviolet irradiation treatment on the parasitized D. melanogaster pupae can significantly affect the egg-adult duration and adult longevity of T. drosophilae. The results of this study provide a reference for the multiplication of natural enemy resources for biological control of Drosophila pests.