【Aim】 Estrogen-related receptors (ERRs) belong to the nuclear receptor (NR) superfamily and play an important role in regulating metabolism and energy conversion in insects. Bisphenol A (BPA) is related to insect reproduction and neurological diseases. This study aims to explore the mechanism of BPA affecting Drosophila melanogaster ERR (dERR). 【Methods】 The docking of small molecule BPA with dERR protein constructed by Modeller 9.25 was simulated by AutoDock Vina, the molecular dynamics simulation was carried out using Gromacs 5.1.9, and the binding mode of BPA and dERR was explored in combination with the calculation of binding free energy. qRT-PCR method was used to detect the effects of exposure of BPA at three concentrations (0.1, 1 and 10 μg/L) for 6, 12 and 24 h on the transcription levels of dERR gene in adults and the 2nd instar larvae of D. melanogaster. 【Results】 Based on molecular docking and polar solvation energy, it is found that side chain amino acids such as Phe370 and Leu334 are the key amino acids for the binding of BPA to dERR. qRT-PCR analysis showed that the transcription levels of dERR gene in adults and the 2nd instar larvae of D. melanogaster changed significantly at 6 and 12 h after treatment with BPA of different concentrations, but those of 0.1 μg/L BPA treatment were almost equal to those of the control at 24 h. 【Conclusion】 BPA can affect the expression of dERR in D. melanogaster, and the mechanism may be related to the potential specific binding of BPA and dERR. 

Key words: Drosophila melanogaster; BPA; estrogenrelated receptor; molecular docking; molecular dynamics simulation; qRT-PCR

【Aim】 This study aims to establish the transcriptome database of diapause eggs of Galeruca daurica, to reveal the genes and metabolic/signaling pathways related to egg diapause, and to explore the molecular mechanism of egg diapause at the transcriptomic level. 【Methods】 The Illumina NovaSeq 6000 platform was used to perform transcriptome sequencing and bioinformatics analysis of the diapause and diapause-terminated eggs of G. daurica. The DESeq software was applied to analyze the differentially expressed genes (DEGs) between the diapause and diapause-terminated eggs, and the DEGs were subjected to the KEGG pathway enrichment analysis. The expression profiles of 10 randomly selected DEGs were verified by qRT-PCR. 【Results】 According to the transcriptome sequencing results from the diapause and diapause-terminated eggs of G. daurica, a total of 53 389 unigenes including 2 145 DEGs were obtained, of which 24 DEGs are related to juvenile hormone signaling and fatty acid biosynthesis and degradation. Compared with those in the diapause-terminated eggs, 1 297 DEGs in the transcriptome of diapause eggs were up-regulated and enriched in 124 KEGG pathways, among which ribosome pathway was significantly enriched, and 848 DEGs were down-regulated and enriched in 73 KEGG pathways, among which MAPK signaling pathway and glycosaminoglycan biosynthesis were significantly enriched. The qRT-PCR analysis showed that the expression profiles of the 10 randomly selected DEGs were completely consistent with the RNA-Seq results based on the transcriptome data. 【Conclusion】 Pathways of juvenile hormone, fatty acid biosynthesis and degradation, ribosome, MAPK signaling and glycosaminoglycan biosynthesis may play important roles in the regulation of egg diapause in G. daurica.

【Aim】 In the previous studies it was found that the learning ability of Apis mellifera ligustica worker bees treated with imidacloprid is decreased, and transcriptomic analyses showed that the expression of major royal jelly protein 1 gene Mrjp1 is significantly down-regulated in the brains of bees treated with imidacloprid, suggesting that MRJP1 may be involved in olfactory learning in honeybees. This study aims to verify the crucial role of MRJP1 in olfactory learning in A. mellifera ligustica workers through silencing Mrjp1 by RNA interference (RNAi). 【Methods】 The cDNA sequence of Mrjp1 was obtained by cloning technique and validated by sequencing, and then the sequence was used for designing primers for generating dsRNA for knockdown of Mrjp1 by RNAi. The worker bees of A. mellifera ligustica injected with dsMrjp1 were assigned to the treatment group (dsMrjp1-injected group), and those injected with dsEGFP were assigned to the control group (dsEGFP-injected group). Then, the olfactory learning and memory abilities of the two groups were compared based on the proboscis extension response (PER) assay. Finally, the relative expression level of Mrjp1 in the brain of A. mellifera ligustica workers after injection of dsMrjp1 was detected by quantitative realtime PCR (qRT-PCR). 【Results】There was a significant difference in the learning ability of A. mellifera ligustica workers between the dsMrjp1injected group and the dsEGFP-injected group, with the learning ability of the dsMrjp1-injected group significantly decreased. However, there was no significant difference in the faculty of memory of A. mellifera ligustica workers at 2 h after learning between the two groups. The qRT-PCR results showed that the expression level of Mrjp1 in the brain of A. mellifera ligustica workers in the dsMrjp1-injected group was significantly lower than that in the dsEGFP-injected group, indicating that A. mellifera ligustica workers with decreased learning ability correspondingly exhibit lower expression level of Mrjp1. 【Conclusion】 After knockdown of Mrjp1 by RNAi, the olfactory learning performance of A. mellifera ligustica workers is significantly decreased, while their memory performance is not significantly affected, suggesting that Mrjp1 is probably one of the key genes regulating learning in A. mellifera ligustica. The results of this study contribute to further understanding of the molecular mechanism related to olfactory learning in honey bees.

【Aim】 To screen the high efficient delivery nanocarrier of dsRNA used for RNAi in Laodelphax striatellus. 【Methods】 Chitosan, carbon quantum dot (CQD), and lipofectamine 2000 were used as representative nanoparticles (NPs). The dsRNA loading efficacy of each NP was measured by spectrophotometry. The membrane-bound trehalase gene of L. striatellus, LsStre, was selected as the target gene to test the RNAi efficiency mediated by the three NPs. The mRNA expression levels of LsStre in the 2nd instar nymphs of L. striatellus at 2 d after being fed with dsLsStre mediated by different NPs were quantified by using real-time quantitative PCR (qPCR) strategy, and the corrected mortality rates induced by dsRNAs in 6 d were also detected and calculated. The synergic effects of the three NPs to RNAi of LsStre were evaluated based on the corrected mortality rates of the 2nd instar nymphs after RNAi with dsLsStre mediated by different NPs compared with that caused by naked dsLsStre (the control). 【Results】 All the three NPs could load dsEgfp, with the loading efficiencies of the three NPs coupled with dsEgfp all over 95%. All the three NPs showed low toxicity to the 2nd instar nymphs of L. striatellus. The qPCR results demonstrated that compared to the control group fed with naked dsLsStre not encapsulated with nanoparticles (causing 46% inhibition rate on the expression level of LsStre), chitosan and CQD significantly increased the RNAi efficiency of LsStre via feeding delivery, causing 78% and 84% inhibition rate, respectively, on the expression level of

LsStre, but lipofectamine 2000 could not significantly enhance the RNAi efficiency of LsStre, causing 52% inhibition rate on the expression level of LsStre. Moreover, the feeding assays also showed that chitosan and CQD significantly improved the dsLsStre-mediated lethal effect on the 2nd instar nymphs of L. striatellus. At 6 d after being fed with chitosan and CQD NP-dsLsStre conjugates, the corrected mortality of the 2nd instar nymphs of L. striatellus reached 76% and 82%, respectively, and the synergism ratios (SRs) of chitosan-and CQD-mediated RNAi groups were 2.17 and 2.34, respectively, compared with the control fed with naked dsLsStre (causing 35% corrected mortality). Meanwhile, lipofectamine 2000 was the most inefficient carrier for inducing RNAi in L. striatellus (SR=1.09), and lipofectamine 2000-dsLsStre conjugates caused 38% mortality of the 2nd instar nymphs of L. striatellus. 【Conclusion】 Chitosan and CQD nanocarriers are

more efficient to deliver dsRNA than lipofectamine 2000 in L. striatellus. The results are helpful in elucidating the RNAi efficacy boosted by NPs and provide a theoretical basis and practical strategies for developing and screening novel nanocarriers to realize the eco-friendly pest control.

【Aim】 The aim of this study is to determine the attractiveness of intestinal bacterium Klebsiella oxytoca to Drosophila suzukii, and to identify and verify the attractiveness of its volatile substances to D. suzukii adults. 【Methods】 The proportions of D. suzukii adults attracted by supernatants of K. oxytoca and NB medium (the control) as well as the proportions of female and male adults attracted in the presence or absence of host plant (Kyoho grape), respectively, were measured and analyzed. Volatile substances in the supernatant of K. oxytoca and NB medium were identified using HS-SPME-GC-MS methods. The attractiveness of four volatile substances of K. oxytoca supernatant with higher concentrations to D. suzukii adults was tested. 【Results】 D. suzukii adults were attracted to the supernatant of K. oxytoca. In the absence of host plant, the supernatant of K. oxytoca showed stronger attractiveness to male adults of D. suzukii than to female adults. However, in the presence of host plants, the numbers of female and male adults attracted by K. oxytoca supernatant were not significantly different. Twenty-one volatile substances were detected from K. oxytoca supernatant, among which 3-methyl-1-butyl alcohol, 2-phenylethyl alcohol, isoamyl acetate and indole had higher concentrations. D. suzukii adults showed taxis to 3-methyl-1-butyl alcohol, 2-phenylethyl alcohol and indole, but showed repellence to isoamyl acetate. The volatile substance 3-methyl-1-butyl alcohol could attract more male adults than female adults. 【Conclusion 】 Intestinal microorganism K. oxytoca supernatant can be used to attract D. suzukii adults, and 3-methyl-1-butyl alcohol is an important metabolite of K. oxytoca for attracting male adults of D. suzukii. This study provides some basic data for the control of D. suzukii.

【Aim】 Secondary endosymbionts may affect the susceptibility of Bemisia tabaci to insecticides. This study aims to reveal the influence of endosymbiont Cardinium infection on the insecticide tolerance of B. tabaci MED. 【Methods】 The tolerance of Cardinium-infected and uninfected lines with identical genetic background of two populations of B. tabaci MED (Lingshui population from Lingshui, Hainan Province, South China, and Shouguang population from Shouguang, Shandong Province, North China) to different concentrations of two neonicotinoid insecticides (thiamethoxam and imidacloprid) was assayed in the laboratory. 【Results】 After treatment with various concentrations of thiamethoxam and imidacloprid, respectively, the mortalities of the Cardinium-infected line of Lingshui population were significantly lower than those of the uninfected line. After exposure to 100, 150, 175 and 200 mg/L thiamethoxam and 175 and 200 mg/L imidacloprid, respectively, the mortalities of the Cardinium-infected line of Shouguang population were significantly higher than those of the uninfected line. Compared with the uninfected line, the resistance ratios of the Cardinium-infected line of Lingshui population under the pressure of thiamethoxam and imidacloprid were 1.355 and 1.847, respectively, while those of Cardinium-infected line of Shouguang population were 0.790 and 0.847, respectively. 【Conclusion】 Endosymbiont Cardinium infection can significantly influence the tolerance of B. tabaci MED to thiamethoxam and imidacloprid, and the influence varies among its different populations. The results provide valuable references for revealing the population adaptability and expansion mechanism of B. tabaci MED.

【Aim】 Spinetoram is one of the candidate pesticides most used for controlling the western flower thrips, Frankliniella occidentalis, on vegetables. This study aims to assess the effects of multigeneration spinetoram stress on F. occidentalis. 【Methods】 The 2nd instar nymphs of F. occidentalis were screened for six generations with LC₂₅ dosage of spinetoram by the leaf dipping method, and the insecticide sensitivity and detoxification enzyme activities in the nymphs were determined. The agestage twosex life table was used to analyze the effect of LC₂₅ dosage of spinetoram on the life table parameters of F. occidentalis offspring (F₇). 【Results】 After the 2nd instar nymphs of F. occidentalis were selected with LC₂₅ dosage of spinetoram for six generations, the resistance ratio increased to 6.4 folds as high as that of the control treated with water. CarE and GSTs in the day-2 2nd instar nymphs of F₆ generation were significantly activated, with their activities 1.26 and 1.21 folds as high as those of the control, while MFOs and P450s were significantly inhibited, with their activities only 54.00% and 51.78% of those of the control, respectively. When the 2nd instar nymphs of F. occidentalis were selected with LC₂₅ dosage of spinetoram for six generations, the longevity (19.33 d) and fecundity (69.80 eggs) of female adult significantly decreased as compared to those of the control (21.60 d and 83.17 eggs, respectively), the female adult longevity (16.82 d) and male adult longevity (8.29 d) of F₇ generation were also significantly shortened as compared to those of the control (20.28 d and 10.86 d, respectively), the fecundity of F₇ generation (59.23 eggs laid per female) extremely significantly decreased as compared to that of the control (76.96 eggs laid per female), but the female to male sex ratio (2.28) significantly increased as compared to that of the control (1.03). The net reproductive rate (R₀), intrinsic rate of increase (r) and finite rate of increase (λ) in F₇ generation of F. occidentalis after selection with LC₂₅ dosage of spinetoram for six generations had no significant change. 【Conclusion】 The resistance of F. occidentalis to spinetoram

increases slowly within six generations under selection by LC₂₅ dosage of spinetoram. Spinetoram stress not only causes significant changes in the detoxification enzyme ctivities in F. occidentalis, but also inhibits its development and reproduction.

【Aim】 The transgenic Bt cotton and poplar have been widely used in China. The aim of this study is to investigate and analyze the composition and diversity of the above-ground arthropod community in the transgenic poplar-cotton composite system, so as to provide basic data for the application of transgenic poplar. 【Methods】  Two popla-cotton composite systems, transgenic poplar-transgenic cotton (composite system 1) and non-transgenic poplar-transgenic cotton (composite system 2), were constructed at a farmland in Renqiu City of Hebei Province, North China. The transgenic cotton (Gossypium hirsutu) plants were planted under the newly planted poplar (Populus nigra). The composition (the species and number of individuals) and diversity indexes (Shannon-Wiener index, dominance concentration index and Pielou index) of arthropod community on polar and cotton plants in the two poplarcotton composite systems were investigated from April to October in 2019. The dynamics of Bt insecticidal protein content in leaves of transgenic poplar and cotton was also detected.【Results】 The numbers of individuals of lepidopteran pests both on transgenic poplar and cotton plants in composite system 1 were significantly lower than those on the corresponding plants in composite system 2. The number of individuals of leaf beetles on transgenic poplars was significantly higher than that on non-transgenic poplars, while the number of individuals of parasitic wasps on transgenic poplars was significantly lower than that on nontransgenic poplars. The Shannon-Wiener index of the arthropod community on transgenic poplars was significantly higher than that on non-transgenic poplars on June 5, June 21, and September 7. The numbers of various functional groups of arthropod communities except Lepidoptera on cotton plants in the two composite systems had no significant difference. The Shannon-Wiener index, dominance concentration index and evenness index of arthropod community on cotton plants in the two composite systems had the similar dynamic trend, and showed no significant differences at the same investigation time. The only exception was the Shannon-Wiener index on August 17, which was significantly higher on cotton plants of composite system 1 than on cotton plants of composite system 2. The cumulative numbers of various functional groups from cotton and polar plants were summed and analyzed as the whole composite system, and the result showed that there was no significant difference in Shannon-Wiener index, dominance concentration index and evenness index of arthropod community between composite system 1 and compositesystem 2. Arthropod  populations were aggregated to poplar leaves during the late investigation period. The Bt insecticidal protein contents on transgenic cotton plants were extremely higher than those on transgenic poplars through the whole growth season. 【Conclusion】 The transgenic poplar can control target insects, and have a synergistic effect against lepidopteran pests on cotton. The community structure of above-ground arthropods in the transgenic poplar-cotton composite system is stable, without significant effect on the diversity of the above-ground arthropod community on cotton plants. It is necessary to persistently detect and monitor the development of insect resistance to transgenic Bt poplar.

【Aim】 Invasive species can affect the biodiversity of an invasive site by influencing native species populations through competition. Anoplolepis gracilipes is one of the most destructive invasive ants in the world. This study aims to identify the competitive relationship between A. gracilipes and a dominant indigenous ant species Oecophylla smaragdina in Xishuangbanna, southwestern China. 【Methods】 By combining field investigation and the controlled experiment, the body size, the patterns of foraging activity outside the nest in cold fog season and rainy season, the foraging ability (foraging time and the maximum number of recruited workers within foraging time), the fighting behavior (attack intensity and mortality in different fighting combinations), and the starvation and thirst tolerance (the mean survival time and survival rate along time when no food and water were supplied) between A. gracilipes and O. smaragdina were observed and comparatively analyzed. 【Results】 The body length of A. gracilipes workers (3.66±0.06 mm) was significantly smaller than that of O. smaragdina workers (8.27±0.16 mm). The foraging time of A. gracilipes was longer than that of O. smaragdina in the fog cold season, while the numbers of foraging individuals of both species decreased in the high temperature period of the afternoon in the rainy season. When three different foods (apple, bee honey and sausage) were used as the bait, A. gracilipes only needed 4-8 min to find food, while O. smaragdina needed 8-21 min to find food. After finding food, A. gracilipes workers had the ability to gather their companions faster than O. smaragdina. In the controlled experiments, no attack or low intensity attack occurred predominantly in the combination of one individual of A. gracilipes with one individual of O. smaragdina, and when the number of individuals of either of the two species increased to five, the fighting intensity increased significantly, and both species exhibited intraspecific cooperation. There was no significant difference in the average survival time of workers between the two species under starvation and thirst, but A. gracilipes could survive for 120 h, while O. smaragdina could only survive for 96 h. 【Conclusion】 A. gracilipes exhibits stronger ability to forage and longer activity duration in the fog cold season than the indigenous ant species O. smaragdina in Xishuangbanna, suggesting that A. gracilipes may have strong temperature adaptability. It is necessary to intensify the research on this invasive species, and its population development in this area should be paid close attention to.

【Aim】 The aim of this study is to clarify the phylogenetic status of the tribe Sinosenini in Cicadoidea, in which the cicadas have no timbal organs. 【Methods】 Based on adult specimens of Karenia caelatata of Sinosenini collected in Ningshan, Shaanxi, northwestern China, the mitochondrial genome of K. caelatata was sequenced, annotated, bioinformatically analyzed, and compared with the mitochondrial genomes of other taxa of Cicadoidea. Molecular phylogenetic trees for Cicadoidea were constructed using both maximum likelihood (ML) method and Bayesian inference (BI) method. 【Results】 The mitochondrial genome of K. caelatata (GenBank accession number: MN922304) is 14 960 bp in length, and the gene organization, nucleotide composition and codon usage of proteincoding genes display similar structural characteristics to those of other taxa of Cicadoidea. Analysis of nucleotide diversity reveals that genes atp8, nad6 and nad2 are highly variable, while cox1 is more conserved. Ratios of nonsynonymous and synonymous substitution rates indicate that the evolution of mitochondrial genomes in Cicadoidea is under a highlevel purifying selection. Results of phylogenetic analyses support the monophyly of Cicadomorpha, revealing the relationship of the three superfamilies of this infraorder as (Membraciodea+(Cicadoidea+Cercopodidea)). Karenia is clustered with representatives of the tribe Dundubiini in the subfamily Cicadinae and most closely related to the genus Meimuna. Mogannia and Vagitanus, representatives of Cicadatrini, are clustered with the members of Cicadettinae. Yezoterpnosia is not a monophyletic group. 【Conclusion】 Sinosenini should be transferred from Cicadettinae to Cicadinae and merged with Dundubiini, while Cicadatrini should be transferred from Cicadinae to Cicadettinae. Our results provide new information for future study of evolution of cicadas with different sound-producing mechanisms.

Insect oral secretion (OS), also known as vomit, is a mixture of saliva secreted by salivary glands and secretions secreted by guts in insects. During insect feeding on host plants, OS is secreted into plants and affects plant defense responses. RNA interference (RNAi) is a valuable reverse genetics tool to study insect gene function and also a new technology to be used in pest control. In this article, we mainly reviewed the effects of insect OS on host plant defense, the identification of insect OS effectors and the feasibility and application of OS effectors based on RNAi technology in pest control. Insect OS affects host plant defense mainly by interfering with jasmonic acid signalingpathway, sieve tube obstruction, and  Ca²⁺ pathway and other defense responses in host plants, and then promotes insects to ingest food. At present, the main methods of identification of insect OS effectors are based on the transcriptomic analysis of insect salivary glands and proteomic analysis of OS. Most of the OS effectors have been identified from insects with sucking mouthparts, and less reported in insects with chewing mouthparts. The functional studies revealed that the expression of insect OS effectors in host plants can affect the survival rate, fecundity, and feeding ability of insects and other important physiological indexes of both insects and plants. By identifying the interaction between OS effectors and plant defense mechanisms, the roles of OS effectors in the relationship between insects and host plants have been further demonstrated. Based on RNAi technology, the expression levels of OS effector genes are downregulated, and the growth and development are affected in many insects by microinjection-, feeding-, and plant-mediated RNAi using OS effector genes as targets, suggesting that OS effector genes could be used as RNAi targets. Although the studies are still in the laboratory stage, their application in pest control has been proven to be feasible in certain degree. Insect oral secretions are a new direction to study the interaction mechanism between insects and host plants. Finally, the future research directions of OS have been prospected, hoping toprovide some theoretical guidance for studies of pest control in China.