【Aim】 Ras signaling pathway palys an important role in cell proliferation and growth in Drosophila. Myc, a member of basic helix-loop-helix (bHLH) transcription factor family, regulates physiological processes such as cell growth, competition and tissue regeneration. The aim of this study is to clarify the interaction between Ras signaling and Myc, and to explore the mechanism how Ras signaling regulates the growth of endoreplication cells. 【Methods】 The transcription level of Myc in posterior silk glands of transgenic silkworm (Bombyx mori) was analyzed by bioinformatics tools and detected by qPCR. Ras^V12 or Raf wereoverexpressedby transfecting pAc5.1-HisB-Ras^V12-V5 or pAc5.1-HisB-Raf-Flag plasmid into Drosophila melanogaster Kc cells, respectively, and the mRNA and protein expression levels of Myc were detected by qPCR and Western blotting, respectively. The functions of Ras signaling in regulation of Myc in larval fat body and salivary glands of D. melanogaster were verified by using D. melanogaster genetic tools and molecular biology methods. 【Results】 Overexpression of Ras1CA in silkworm posterior silk glands up-regulated Myc transcriptional level. Activation of Ras signaling up-regulated Myc expression at both the transcriptional and protein levels in D. melanogaster Kc cells. In salivary glands and fat body of D. melanogaster larva, the expression levels of Myc at the wandering stage were higher than those at the feeding stage. Overexpression of Myc or activation of Ras signaling accelerated endocycling. Activating Ras signaling promoted Myc expression.【Conclusion】 The Ras signaling pathway can activate the expression of Myc, thereby accelerating the endocycle and promoting organ development.

【Aim】 Starvation is one of the main stress signals for organisms in their developmental cycle. The purpose of this study is to understand how the silkworm (Bombyx mori) adjusts the metabolism conditions to survive after starvation and to explore the role of forkhead box transcription factor O gene (FoxO) in this process. 【Methods】 The 5th instar day-2 larvae of B. mori were subjected to chronical starvation for 72 h, the contents of triglyceride and glycogen in the fat body and the concentration of trehalose in the hemolymph were measured every 12 h, and the expression levels of BmFoxO, insulin receptor gene (InR) and protein kinase B gene (Akt) of insulin pathway and genes related to lipid metabolism were detected in the fat body by qPCR. A vector overexpressing BmFoxO was constructed and transfected into BmE cells, and the expression levels of genes related to glucose and lipid metabolism in BmE cells were detected by qPCR. 【Results】 The contents of glycogen and triglyceride in the fat body of the silkworm larvae continuously decreased within 72 h after starvation, and the concentration of trehalose in the hemolymph increased during 48 to 72 h after starvation. qPCR results revealed that the expression levels of genes of insulin pathway such as BmFoxO, InR and Akt and those linked to lipid metabolism enhanced remarkably during starvation stress, accelerating lipolysis. After overexpression of BmFoxO in BmE cells, the genes BmFoxO, InR and Akt showed a similar expression trend to that in B. mori larvae under starvation stress. 【Conclusion】 BmFoxO can regulate the glucose and lipid metabolism, and participate in the resistance to starvation in the silkworm. This study provides a basis for further studying the function of BmFoxO in the growth and metabolism in the silkworm.

【Aim】To identify fatty acid desaturase (FAD) genes in the whole genome of Hermetia illucens, and to investigate their spatiotemporal expression patterns and evolutionary pattern in representative dipteran insects. 【Methods】 The amino acid sequences of FAD genes of Drosophila melanogaster were downloaded from FlyBases and used as seed sequences to search for FAD genes in H. illucens and several other representative species of Diptera by the local Blastp program across the whole genome. The phylogenetic tree of the FAD genes across several dipteran species was constructed by a neighbor-joining method (NJ) with MEGA7. 0. The expression patterns of FAD genes in representative tissues and developmental stages were determined based on the transcriptome data of H. illucens and were further verified using RT-PCR. 【Results】 In this study, a total of 13 FAD genes in the whole genome of H. illucens were identified and annotated with general characteristics. The phylogenetic analysis revealed that gene duplication occurs in partial H. illucens FAD genes, such as HillFAD-10 and HillFAD-12, and HillFAD-9 and HillFAD-11. In contrast, we also found that partial FAD genes, such as HillFAD-5 and HillFAD-6, present a consistent evolutionary pattern in dipteran species, suggesting that they are relatively conserved and may play general roles in dipteran species. Transcriptome data analyses and RT-PCR results revealed that most FAD genes showed different expression patterns during the growth and development of H. illucens, e.g., HillFAD-2 and HillFAD-6 were expressed in embryo, larval, pupal and adult stages, HillFAD-3 were mainly expressed during the late embryo and the 4th instar larval stage while HillFAD-4 showed low expression levels in the whole developmental satge, suggesting that the FAD genes may play distinctive roles in the metamorphosis development process of H. illuences. 【Conclusion】 Our study not only identified the whole set of FAD genes in the whole genome of H. illucens, but also reconstructed their evolutionary pattern across dipteran species, enabling us to better understand the role of FAD in the ecological adaptation in Diptera. The expression patterns of FAD genes uncovered in this study also provide preliminary insights into the lipid metabolism in this important resource insect species.

【Aim】 To establish and optimize the RNAi system for alkaline ceramide (saCER) and neutral sphingomyelin (snSMase) genes of Chilo suppressalis by comparing the RNA interference efficiencies based on different methods and different target genes.【Methods】 Double-stranded specific RNA (dsRNA) of Drosophila daCER gene was introduced into Drosophila S2 cells by soaking in dsRNA-containing medium. Specific dsRNA of saCER and snSMase genes of C. suppressalis were synthesized in vitro and introduced into the 3rd instar larvae (micro-injection) and the 2nd instar larvae (fluorescent nanoparticle-mediated feeding) of C. suppressalis, respectively. The expression levels of these target genes were measured by qPCR for investigating the RNAi efficiency among different methods as well as different genes. 【Results】 The expression level of daCER gene decreased by about 84% by soaking Drosophila S2 cells in dsRNA-containing medium at a concentration of 15 ng/μL for 72 h. The RNAi efficiency of saCER gene was the highest (41%) at 60 h post injection into the 3rd instar larvae at the dsRNA concentration of 5 000 ng/μL, and that of snSMase gene was the highest (47%) at 48 h post injection at the dsRNA concentration of 2 500 ng/μL. The highest RNAi efficiencies of saCER and snSMase genes were obtained on the 7th day (32%) and the 8th day (52%)， respectively, after feeding the 2nd instar larvae with dsRNA (48 μg/d). For aCER gene in Drosophila S2 cells, the interference efficiency with soaking method was significantly higher than those with injection and feeding method of C. suppressalis. There was no significant difference in the RNAi efficiency of saCER and snSMase genes using the same introduction method, and between methods of micro-injection and fluorescent nanoparticle-mediated feeding for the same gene (saCER or snSMase) of C. suppressalis. 【Conclusion】 The aCER and nSMase genes are sensitive to RNAi by introducing dsRNA both in vivo and in vitro. The protocols of RNAi via micro-injection and fluorescent nanoparticle-mediated feeding developed and optimized in this study are feasible for the basic research of enzyme genes of the sphingolipid metabolism. The RNAi efficiencies of aCER gene in C. suppressalis larvae using injection and feeding methods were significantly lower than that in Drosophila S2 cells using soaking method, further confirming that the interference efficiency of dsRNA into the C. suppressalis cells is greatly reduced due to the rapid degradation of dsRNA by RNase in hemolymph and the barrier of midgut pericardial membrane.

【Aim】 The purpose of this study is to investigate the infection process by Beauveria bassiana in the integument and fat body of Antheraea pernyi pupae so as to further clarify the pathogenesis in A. pernyi pupae infected by B. bassiana. 【Methods】 The morphological changes in the integument and fat body of A. pernyi pupae infected by B. bassiana were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. 【Results】 SEM observation indicated that the infection of B. bassiana in A. pernyi pupae mainly occurred at valves, bristles root and the intersegmental membrane between head and thorax. Besides, conidia penetrated into the body directly from the thick and hard wall of the body. TEM observation indicated that in the fat body, organelles except mitochondria were first infected, and then the fat droplets were eroded. The infected fat droplets became shallow, their surface had many holes and became deformed, and the fat droplets were divided into small fat droplets, indicating that they were completely eroded. When pupae were rigid, fat cells were completely destroyed, leaving only the blastospores and hyphae. 【Conclusion】 The integument and fat body of A. pernyi pupae infected by B. bassiana have obvious histopathological changes.

【Aim】 Lifespan and stress resistance are two important factors that influence the commercial production of entomopathogenic nematodes (EPNs). This study aims to identify the function of DAF-16 gene in DZ0503CMFT (DZ), the type strain of Heterorhabditidoides chongmingensis, and to clarify the roles of the gene in the lifespan and stress resistance of DZ nematodes. 【Methods】 DAF-16, a major transcription factor of IIS pathway, was selected from digital gene expression profile (DGE) according to differential development of two monoxenic DZ nematodes associated with different symbiotic bacterial strains of Serratia, i.e., a non-native bacterial strain DR186 (186) and a native strain S1 of S. nematodiphila. The specific fragment of daf-16 was selected as the interference fragment by homology analysis, L4440 plasmid was used to construct the dsRNA expression vector of the interference fragment, and then the dsRNA expression vector of the interference fragment was transformed into Escherichia coli HT115 (DE3). daf-16 dsRNA was introduced into DZ nematode by feeding with the constructed engineering bacterium, and the effect of RNAi was detected by real-time quantitative PCR. The changes of the lifespan, spans of four physiological stages, stress resistance (heat stress and oxidative stress) and phenotype (body length) and reproduction characters (the number of eggs laid in 48 h, egg hatching rate and proportion of females) of DZ nematodes after daf-16 RNAi were observed and recorded. 【Results】 daf-16 (GenBank accession no.: MH101641) has a full-length cDNA of 2 164 bp with an open reading frame (ORF) of 1 353 bp in length, encoding 450 amino acids. After daf-16 RNAi in DZ nematodes, the expression level of daf-16 was significantly repressed with an average reduction of 49.05% as compared with that of the control group (L4440 group) in qPCR assay. The average lifespan of DZ nematodes of the daf-16 RNAi group (14.96 d) was reduced as compared with that of the L4440 group (17.60 d), with a decrease of 15.00%. Spans of the reproductive stage and fast body movement stage of DZ nematodes of the daf-16 RNAi group were shorter than those of the L4440 group, whereas the spans of the fast pharyngeal pumping stage and pharyngeal pumping stage of DZ nematodes of the daf-16 RNAi group were longer than those of the L4440 group. The survival rate of DZ nematodes of the daf-16 RNAi group was significantly lower than that of the L4440 group when the nematodes were exposed to heat stress (37℃) and oxidative stress (10 mmol/L paraquat solution) for 7 d. There was no significant difference in the number of eggs laid in 48 h, egg hatching rate, proportion of females and body length between the daf-16 RNAi group and the control group. 【Conclusion】 The biological functions of daf-16 in DZ nematode were identified by RNAi, which regulates the lifespan and stress resistance of DZ nematode.

【Aim】 In view of the scarcity of botanical pesticide products for controlling thrips pests, the aim of this study is to evaluate the insecticidal activity of plant materials against thrips so as to lay a foundation for the development of botanical pesticide products. 【Methods】 The fumigation activities of 126 plant essential oils or main components of essential oils against Anaphothrips obscurus were evaluated by triangle bottle fumigation method. 【Results】 Ten plant essential oils or main components of essential oils showed high fumigation activity against both the 2nd instar nymphs and adults of A. obscurus, with the fumigation toxicity in the descending order as follows: wintergreen oil, oregano oil, cinnamon oil, thyme oil, citral, sassafras oil, perilla leaf oil, garlic oil, dipentene, and terpineol. The LC₅₀ values of the wintergreen oil against the 2nd instar nymphs and adults were 0.97 and 2.56 μL/L, respectively, while those of the oregano oil were 1.47 and 3.27 μL/L, respectively. At the LC₉₅ dose, the LT₅₀ values of the 10 plant essential oils against A. obscurus adults in the ascending order were sassafras oil, citral, terpineol, dipentene, oregano oil, wintergreen oil, thyme oil, cinnamon oil, perilla leaf oil and garlic oil. The LT₅₀ value of the sassafras oil against A. obscurus adults was 17.31 min, with the fastest fumigation effect. 【Conclusion】 The wintergreen oil, oregano oil and sassafras oil exhibit high fumigation activity against A. obscurus, have the application potential and are worth further research.

【Aim】 This study aims to assess the toxicity and hazard of six neonicotinoid insecticides to Osmia excavata. 【Methods】 The acute oral and contact toxicities of six neonicotinoid insecticides, i.e., acetamiprid, thiamethoxam, sulfoxaflor, imidacloprid, clothianidin and dinotefuran, to the female adults of O. excavata at 24 h and 48 h after treatment were measured by feeding application and topical application methods, respectively. The risk of insecticides to O. excavata was assessed based on the hazard quotient (HQ) values of the ecological risk of insecticides to bees. 【Results】 In oral toxicity assay, sulfoxaflor showed the highest toxicity to the female adults of O. excavata while thiamethoxam showed the lowest toxicity. In contact toxicity assay, clothianidin showed the highest toxicity to the female adults of O. excavata, while sulfoxaflor showed the lowest toxicity. Acetamiprid, thiamethoxam and imidacloprid presented medium risk to O. excavata, while clothianidin presented high risk. And sulfoxaflor and dinotefuran presented medium risk to O. excavata by contact but high risk by oral exposure. 【Conclusion】 The six neonicotinoid insecticides assessed in this study present high risk to the female adults of O. excavata. It should be cautious to use acetamiprid, thiamethoxam and imidacloprid during florescence, and the use of clothianidin, sulfoxaflor and dinotefuran should be avoided in the orchard.

【Aim】 Organisms (including migratory insects) on the earth are constantly affected by the geomagnetic field (GMF). The migratory insects can have a long distance migration, and there is a perceptible difference in the GMF intensity between the emigration and immigration regions, which affects the population fitness of migratory insects. This study was carried out to clarify the magnetobiological effect on migratory insect populations so to help predict the occurrence of migratory insect pests. 【Methods】 The GMF intensities of the spring emigration (Guangzhou city, GMF 45 μT) and immigration (Nanjing city, GMF 50 μT) regions of the brown planthopper, Nilaparvata lugens, a migratory pest, were simulated by the DC-type helmholtz coils, respectively, and the changes in the growth, development and reproduction of N. lugens in response to the GMF intensity change between the emigration and immigration regions were investigated. 【Results】 The results showed that in the immigration region (GMF 50 μT), the egg duration of N. lugens was slightly shortened (0.50%), the egg hatching rate was significantly enhanced (6.11%), the developmental duration of female and male nymphs was lengthened by 5.26% and 2.37%, respectively, the body weight of the newly emerged female and male adults was increased by 0.66% and 9.56%, respectively, and the developmental duration of female and male adults was shortened by 35.34% and 26.15%, respectively, as compared with those in the emigration region (GMF 45 μT). Moreover, the fecundity of female adults was significantly enhanced (30.13%) and the relative transcription level of Vg was significantly enhanced (259.25%). Furthermore, compared with the GMF intensity 45 μT, the GMF intensity 50 μT significantly decreased the egg duration (2.52%) and significantly increased the egg hatching rate (10.83%) of the F₁ generation of N. lugens. 【Conclusion】 The results suggest that the GMF intensity of the region where N. lugens is located after northward migration in spring is positive for its migration to enhance the population fitness, further advantageous for the population occurrence and increasing the risk of population outbreak and damage in the immigration regions in spring.

【Aim】 To reveal the biological characteristics of the red morph of the pea aphid, Acyrthosiphon pisum after feeding on Medicago staiva seedlings cultivated under different CO₂ concentrations, and to verify the population succession of this insect under elevated CO₂ concentration. 【Methods】 Red pea aphids were reared on M. staiva seedlings under three CO₂ concentrations ［380 (CK), 550 and 750 μL/L］ in CO₂ gradient chamber for six consecutive generations, and the growth parameters, reproductive parameters and population life parameters for each generation were observed and analyzed. 【Results】 The elevated CO₂ concentrations presented significant effects on the biological parameters of red pea aphids (P<0.05). With the increase of CO₂ concentration and the number of generations of the pea aphid, the developmental duration of red pea aphids was significantly prolonged, whereas the adult longevity was significantly shortened and the mean fecundity significantly decreased (P<0.05). Moreover, with the increase of CO₂ concentration, the net reproductive rate (R₀), intrinsic increase rate (r_m) and finite increase rate (λ)  of the same generation were all decreased, while the generation time (T) was shortened and then extended. The maximum net reproductive rate, intrinsic increase rate and finite increase rate in the pea aphid reared on M. staiva seedlings under 750 μL/L CO₂ concentration were decreased by 7.71%, 34.57% and 84.39% respectively, as compared with the control. 【Conclusion】 The elevated atmospheric CO₂ concentration presents negative effects on the population of the red morph of the pea aphid, which are more significant with the increase of generations.

【Aim】 To clarify the effects of Lygus pratensis infestation on the nutrients and protective enzymes of host plants. 【Methods】 The contents of chlorophyll, soluble sugar, amino acids, and protective enzyme activities in the leaves of 10 host plants (six preference hosts with the preference in the descending order as Chenopodium glaucum, Portulaca oleracea, Amaranthus retroflexus, Medicago sativa, Kochia prostrate and Gossypium hirsutum, and four non-preference hosts including Suaeda glauca, Medicago lupulina, Convolvulus arvensis and Lepidium latifolium) infested by L. pratensis were determined, respectively, using biochemical methods. 【Results】 After the host plants were infested by L. pratensis, decreased chlorophyll contents were recorded in leaves of all the tested hosts, with the lowest decrease rate in A. retroflexus (2.6%) and the highest in M. sativa (26.21%). The soluble sugar contents varied a lot after L. pratensis infestation. The soluble sugar content in infested leaves of K. prostrata was significantly declined by 24.05%, while significantly increased by 68.92% in infested leaves of C. glaucum. Except that the free proline content in leaves of A. retroflexus was decreased by 38.87%, those in leaves of all the other host plants were stimulated by L. pratensis infestation. The protein contents in leaves of all the host plants were all decreased after L. pratensis infestation, with the lowest decline by 2.96% in A. reflexus as compared to the control (uninjured plants). The POD activities in leaves of different host plants increased after L. pratensis infestation, with the highest increase rate (74.23%) in P. oleracea. After L. pratensis infestation, the CAT activities in leaves of host plants fluctuated a lot. The CAT activities in infested leaves of C. glaucum, M. sativa and C. arvensis increased by 45.07%, 30.95% and 22.47%, respectively, as compared to the control. However, significantly decreased CAT activities were observed in infested leaves of P. oleracea and M. lupulina. Except that the SOD activities in leaves of A. lividus and M. lupulina infested by L. pratensis decreased, the SOD activities in leaves of all the other host plants were increased but showed no significant difference. 【Conclusion】 After host plants are injured by L. pratensis, the changes in the contents of chlorophyll and free proline in leaves of host plants are well correlated with the preference of L. pratensis to these hosts, while the contents of soluble sugar and protein and the protective enzyme activity have no correlation with the host preference of L. pratensis.

【Aim】 Athetis lepigone outbreaks recently and seriously damages summer maize (Zea mays) seedlings in China. This study aims to determine the biological and nutritional effects of different maize cultivars on A. lepigone larvae and to understand the relationship between the occurrence of this pest and maize cultivars. 【Methods】 The 3rd, 4th and 5th instar larvae of A. lepigone were fed on three regular maize cultivars(Ludan 9032, Xianyu 335 and Zhengdan 958)and one sweet maize (Chaotian 6), and their fresh weight, dry weight, survival rate, relative consumption rate (RCR), relative growth rate (RGR), approximate digestibility (AD), efficiency of conversion of digested food (ECD) and efficiency of conversion of ingested food (ECI) were determined, and the relationships between these indexes and the contents of nutrients, wax and secondary metabolites in maize seedlings were analyzed. 【Results】 The biological and nutrition indexes differed among different instar larvae of A. lepigone fed on four maize cultivars, and the contents of nutrients, wax and secondary metabolites differed among the four maize cultivars. The 3rd instar larvae fed on Ludan 9032 and Chaotian 6 had higher RCR, RGR and AD than those fed on Zhengdan 958 and Xianyu 335. The survival rate, fresh weight, dry weight, RCR and ECD of the 3rd instar larvae were significantly positively correlated to the soluble sugar content in maize seedlings, the RGR positively correlated to the protein and amino acid contents, the survival rate and RCR negatively correlated to the total phenol content, and the ECD negatively correlated to the tannin content. The 4th instar larvae fed on Xianyu 335, Chaotian 6 and Zhengdan 958 had the lowest fresh weight and dry weight, the highest AD and the highest ECI, respectively. The fresh weight, dry weight, RCR and RGR of the 4th instar larvae were significantly negatively correlated to the total phenol content in maize seedlings. The 5th instar larvae fed on Ludan 9032 and Xianyu 335 had higher fresh weight, dry weight and ECD, while those fed on Zhengdan 958 and Chaotian 6 had higher RCR and AD. The 5th instar larvae fed on Xianyu 335 had the highest ECI. The RGR of the 5th larvae was significantly positively correlated to the protein and amino acid contents in maize seedlings. 【Conclusion】 The adaptability of A. lepigone larvae to maize improves with the larval instar, and is positively correlated to the contents of soluble sugars, proteins and amino acids in maize seedlings, and negatively correlated to the total phenol and tannin contents.

【Aim】 In order to clarify the sperm morphology of Cicadidae and their significance in insect taxonomy and phylogeny, the sperm ultrastructures of Meimuna mongolica, Cryptotympana atrata, Pycna repanda, and Tettigetta sp. were compared in this study. 【Methods】 The morphological characteristics of sperm of four species of Cicadidae were observed using light and transmission electron microscopies, respectively. 【Results】 The sperm morphologies of M. mongolica, C. atrata, P. repanda and Tettigetta sp. are similar, but the sperm length is significantly different within and between species. Spemotozoa of all these investigated species show polymegaly. Based on the length of spermatozoa, spermatozoa in P. repanda can be divided into three types, i.e., long spermatozoa, medium spermatozoa, and short spermatozoa. The spermatozoa of M. mongolica, C. atrata and Tettigetta sp. are only divided into two types, i.e., long spermatozoa and short spermatozoa. The sperm ultrastructures of these four species are similar, i.e., the head region contains the acrosome and the nucleus, the neck region is composed of a centriole and a centriolar adjunct, the tail region generally consists of an axoneme and a pair of mitochondrial derivatives, and the axoneme has a 9+9+2 arrangement of microtubules (9 accessory microtubules, 9 doublet microtubules, and 2 central microtubules). However, some differences were revealed in sperm ultrastructure among different species. Some spermatozoa in the three species of the subfamily Cicadinae possess multiple mitochondrial derivatives. An electron-dense deltoid region exists in the sperm tail of P. repanda, which has never been found in other cicadas. The structure of the centriolar adjunct of spermatozoa is significantly distinct among different subfamilies within the Cicadidae. The centriolar adjunct exhibits a lamellar structure in Cicadettinae, but has a sheath structure in Cicadinae. 【Conclusion】 Compared with the spermatozoa in Membracoidea and Cercopoidea within Cicadomorpha, only the spermatozoa in Cicadidae show polymegaly, which is a synapomorphy of this family. Whether the occurrence of multiple mitochondrial derivatives in the tail of flagellum is ubiquitous within the subfamily Cicadinae still needs further study. The differences in sperm morphology in different groups of Cicadidae provide significant information for the taxonomy of Cicadidae and the phylogenetic analysis of Cicadomorpha.