【Aim】 This study aims to investigate the effects of amino acid substitutions of topoisomerase I (Top I) on its DNA relaxation activity in the beet armyworm,  Spodoptera exigua (Lepidoptera: Noctuidae). 【Methods】 The NH₂ -terminally truncated  Top I (Top70) from S. exigua was amplified and cloned into the BamH I-Sal I sites of the pGEX-4T-1. Mutant constructs substituted with V420I, L530P, A653T and S729T (numbered according to human Top I) were obtained by PCR-based site-directed mutagenesis using the wild construct pGEX-4T-1-Top70 as the template separately. The wild and mutated constructs were expressed in Escherichia coli strain BL21 (DE3). The GST fusion protein was purified using GSTrap 4B, and the DNA relaxation activity of the purified protein was detected with pBR322 as substrate. 【Results】 The wild and mutated pGEX-4T-1-Top70 expression vector was successfully constructed, and the cell line stably expressing Top70 was established. A 96.0 kDa specific protein band appeared when the expressed protein was analyzed with SDS-PAGE. Compared to the wild Top I, the mutated Top I with amino acid substitutions at positions V420I, L530P and A653T had significantly decreased DNA relaxation toward pBR322. However, the S729T amino acid substitution showed no significant impact on the catalytic efficiency of Top I. 【Conclusion】 These results suggest that V420T, L530P and A653T amino acid mutations in S. exigua remarkably decline the affinity of Top I to pBR322, providing important basic information for further investigating the sensitivity of Top I to the camptothecin and its analogous.

【Aim】 This study aims to investigate whether DNA methylation and histone acetylation are involved in the regulation of immune responses in the silkworm,Bombyx mori. 【Methods】 We performed the phylogenetic analysis of DNA methyltransferase 1 (DNMT1), histone deacetylase (HDAC) I-1, I-2 and histone acetylase 1 (HAT1) from B. mori and other species. We also profiled their mRNA levels after bacterial ( Pseudomonas aeruginosa or  Staphylococcus aureus) infection in the fat body of day-3 5th instar larvae. We then investigated the effects of DNMT inhibitor, HDAC inhibitor and HAT inhibitor on the survival of day-2 5th instar larvae after bacterial infection. 【Results】 Phylogenetic analysis showed that BmDNMT1 is particular and separated from the homologs of other insect taxa. BmHDACs and BmHAT1 are evolutionarily conserved. BmDNMT1, BmHDACs and BmHAT 1 in the fat body had higher expression levels after bacterial challenge. However, no obvious effects of DNMT, HDAC and HAT inhibitors on the survival of silkworm larvae after bacterial infection were observed. 【Conclusion】 The expression levels of BmDNMT1, BmHDACs and BmHAT1 in the fat body of B. mori larvae are up-regulated after infection of P. aeruginosa or S. aureus, suggesting that DNA methylation and histone acetylation/deacetylation might be involved in the regulation of immune responses in the silkworm.

【Aim】 A blood meal is essential for the anautogenous mosquito to complete each gonotrophic cycle. The hydrolysis of blood proteins by midgut proteases results in a massive release of free heme, a known prooxidant molecule. The blood-sucking mosquitoes must strictly regulate heme homeostasis. An important component of this control is heme oxygenase (HO). The existing research results show that the heme-degradation pathway is likely to be different in different insect orders. Our study aims to clone HO-1 gene from  Anopheles sinensis, analyze its expression post blood feeding to provide the foundation for further research of the molecular mechanism of heme homeostasis in An. sinensis. 【Methods】 A transcriptome database for An. sinensis was mined through bioinformatic analysis. Gene expression levels were analyzed in the midgut and other body tissues except midgut (carcass) and at different time post blood feeding using real-time PCR. Meanwhile, the concentrations of heme at different time post blood feeding were measured. 【Results】A HO-1 gene was identified, and named as AsHO-1, with the GenBank accession number of KP994552. AsHO-1 contains a 729 bp open reading frame encoding 242 amino acid residues. Expression analysis showed that AsHO-1 was simultaneously expressed in the midgut and carcass of An. sinensis and the expression level of AsHO-1 in carcass was markedly higher than that in the midgut. AsHO-1 mRNA levels remained elevated at 6-12 h after glucose feeding with a maximum 4.2fold increase, while the expression level significantly increased at 12-24 h post blood feeding with a maximum 11.67-fold increase. The heme level increased significantly at 3 h post blood feeding, peaked at 6 h, and then decreased at 18 h. 【Conclusion】 These findings suggest that AsHO-1 can be induced by blood feeding, and may be involved in the regulation of heme homeostasis, although further researches need to be performed to confirm this speculation. Furthermore, AsHO-1 is also highly expressed at larval stage and in body tissues except midgut, suggesting that AsHO-1 might be involved in multiple physiological processes of An. sinensis.

【Aim】 This study aims to analyze the genetic characteristics of sacbrooe virus (SBV) isolated from Apis cerana cerana in Chongqing, southwestern China (AcSBV-S.Chn-CQ). 【Methods】 The polyprotein gene of SBV was amplified by RT-PCR from samples of A. c. cerana  larvae infected with SBV, which originated from 23 districts or counties in Chongqing, sequenced and analyzed. Phylogenetic trees were constructed using neighbor-joining method based on SBV genome, and the genomic region SB11-SB12. RDP3 was used to detect the genetic recombination. 【Results】 AcSBV-S.Chn-CQ showed high homologies with other SBV isolates from  A. c. cerana in South China (AcSBV-S.Chn), the SBV infecting  A. cerana and A. mellifera in North Vietnam (AcSBV-N.Vie and AmSBV-N.Vie) and the SBV infecting A. cerana in South Korea (AcSBV-S.Kor). AcSBV-S.Chn-CQ has a consecutive 51-nucleotide deletion along the structural protein-coding region and an inconsecutive 3-nucleotide deletion along the nonstructural protein-coding region, and its nucleotide deletion is identical to those of AcSBV-N.Vie, AmSBV-N.Vie and AcSBV-S.Kor. AcSBV-S.Chn-CQ, AcSBV-S.Chn-FZ, AcSBV-N.Vie, AmSBV-N.Vie and AcSBV-S.Kor formed a subtype within the Asian genotype, and recombination events were detected in the isolates within this subtype. 【Conclusion】 AcSBV-S.Chn-CQ, SBV-N.Vie and AcSBV-S.Kor may share a common origin.

【Aim】 This study aims to clarify the influence of endosymbiont Wolbachia on the reproductive fitness and adult longevity of Nasonia vitripennis. 【Methods】 Different concentrations of rifampicin (a kind of antibiotics) were used to feed N. vitripennis adults for removing Wolbachia in their bodies to assess the effect of Wolbachia on the reproductive fitness and adult longevity of N.vitripennis in the next ten consecutive generations. 【Results】 The results showed that the low rifampicin concentrations (0.1-0.5 mg/mL) had lower toxicity, while high rifampicin concentrations (0.7-10.0 mg/mL) had higher toxicity to N. vitripennis, but Wolbachia could be removed by all the concentrations of rifampicin. The number of offspring as well as sex ratio (female to all offspring ratio) of N. vitripennis decreased significantly after removing Wolbachia, while there was no significant difference in adult longevity between the Wolbachia infected and uninfected individuals. 【Conclusion】 All the different concentrations of rifampicin can remove Wolbachia from N. vitripennis, but the efficiency varies. Wolbachia  has distinct effects on the number of offspring and sex ratio of N. vitripennis, while has no evident influence on its adult longevity.

【Aim】 This study aims to explore the olfactory learning capability of the male adults of the oriental fruit fly,  Bactrocera dorsalis (Hendel). 【Methods】 A classical olfactory conditioning procedure was adopted. The 14-17 day-old male adults of B. dorsalis were individually trained to associate odor with food in the laboratory, i.e., exposed to peppermint odor paired with 10% sucrose solution for appetitive conditioning and methyl eugenol (ME) paired with saturated salt solution for aversive conditioning. The change of the proboscis extension reflex was used as the criterion for conditioning. 【Results】 The proportion of proboscis extension reflex of male adults of B. dorsalis increased from 0% to 68% after appetitive conditioning, and decreased from 100% to 36.54% after aversive conditioning. And its variation was generated by a temporal relation between odor conditioned stimulus (CS) and food unconditioned stimulus (US) (paired). 【Conclusion】 These results indicate that male adults of B. dorsalis have a strong capacity to form an olfactory memory as a result of classical conditioning, while the contiguity of CS and US is a necessary condition of learning.

【Aim】 The camellia weevil,  Curculio chinensis Chevrolat, is an important pest attacking fruits of the oil tea  Camellia, an endemic genus to China, and causes tremendous fruit drop of its host plants. To reveal the oviposition strategy of  C. chinensis, we explored the relationships between oviposition activity of C.chinensis  and the traits of its host fruit. 【Methods】 During the most active oviposition season, 960 fruits of  C. meiocarpa  were collected randomly from an oil tea ( Camellia meiocarpa) farm. The number of punctures and clutch size of C. chinensis, as well as the weight, length and diameter of each fruit were measured, and the difference of fruit size among oviposition-punctured fruits, feeding-punctured fruits and non-damaged fruits was analyzed through one-way ANOVA (LSD), and the effect of fruit traits on feeding and oviposition activity was analyzed through linear regression model. A choice test of the pest on fruits size was carried out, and the difference of fruit size between selected and non-selected fruits was analyzed by paired-samples t test. 【Results】 Oviposition-punctured fruits of C. meiocarpa were significantly larger than feeding-punctured fruits, while the latters were significantly larger than non-damaged fruits in terms of weight, length, diameter, and volume (P＜0.01). The number of punctures, clutch size and weevil parasitism rate were positively correlated with fruit size (P＜0.01), suggesting that parental weevils prefer larger fruits to feed and oviposite. The female adults of C. chinensis showed obvious preference to larger fruits when the difference of fruit size between the two fruits tested was significant, and heavily damaged fruits were significantly larger than lightly damaged fruits in terms of length and diameter after infection by female adults of C. chinensis for 12 h. Independent of host fruit traits, C. chinensis laid one egg in each puncture hole. 【Conclusion】 C. chinensis adults prefer larger fruits to feed, which supports the optimal foraging theory. C. chinensis adults also prefer larger fruits to oviposite. The small clutch size would reduce intraspecific competition C. chinensis between offsprings and increase the probability of larval development, and thus they would be more likely to successfully exit from host fruits. We infer that the single egg laying behavior in C. chinensis is a riskspreading strategy, an adaptation toward limited food resource.

【Aim】 This study aims to determine the size variation of adults and the overwintering larvae of the Japanese pine sawyer, Monochamus alternatus, and to explore the relationship of the body size of adults and the body weight of overwintering larvae of this species. 【Methods】 Field trapping of M. alternatus adults was carried out from 1st May to 31st October in 2014 in forests of Changdong, Fuyang County in Zhejiang Province, and the body length and width of adults trapped were measured with micrometer to determine the size variation. Overwintering larvae were collected also in Changdong forests in March 2014 and then taken back to the laboratory and reared with artificial diet until adult emergence, during which the weight and width of head capsule of larvae, pupal weight and adult size were recorded to analyze the relationship between the size variations of adults and the overwintering larvae. 【Results】 Trapped M. alternatus adults varied in body size. The body length and width of female adults averaged 20.59±0.19 and 6.59±0.06 mm, respectively, while those of male adults averaged 19.90±0.26 and 6.44±0.08 mm, respectively. Female adults were significantly longer than males. Furthermore, body length was significantly correlated with body width for both female and male adults. The investigation of overwintering larvae showed that M. alternatus larvae overwinter mainly at the 4th and 5th instar by measuring the width of head capsule, which ranged from 2.20 to 4.24 mm, and larval body size also varied, ranging from 71.6 to 858.0 mg with the average of 304.2 mg among which the 5th instar overwintering larvae was significantly heavier than the 4th instar overwintering larvae. Further analysis showed that the size of pupae and adults was determined by the size of overwintering larvae. Regression analysis showed that the pupal weight, adult weight, adult length, and adult width were significantly correlated with the overwintering larval weight, respectively. Pupae and adults reared from the 4th instar overwintering larvae were significantly lighter than those reared from the 5th instar overwintering larvae. 【Conclusion】 The body size of M. alternatus adults is quite varied, which is related to the size variation of overwintering larvae. Variation in larval size may be attributed to the long flight period of adults. Oviposition lasts the whole flight period, causing the difference in larval development time, and this difference as well as nutrition difference in different parts of host pine trees results in the variation in larval body size until overwintering.

【Aim】 This study aims to investigate intra-guild predation in aphidophagous predaceous insects and their control effects of the cotton aphid, Aphis gossypii, in Xinjiang, West China. 【Methods】 We conducted experiments in greenhouse to examine intraguild predation between the seven-spotted ladybird beetle, Coccinella septempunctata, and the green lacewing, Chrysopa pallens,by pairing them at different life stages on potted cotton seedlings in the absence of the prey aphid A. gossypii. In addition, we manipulated the two predators at larval and adult stages as pairing treatments to investigate their effects on A. gossypii density on potted cotton seedlings. 【Results】 In the absence of aphids, intraguild predation between two predators on cotton plants for 24 h showed the following results. In pairing treatments of two predators at comparable life stages, no intraguild predation occurred at adult stage; Ch. pallens survived more than C. septempunctata at the 1st larval instar; but C. septempunctata survived more than Ch. pallens at the last larval instars. In pairing treatments involved with eggs, the eggs were preyed on in all pairings except that C. septempunctata eggs were not preyed on by Ch. pallens adults. In pairing treatments including pupae, the pupae were not preyed on except that C. septempunctata pupae were preyed on by the last instar larvae ofCh. pallens. In pairing treatments between larvae and adults, C. septempunctata adults preyed on the 1st instar larvae of Ch. pallens, but not on the last instar larvae, and no intraguild predation occurred between Ch. pallens adults and the 1st instar or 4th instar larvae of C. septempunctata. In pairing treatments between different instar larvae, the last instar larvae of Ch. pallens preyed on the 1st instar larvae of C. septempunctata  but its 1st instar larvae was preyed on by the 4th instar larvae of C. septempunctata. Experiments to examine effects on A. gossypii density of the two predator pairings showed that whereas two predator larvae each alone decreased A. gossypii density, pairing treatments between Ch. pallens larvae and either C. septempunctata larvae or adults increased the aphid density, but pairing treatments between Ch. pallens  adults and either C. septempunctata larvae or adults caused the decrease of aphid density. 【Conclusion】 The results suggest that intraguild predation occurs between Ch. pallens and C. septempunctata, but their combined effects on aphid density may depend on Ch. pallens life stages involved, decreasing aphid density at the adult stage but increasing it at the larval stage.

【Aim】 Galeruca daurica (Joannis)is a new pest causing damages seriously in Inner Mongolia grasslands in recent years. This study aims to investigate the genetic differentiation and gene flow among different geographic populations of G. daurica in Inner Mongolia. 【Methods】 By using five microsatellite primer pairs, we analyzed the genetic diversity, gene flow and genetic differentiation among eight populations of G. daurica. 【Results】 The number of alleles and effective number of alleles per locus ranged from 10 to 18 and 9.2796 to 16.0388, respectively. The polymorphic information content per locus ranged from 0.6760 to 0.8985 and the expected heterozygosity ranged from 0.3430 to 0.5284, demonstrating the high degree of polymorphism. Moreover, the expected heterozygosity of the eight populations ranged from 0.2216 to 0.3701, with the average of 0.2680. The genetic differentiation index (F_ST) ranged from 0.1244 to 0.4116, with the average of 0.2521, and the gene flow (N_m) ranged from 0.3574 to 1.7596, with the average of 0.9622. Eight populations were clustered into three groups according to their genetic distances, and the genetic distance between populations showed a highly significant correlation with the geographical distance (r=0.4854, P=0.0180). 【Conclusion】 The G. daurica populations are characterized by low genetic diversity. The gene exchange seldom exits and high genetic differentiation occurs between different geographic populations. The lower migration ability of this leaf beetle and geographic obstacles might be the main reason for the low gene flow and high genetic differentiation.

Three new species of the genus Oedaleus Fieber, 1853 from Taiwan, China are described in this paper. Oedaleus xiai sp. nov. differs from all known species of the genus by the tegmina shorter, just reaching the end of hind femur. Oedaleus kaohsiungensis sp. nov. is similar to Oe. formosana (Shiraki, 1910), but differs from the latter by the hind femur with black band on inner side and hind tibia yellowish brown, not red. Oedaleus nantouensis sp. nov. is similar to Oe. formosana (Shiraki, 1910), but differs from the latter by eye larger, vertical diameter almost equal to subocular furrow and interspace of mesosternum wider, minimum width 1.8 times length. Oedaleus nantouensis sp. nov. is also allied to Oedaleus kaohsiungensis sp. nov., but differs from the latter by hind femur red on lower side and hind tibia red. A key to all 13 known species of the genus from China is provided. Type specimens are deposited in the National Museum of Natural Science, Taichung, Taiwan, China.

The Eurasian woodwasp, Sirex noctilio Fabricius is an important forestry quarantine pest in the world, which prefers to attack conifer. It is native to Eurasia and North Africa. However, over the last one hundred years, S. noctilio has been gradually introduced to New Zealand and Austria in Oceania, then to South American countries including Uruguay, Argentina, Brazil, and Chile and later to Canada, the US and South Africa. The woodwasp was first detected in Heilongjiang Province, in the northeast region of China in August, 2013, where it mainly attacked  Pinus sylvestris. A very strict mutualistic relationship exists between S. noctilio and the white rot fungus Amylostereum areolatum (Fr.) Boidin. S. noctilio’s terrible attacks on host tree are in fact the act of its distinctive oviposition: female insects drill 1-5 small holes in the host tree through the bark to the cambium, injecting phytotoxic venom together with the arthrospores of A. areolatum, and sometimes an egg, into the holes. Together, the three pathogenic factors, Sirex larvae, symbiotic fungus and phytotoxic venom, act to weaken or even kill the tree. Particular attention should be paid to this important forest invading pest to China on account of its potential economic and ecological importance to Chinese forest ecosystem. In this article we reviewed the current researches on the symbiotic relationship between the woodwasp S. noctilio and its fungal symbiont A. areolatum. A great number of research findings on this subject were compared and summarized, in which the trophobiosis between Sirex larvae and the fungus, the spread of the fungus by woodwasps, the population structure of the fungus and the collaborative damage effect of the Sirex venom and the fungus on host tree were discussed in details. We attempted to provide some reasonable suggestions for the future study and open new insight into the control on this pest effectively.

【Aim】 This study aims to clarify the side effects of clothianidin and its two mixtures to Apis mellifera ligustica and Trichogramma ostriniae. 【Methods】 The acute toxicity of clothianidin and its two mixtures to adult workers of A. mellifera ligustica and adult T. ostriniae was determined in the laboratory, and the safety of these insecticides was evaluated. 【Results】 Stomach toxicity tests performed in standardized conditions on adult bees showed that clothianidin insecticides had very high toxicity to the adult workers of A. mellifera ligustica, with the LC₅₀ values of 0.0200 (0.0143-0.0272) for 30% clothianidin SC, 0.0847 (0.0658-0.1157) for 30% pymetrozine·clothianidin SC and 0.1594 (0.1200-0.2056) mg a.i./L for 20% ethofenprox·clothianidin SC, respectively. The LC₅₀  values of 30% clothianidin SC, 30% pymetrozine·clothianidin SC and 20% ethofenprox·clothianidin SC against adult workers of A. mellifera ligustica at 48 h after topical application were 0.0155 (0.0114-0.0197), 0.0426 (0.0335-0.0539) and 0.1122 (0.0796-0.1385) μg a.i. per bee, respectively. All the tested insecticides showed high contact toxicity to adult workers of A. mellifera ligustica. Toxicity of test insecticides to adult T. ostriniae  determined by using dry film residue method under laboratory conditions showed that the LC₅₀  values (24 h) of 30% clothianidin SC, 30% pymetrozine·clothianidin SC and 20% ethofenprox·clothianidin SC against adult T. ostriniae were 0.0232 (0.0180-0.0295), 0.1050 (0.0940-0.1170) and 0.0059 (0.0054-0.0065) mg a.i./L, respectively. The results of safety evaluation showed that 30% clothianidin SC, 30% pymetrozine·clothianidin SC and 20% ethofenprox·clothianidin SC were ranked as very high risk to adult T. ostriniaewith the safety factors of 5.95×10^-4, 2.69×10^-3 and 9.50×10^-5, respectively. 【Conclusion】 Clothianidin and its two mixtures have high risk of acute toxicity to both A. mellifera ligustica and T. ostriniae, so the use of these insecticides should be evaluated carefully in integrated pest management (IPM) programs.