【Aim】 Low temperature is one of the key factors affecting the growth, development and survival of insects. In order to clarify the cold hardiness of Bryodemella tuberculatum dilutum eggs and its mechanisms, we investigated the relationship between supercooling capacity and the contents of water and biochemical substances related to cold resistance in eggs in the laboratory. 【Methods】 The supercooling points (SCPs) were measured by thermocouple method, and the contents of water, fat, amino acids, low molecular sugars and polyols were determined by oven-drying method, residue method, automatic amino acid analyzer and high performance liquid chromatograph (HPLC), respectively. 【Results】 Soil water contents significantly influenced the SCPs, and water and fat contents in the pre-diapause eggs (P<0.01). Water content in eggs increased from 45.12% to 55.25% and fat content (fresh weight) decreased from 10.39% to 9.39%, whereas the SCP rose from -30.11℃ to -25.69℃ with the increase of soil water content from 4% to 13%. The SCPs and the contents of water, fat, amino acids, low molecular sugars and polyols in eggs had extremely significant differences among different developmental stages (P<0.01). From 1 to 120 d after oviposition, the SCP decreased from -26.78℃ to -30.18℃, water content declined from 51.93% to 46.69%, whereas fat content increased from 9.99% (fresh weight) and 17.37% (dry weight) to 13.92% (fresh weight) and 25.29% (dry weight),respectively. The SCPs of diapause eggs were significantly lower than those of pre-diapause eggs. Seventeen amino acids were detected in eggs, five of which were significantly correlative with the SCPs (P<0.05). The SCPs declined with the increase of glycin and proline contents whereas increased with the increase of cystine, leucine and aspartic acid contents. With the egg development, the contents of trehalose, glycerol, myo-inositol and sorbitol increased, whereas the contents of glucose and fructose decreased. The contents of trehalose and glycerol were much higher than those of the other low molecular sugars and polyols in the developmental process of eggs. There were significant correlations between the SCPs and contents of six low molecular sugars and polyols, among which trehalose and glucose contents were the most correlative with the SCPs. The SCPs decreased with the increase of trehalose, glycerol, myo-inositol and sorbitol contents whereas increased with the increase of glucose and fructose contents. 【Conclusion】 In the developmental progress of B. tuberculatum dilutum eggs, the supercooling capacity is enhanced by the reduction of water content and the accumulation of cryoprotectants such as fat, glycin, praline, trehalose, glycerol, myo-inositol and sorbitol.

【Aim】 To clarify the physiological mechanism of the effect of elevated CO₂ concentration on invasive insect Frankliniella occidentalis and the local related species F. intonsa.【Methods】 The activities of three detoxifying enzymes (caboxylesterase, CarE; acetylcholinesterase, AchE; microsomal mixedfunction oxidases, MFO) and three protective enzymes (superoxide dismutase, SOD; catalase, CAT; peroxidase, POD) in F. occidentalis and F. intonsa adults bred under different atmospheric CO₂ concentrations (400 μL/L and 800 μL/L) in CO₂ artificial climate chambers were assayed and analyzed. 【Results】 The activities of CarE, AchE, MFO, CAT and POD in F. occidentalis adults increased as the CO₂ concentration rose. The CarE and MFO activities in F. occidentalis adults bred under 800 μL/L CO₂ increased by 24.78% and 16.05%, respectively, as compared with those bred under 400 μL/L CO₂. The activities of CarE, MFO and CAT in F. intonsa adults bred through three successive generations under the high CO2 concentration (800 μL/L) was significantly higher than those bred under the low CO2 concentration (400 μL/L) (P＜0.05). The activities of AchE and POD in adults of the two thrips bred under the two CO₂ concentrations were not significantly different (P＞0.05). The SOD activities in F. occidentalis and F. intonsa adults bred under 800 μL/L CO₂ were significantly lower than those in adults of both species bred under 400 μL/L CO₂ (P＜0.05), decreased by 65.22% and 42.20%, respectively. 【Conclusion】 Elevated CO₂ concentration is the main reason for the increase in activities of CarE, MFO and SOD, and the changes in activities of AchE, CAT and POD are mainly influenced by thrips species. F. occidentalis and F. intonsa may adapt to the high CO₂ concentration environment by altering the activities of detoxifying and protective enzymes.

【Aim】 To understand the action mechanisms of ultraviolet B (UV-B) radiation in successive generations on the change of protective enzyme activities in the grain aphid, Sitobion avenae (Fabricius) and to find the drive on insect evolution under the pressure of UV-B environment.【Methods】 In this study, we used 0.25 W/m² of UV-B to radiate each generation of S. avenae for 6 h, and then continuously reared the nymphs for 18 generations. We chose the 1st, 4th, 8th, 12th, 15th, 18th generations of wingless and parthenogenetic adults in both the treatment group and control group, and used spectrophotometry to measure the activities of three protective enzymes (superoxide dismutase, SOD; peroxidase, POD; catalase, CAT) in them. 【Results】 The activities of SOD, CAT and POD in the control groups of different generations had no significant difference (P>0.05), while those in the treatment groups of different generations had significant difference (P<0.05). With the increase of the generations under UV-B radiation , the SOD activity first rose and then declined, reaching the peak in the 15th generation. The POD activity showed a declining trend with the increase of the generations under UV-B radiation but kept higher than that in the control group, and only in the 1st and 4th generations were there significant differences in the POD activity between the treatment group and the control group. The CAT activity first fell and subsequently increased with the increase of the generations under UV-B radiation, and those in the 8th, 12th and 15th generations under UV-B radiation showed no significant difference with the control group (P<0.05), but the CAT activity in the 18th generation under UV-B radiation showed extremely significant difference with that of the control group (P<0.01). 【Conclusion】 When S. avenae is irradiated by UV-B for a short time, the activities of protective enzymes in the body rise to resist the damage of radicals. As UV-B radiation works longer, the POD activity tends to be stable, while the SOD and CAT activities are significantly higher than the normal level to protect against UV-B stress.  

【Aim】 The ghost moth, Thitarodes xiaojinensis (Lepidoptera: Hepialidae), is a host insect of Chinese caterpillar fungus (Ophiocordyceps sinensis). Living at high altitude area, T. xiaojinensis is well adapted to the cold environment, while fails to survive under room temperature (RT, 25-27℃). To elucidate the physiological mechanism of death under RT, the effects of heat stress (27℃) on the digestive enzymes and antioxidant system of larval T. xiaojinensis were investigated. 【Methods】 The 8th instar larvae of T. xiaojinensis were treated in two groups: the high temperature group maintained at 27℃ and the control group maintained at 16℃. At 24 h after treatment, the living state of larvae was observed, and midguts and hemolymph were obtained through dissection. The relative contents of malondialdehyde (MDA) in the hemolymph were measured. The mitochondria structures of the midgut cells were observed under transmission electron microscope (TEM). The activities of enzymes including the total proteases and glycosyl hydrolase in the midgut, superoxide dismutase enzyme (SOD), catalase (CAT), and peroxidase (POD) in the hemolymph were tested. 【Results】 The activities of the total protease and glycosyl hydrolase in both groups increased with the reaction temperature (16-37℃). Covariance analysis indicated that the enzyme activities of the high temperature group were significantly lower than that of the control group (P<0.01). However, both protease and glycosyl hydrolase activities in the heat treated larvae tested at 27℃ reaction temperature were not significantly different from that in the control larvae tested at 16℃ reaction temperature (P<0.05). The MDA content in the hemolymph increased significantly after heat stress, indicating that oxidative damage occurred. The TEM analysis of mitochondria showed that mitochondrial structure was damaged with cristae disarranged and mitochondrial membrane broken. Among the protective enzymes, only the POD activity increased significantly upon heat stress (P<0.05), while the SOD and CAT activities did not significantly change (P>0.05). 【Conclusion】 The change of digestive enzyme activities may not be the important factor for the intolerance of T. xiaojinensis larvae under RT. Oxidative damage is one of the most important causes of larval death of the moth under heat stress.

 【Aim】 The small brown planthopper Laodelphax striatellus (Fallén), an important rice pest insect, feeds on rice and causes the decrease of yield and quality. Especially the rice stripe virus transmitted by L. striatellus induces more serious loss of rice. The small brown plant hopper is widely distributed and adapts to various environments. This study aims to clarify the molecular adaption mechanisms of L. striatellus under temperature stress preliminarily. 【Methods】 A full-length cDNA encoding Hsp90 from L. striatellus was cloned using RT-PCR and RACE technique. Different bioinformatics methods were used to analyze the characteristics of Hsp90. The expression levels of the Hsp90 gene among different developmental stages and under different temperatures were detected by the real-time PCR. 【Results】 The complete cDNA of LsHsp90 deposited in GenBank accession no. KF660250 is 2 740 bp in length, which encodes a protein of 729 amino acids, with the theoretical isoelectric point of 5.0 and molecular weight of 83.7 kDa. The amino acid sequence contains five signature sequences of Hsp90 family and a C-terminal cytoplasmic character sequence (EEVD). The LsHsp90 carries a classic Hsp90 family structural signature. The phylogenic tree demonstrated that LsHsp90 has high homology with Hsp90 proteins from some other insect species. The real-time PCR analyses exhibited that the expression levels of LsHsp90 varied remarkably in different developmental stages. The mRNA level observed was the highest in the 4th instar nymphs of L. striatellus, the lowest in female adults, and showed significant differences between male and female adults (P=0.008). The LsHsp90 mRNA level of L. striatellus could be induced by heat and cold temperature stress. The highest LsHsp90 mRNA level was observed at 40℃ and -9℃, respectively. At 40℃, LsHsp90 mRNA level reached a peak at 0.5 h after treatment, and then decreased with treatment time. However, at -4℃, the peak of LsHsp90 mRNA level was observed at 1 h after treatment. 【Conclusion】 The LsHsp90 gene in L. striatellus responds to temperature stress, and it may play an important role in the adaption process of the pest to temperature stress.

【Aim】 In recent years, the pink borer, Sesamia inferens (Walker) has become one of the major pests of rice with its damage increasing. With the global warming, it is further dispersing northward. Heat shock protein 70 (HSP70) family is of great significance for the correct fold and transmission of proteins in organisms. HSP70 participates in growth and development of organisms as chaperones, and causes responses to external stimuli. Our study aims to understand the expression differences of HSC70 gene from S. inferens in different tissues, in different developmental stages and under low-temperature stress, and to explore the molecular mechanisms of environmental adaptability of S. inferens. 【Methods】 RT-PCR and RACE were used to clone the full-length cDNA of HSC70 gene from the 5th instar larvae of S. inferens. The genomic sequence was demonstrated by genomic validation and intron was analyzed by sequence analysis of cDNA. The expression patterns of HSC70 gene were investigated by real-time quantitative PCR. 【Results】 The complete cDNA sequence was obtained and named as Sihsc70 (GenBank accession no.: KJ639908), which is 2 160 bp in length, containing an opening reading frame (ORF) of 1 962 bp and encoding 653 amino acid residues with the predicted molecular weight of 71.6 kDa. Three conserved sequences of HSP70 family exist in its amino acid sequence. The cytoplasmic localization signal in C-terminus indicated that S. inferens HSC70 is a cytoplasmic heat shock protein. Analysis of genomic DNA sequence (GenBank accession no.: KJ639909) demonstrated that HSC70 gene contains 2 introns. The 1st intron, 685 bp in length, is located upstream of the coding region. The 2nd intron, 803 bp in length, is located in the coding region. The expression levels of Sihsc70 were not significantly different among different tissues of the 5th instar larva (P＞0.05), with the higher expression levels in midgut, hindgut and epidermis, and the lowest in salivary glands. Sihsc70 had the lowest expression level in female adults, and higher expression levels in eggs, 2nd and 5th instar larvae, which were 6.33-, 3.21- and 1.86-fold as high as that in female adults, respectively. Compared with the control group (27℃), low-temperature stress had no significant effect on the expression of Sihsc70 in the 5th instar larvae (P>0.05). 【Conclusion】 The results suggest that Sihsc70 has different expression levels in different developmental stages and different larval tissues, and low-temperature stress would not induce high expression of this gene.  

 【Aim】 Prophenoloxidase (PPO) is an important immune protein in insects, which is involved in insect humoral immunity and cellular immunity. In our study, the prokaryotic expression system was applied to express soluble recombinant PPO with activity on a large scale. The recombinant PPO was used to screen various phenoloxidase (PO) inhibitors so as to create novel insecticides targeted on the insect immune system. 【Methods】 Using the PPO gene cloned from the 5th instar larvae of the Asian corn borer, Ostrinia furnacalis (Guenée), the prokaryotic expression vector, pET-28b-PPO, was constructed, and the recombinant PPO protein was expressed in Escherichia coli. The fusion protein was purified from the supernatant of the lysis of E. coli cells with Ni-NAT affinity chromatography column, and identified with Western blotting. Enzymatic characteristics of phenoloxidase (PO) activated from the recombinant PPO with cetylpyridinium chloride (CPC) and the effects of metal ions, such as Mg²⁺, Cu²⁺ and Fe²⁺ on the secondary structure of the recombinant PPO were also assayed and analyzed. 【Results】 The recombinant PPO protein was expressed and purified. The suitable temperature for PO obtained through the activation of the recombinant PPO was 30℃, and the suitable pH was 7.2. The kinetic parameters calculated for substrate oxidation were V_max=140.8 U/mg·min and K_m=0.92 mmol/L for L-DOPA. The content of β-sheet in the recombinant PPO increased dramatically to 53.7%±4.6% when Fe²⁺ ions existed. However, the content of α-helix decreased significantly to 2.6%±1.2%（P<0.05）. The content of β-sheet in the recombinant PPO reduced clearly and the content of α-helix increased slowly when Mg²⁺ ions existed. The content of β-sheet in the recombinant PPO declined remarkably to 10.0%±1.6% when Cu²⁺ ions were present, but the content of α-helix increased significantly to 35.3%±6.9%. 【Conclusion】 The results suggest that the secondary structure of the recombinant PPO is affected notably by different metal ions.

【Aim】 To identify a novel galectin gene from the silkworm, Bombyx mori, analyze its sequence and structural characteristics, detect its expression after microbial challenge and measure the binding properties of the expressed recombinant protein with microbe and microbial surface polysaccharides. 【Methods】 We used TBlastN to identify a novel galectin gene (named BmGalectin-4) by searching the silkworm genome database, and analyzed its sequence and structural characteristics with bioinformatics tools. The expression of BmGalectin-4 in different tissues in larval silkworm after microbial challenge (inoculation of Pseudomonas aeruginosa, Staphylococcus aureus and Candidiasis albicans, respectively) was detected by RT-PCR. The recombinant protein was produced in Escherichia coli and purified by affinity chromatography. The binding property of BmGalectin-4 with bacteria and fungus was analyzed by ELISA. Western blot was used to detect its binding to polysaccharides. 【Results】 Sequence analysis showed that BmGalectin-4 is a tandem repeat galectin, containing two carbohydrate recognition domains. BmGalectin-4 was expressed in fat body, hemocytes and midgut tissues, and its expression level changed significantly after bacterial and fungal challenge. Purified recombinant BmGalectin-4 showed significant binding capacity to Gram-positive and Gram-negative bacteria and fungus. Its binding to microbial surface polysaccharides was highly specific. 【Conclusion】 BmGalectin-4 is a typical tandem repeat galectin and might be involved in the silkworm immune responses against microbial pathogens. This study provides the foundation for further functional study of the silkworm galectin.

【Aim】 The diamondback moth (DBM), Plutella xylostella (L.), is one of the most important pests of cruciferous plants in the world. Cyantraniliprole is a novel anthranilic diamide insecticide registered for the control of lepidopteran pests, but there is sparse information available regarding its effects on P. xylostella. Here, we studied the effects of cyantraniliprole on biological characteristics and the related enzyme activities of P. xylostella. 【Methods】 The leaf-dipping method was used to test the toxicity of cyantraniliprole to the 3rd instar larvae of P. xylostella, and the LC₂₀ and LC₅₀ values were determined. The 3rd instar larvae were transferred onto cabbage leaves soaked in LC₂₀ and LC₅₀ of cyantraniliprole solution ［20% lethal concentration (LC₂₀)=0.03 mg/L and 50% lethal concentration (LC₅₀)=0.08 mg/L］ and allowed to feed for 48 h, then the biological characteristics such as the pupal duration, pupation rate, adult emergence rate and so on were recorded, and the related enzyme activities were also measured. 【Results】 The results showed that the estimated LC₂₀ and LC₅₀ values of cyantraniliprole on the 3rd instar larvae in leaf dip bioassay were 0.03 mg/L and 0.08 mg/L, respectively. Cyantraniliprole at LC₂₀ and LC₅₀ concentrations (LC₂₀=0.03 mg/L, LC₅₀=0.08 mg/L) could extend the duration of the 4th instar and pupal stage, and reduce the pupal weight and fecundity of P. xylostella. In treated groups, the pupation rate (F=42.19; df=2,6; P<0.05) and adult emergence rate (F=13.15; df=2,6; P=0.006) were significantly lower than those in the control group, respectively. Cyantraniliprole exposure also significantly increased the activities of protective enzymes (CAT and POD) at 12 h after treatment, but caused no effect on the activities of detoxification enzymes (CarE: P=0.43; GST: P=0.54; ODM: P=0.25). In contrast, cyantraniliprole exposure increased the activities of detoxification enzymes at 48 h after treatment, but caused no effect on the activities of protective enzymes (CAT: P=0.58; POD: P=0.13). 【Conclusion】 The LC₂₀ and LC₅₀ concentrations of cyantraniliprole have negative effects on the growth and development of P. xylostella, which could reduce the population density of the next generation. Moreover, cyantraniliprole at these two concentrations could induce the activities of the related detoxifying enzymes of P. xylostella. This finding is of great significance in guiding the use of this insecticide in field and delaying the development of insecticide resistance.

【Aim】 Different plant growth regulators could either facilitate or inhibit herbivores’ oviposition behavior, development and foraging, thus affecting the relationship between insects and their host plants. By detecting the potential effects of the widely used plant growth regulator indo-3-acetic acid (IAA) on Bemisia tabaci (Gennadius) biotype B, we aim to find out environmentally-friendly methods to whitefly management and hope to rear better whiteflies as alternative host of parasitoids. 【Methods】 We sprayed IAA on tomato Solanum lycopersicum L. seedlings, and then measured the physiological indexes of tomato leaves and the influences of IAA on the survival, oviposition and detoxification enzyme activities of B. tabaci adults. 【Results】 After application of IAA, the water content, leaf area, polyphenol oxidase (PPO) activity and chlorophyll concentration in tomato leaves increased, the peroxidase (POD) activity decreased, and the superoxide dismutase (SOD) activity did not show significant change (P＞0.05). B. tabaci adults had a higher survival rate and deposited more eggs on the plants treated with IAA. The survival rate of B. tabaci adults and the total number of eggs laid were the greatest in the 50 mg/L IAA treatment, and the survival rate of B. tabaci adults was the lowest in the 250 mg/L IAA treatment. The alkaline phosphatase (AKP) and SOD activities were higher in the treatment groups than in the untreated controls. 【Conclusion】 After tomato plants are sprayed with different concentrations of IAA solution, the physiological and biochemical parameters of tomato change to different degrees, and the survival, oviposition and detoxification enzyme activities of whiteflies on the plants also change to one degree or another. Appropriate doses of IAA could facilitate better performance of whiteflies, by which we can provide more excellent substitutable hosts for breeding wasps.

【Aim】 This study aims to identify the effects of the secondary plant substances, phenolics, on the gypsy moth, Lymantria dispar (L.), and to establish the theoretical foundation to control pests using these phenolics. 【Methods】 We chose four kinds of phenolic acids (salicylic acid, syringic acid, chlorogenic acid and tannic acid), which were mixed in artificial diet separately, to test the influence of phenolics on the growth and development and fecundity of the 2nd instar larvae of L. dispar. 【Results】 The results showed that different phenolic acids had different influences on L. dispar larvae. Tannic acid caused the larval mortality of 22.2% on the 12th day after feeding, which was significantly higher than the mortality in the control (larvae fed on normal artificial diet) (3.3%) (P＜0.01) and treatments with other phenolic acids. The larval mortalities caused by tannic acid and chlorogenic acid increased straightly from the 22nd day and reached 100% on the 34th day after feeding. Both tannic acid and chlorogenic acid reduced the larval weight and prolonged the developmental duration, frequently causing incomplete ecdysis, even all died, at the 4th instar larval stage. The larvae fed on the diet containing salicylic acid or syringic acid pupated and grew to adults, and the pupal weight of females increased significantly but the number of eggs laid per female and fertilization rates of eggs decreased obviously. Compared with the control, syringic acid caused a decrease of 90 eggs in the number of eggs laid per female, a 35% decrease in the fertilization rate of eggs, and also a reduction in the proportion of female adults. 【Conclusion】 The results suggest that different phenolic acids accumulated in pests would result in various degrees of influence on the growth and development and fecundity of the pest.

【Aim】 The green peach aphid, Myzus persicae (Sulzer), and the potato aphid, Macrosiphum euphorbiae (Thomas) are two main potato pests. Our study aims to investigate the effects of temperature on the growth and development, survivorship, reproduction and population growth of the two pests.【Methods】 We determined the indexes of the growth and development, survivorship and reproduction of M. persicae and M. euphorbiae at five temperatures (10, 15, 20, 25 and 30℃) in the laboratory, and constructed the life tables of their laboratory populations at four constant temperatures (10, 15, 20 and 25℃). 【Results】 The developmental periods of immature stages, generation duration, adult longevity and reproduction period decreased as the temperature increased from 10℃ to 25℃, and the development, survivorship and reproduction were restrained at 30℃. The mean generation time (T) decreased with the temperature increasing, and those of M. persicae and M. euphorbiae shortened from 30.08 and 35.35 d at 10℃ to 14.28 and 12.95 d at 25℃, respectively. The net reproduction rate (R₀) of M. persicae was the highest at 15℃ with the value of 86.00, followed by 73.75 at 20℃, 62.49 at 25℃ and 51.00 at 10℃, while that of M. euphorbiae was the highest at 15℃ with the value of 58.97, followed by 51.98 at 10℃, 48.96 at 20℃ and 12.36 at 25℃. The intrinsic rate of increase (r_m) of M. persicae increased from 0.1307 at 10℃ to 0.2896 at 25℃, while that of M. euphorbiae was the highest at 20℃ with the value of 0.2182, followed by 0.1942 at 25℃, 0.1485 at 15℃ and 0.1118 at 10℃. The developmental rates, R₀ and rm of M. persicae were higher than those of M. euphorbiae at the same temperature. 【Conclusion】 These results indicate that temperature significantly affects the growth and development, survivorship, reproduction and population increase of these two potato aphid species, and M. persicae has a stronger growth ability than M. euphorbiae on potatoes. This study provides the foundation for the construction of forecasting models of potato aphids and explains why M. persicae occurs more frequently than M. euphorbiae in potato fields from an ecological view.

5-Hydroxytryptamine (5-HT) is an important biogenic amine in insects, which is synthesized in both neuronal and peripheral tissues and can be reuptaken by serotonin transporter into presynaptic neuron. 5-HT plays various important physiological roles in insects through specific G protein-coupled receptors, such as feeding, circadian behavior, aggregation, learning and memory. There are five types of 5-HT receptors in insects, i.e., 5-HT1A, 5-HT1B, 5-HT2A, 5-HT2B and 5-HT7. 5-HT1A and 5-HT1B inhibit intracellular cAMP production, 5-HT2A and 5-HT2B  increase Ca²⁺ level, and 5-HT7 induces cAMP production. In recent years, great progress has been made in the research of 5-HT in insects, especially their receptors. More and more 5-HT receptor genes have been cloned, and their functions and pharmacological properties have been analyzed. The pharmacological differences of 5-HT receptors from different insects will provide fundamental basis for designing and developing new specific insecticides for pest management.  

Coleoptera is the largest group of all organismal lineages in the world with very high diversity of morphology and ecology. These rich diversity has been attracted many attention by many evolutionary biologists and taxonomists. Along with the development of molecular biology, the molecular biology techniques are widely used for studying the phylogeny of Coleoptera. However, simple molecular fragments can not meet the research requirements. New molecular markers need to be explored. Recently, the mitochondrial genome has become one of the important molecular markers to explore different categories of Coleoptera. In this article, the research progress in mitochondrial genomes of Coleoptera was addressed, and some problems in the application of mitochondrial genomes of Coleoptera were also discussed. So far, the studies of mitochondrial genomes of beetles have mainly focused on gene arrangement and structure of mitochondrial genome, molecular phylogenetics and molecular evolution. Mitochondrial genome has shown many advantages to address the phylogeny and evolution of beetles. However, there are some disadvantages too, such as difficulty to get sequences, simplex gene type, different evolutionary rates, limited application and so on.