The silkworm, Bombyx mori, is an important economic insect and a model for Lepidoptera insects；the mutants of silkworm are the valuable resources for physiology, genetics and functional genomics. We discovered a new body shape mutant named Squab (Sq) during the conservation and genetic analysis of the silkworm resources. The heterozygote (Sq/+) could survive, and the length of mutant is just about four-fifths of the normal and is characterized by slight fat abdomen in the middle region and a little narrow thorax; the homozygote (Sq/Sq) is embryonic lethal. The genetic analysis showed that it was controlled by dominant mutant gene. It is confirmed that the mutant gene Sq belongs to the 14th linkage group by crossing it with the marker genes for each linkage group. Three-point test among aojuku translucent (oa), dirty (Di) and Sq showed that the gene locus of Sq is at 34.6 cm on the 14th linkage group in silkworm linkage map. This study has important significance for further research and utilization of this mutant.

Temperature tolerance of 5th instar larvae and pupae of three races of the silkworm, Bombyx mori at 35, 38 and 40℃ was studied. LT50 values and feducial limits were determined in each case by Probit analysis.  The multivoltine Pure Mysore showed better survival to high temperature treatment than the two bivoltine races. NB4D2 showed better temperature tolerance than CSR2 in the two bivoltine races.  The 90, 70 and 29 kDa heat shock protein bands appeared in the haemolymph after exposure of the larvae to 38℃ for 6 h and to 40℃ for 3 h. The 29 kDa protein band could not be detected in the haemolymph of bivoltine larvae during recovery.  But, expression of the 29 kDa protein was sustained during recovery in the larvae of Pure Mysore. When pupae were held at high temperature, the 90 and 70 kDa proteins were expressed, while the 29 kDa protein was not detected in the haemolymph. These results suggest that heat shock protein expression is associated with the occurrence of thermotolerance among tropical silkworm breeds, and growth stages within a breed.

Suppression of host immune response after parasitization is essential for the survival of endoparasitoids. In Plutella xylostella (L.) (Lepidoptera: Plutellidae) larvae parasitized by Cotesia vestalis (Haliday) (Hymenoptera: Braconidae), how the parasitoid egg avoids encapsulation by the host’s immune attack is still not well understood. In this study, the ultrastructure of C. vestalis egg surface was investigated systematically using electron microscopes. The results showed that the egg possesses a fibrous layer, which is coated by an overlying sheath of virus-like filaments. During oviposition, C. vestalis lays an egg into the hemocoel of the host larvae, together with calyx fluid mainly including polydnavirus. Both the outer virus-like filaments and the fibrous layer of parasitoid eggs seem to be the first passive protection barrier to host immunity during the initial stages of parasitism. They may delay encapsulation until a more permanent means of suppressing encapsulation is established. Afterwards, polydnavirus plays a great role in the immune suppression of recognition and encapsulation by host hemocytes. Within eight days post pseudoparasitization by C. vestalis, the encapsulation response of P. xylostella larval hemocytes to the irradiated eggs was strongly suppressed, indicating that the polydnavirus has a permanent immunosuppressive capability. The results suggest that in the system of C. vestalis-P. xylostella, C. vestalis avoids the host immune reaction by a combination of both passive and active mechanisms.

Thanatin is one of the antibacterial peptides which consists of 21 amino acids and has a broad spectrum of antimicrobial activities. To explore a cost-effective approach for highlevel expression of the thanatin in Escherichia coli, the cDNA fragment encoding thanatin with preferred codons of E. coli was obtained by recursive PCR (rPCR) and fused to the C-terminal of ubiquitin (UBI) from housefly, Musca domestica. The fused gene was inserted into the plasmid pET32a to construct the expression vector pET-TRX-UBI-THA and express the fusion protein with 6×His tag in E. coli BL21. The fusion protein was expressed in soluble form under the optimized conditions at a high-level (more than 46% of the total proteins). With 6×His tag, the proteins were easily purified by Ni²⁺-NTA chromatography. The purified proteins were efficiently cleaved by ubiquitin carboxyl-terminal hydrolase which linked with 6×His tag at the carboxyl-terminus (UCH-6×His), yielding recombinant thanatin with significant antimicrobial activity. After contaminants removal by Ni²⁺-NTA chromatography, recombinant thanatin was purified by reversed phase HPLC, 5.4 mg of pure active thanatin was obtained from 1 L culture medium. ESI-MS analysis showed that the molecular weight of the purified recombinant thanatin was 2.57 kD, which perfectly matched the mass calculated from the amino acid sequence. The antimicrobial assay showed that the purified thanatin has high activities against E. coli K12D31 and Staphylococcus aureus. Our results demonstrated that functional thanatin can be produced in sufficient quantity using the ubiquitin fusion technique at a low cost.

The red imported fire ant, Solenopsis invicta Buren, is a social insect pest found recently in mainland China. To elucidate the cold hardness and provide basis for its risk assessment in mainland China, the supercooling points (SCPs) of various castes and individuals of various developmental stages collected from different geographical locations, seasons and durative starvations treatment were examined. The results indicated that the SCPs of fire ants differed significantly among castes and developmental stages. The worker ants had significant lower SCPs (－11.8±0.4℃) than those of female alates (－8.1±0.6℃) and queens (－7.9±0.5℃). The SCPs of the pupae and larvae of workers and queens were －13.6±0.3, 12.1±0.4, 13.3±0.3 and 12.2±0.3℃, respectively. Worker pupae had lower SCPs than worker adults and worker pupae. There was no significant difference between queen larvae and its pupae. At the same immature stage, SCPs of various castes did not differ from each other. The SCPs were not significantly different in workers collected from different geographical locations of Luchuan, Guangzhou, Zhuhai and Shenzhen in spring, autumn and winter except those collected in summer, when workers in Luchuan had remarkable lower SCPs than other locations (P<0.05). SCPs of worker ants decreased as the season progressed, with the highest for spring (-4.3±0.2℃), the second for summer (－6.6±0.2℃), and third for autumn (－9.4±0.1℃) and lowest (－12.0±0.3℃) for winter colonies. The SCPs of worker ants increased greatly by a durative starvation for 15 d. The SCPs of major workers and minor workers increased 7.0℃ and 4.9℃, respectively during the starvation test, suggesting that the major workers are less resistant to starvations than the minor workers. These results will support theoretically for risk analysis of Solenopsis invicta potential disperse in China.

【Objective】To determine whether the porcine reproductive and respiratory syndrome virus (PRRSV) can survive in mosquitoes in infected pig farms. 【Methods】 The mosquito samples were collected from 3 pig farms infected by the porcine reproductive and respiratory syndrome (PRRS) and determined by RT-PCR method based on the primers of PRRSV N gene, then the PCR-positive mosquitoes were cultured in Marc-145 cells for isolation of PRRSV, which was identified by indirect immuno-fluorescence assay and sequence analysis of Nsp2 gene. 【Results】 At least 4 mosquito species, Culex tritaeniorhychus, Culex modestus, Anopheles sinensis and Armigeres obturbans were identified on 3 pig farms and C. tritaeniorhynchus was found to be the predominant species (86.76%). By RT-PCR, PRRSV was detected in the samples of Culex tritaeniorhychus but none in other 3 mosquito species. The cell pathological effects such as cell fusion and cavitation were observed in Marc-145 cells inoculated by the samples of C. tritaeniorhynchus. The antigen of PRRSV in cultural cells was detected by indirect immunofluorescence assay. The PRRSV NSP2 gene, which was amplified and sequenced from infected moisquito cells, was highly homologous in nucleotide sequence with those from the infected pigs in same farm. 【Conclusion】C. tritaeniorhynchus is the predominant species and PRRSV can survive in this mosquito.

Insecticidal compounds from seeds of yam bean Pachyrrhizus erosus (L.) Urban were studied in order to determine their insecticidal toxicity. Using the 4th instar larvae of Aedes albopictus as target insect pest, the active ingredients were isolated from the methanol extracts of the seeds by activity-directed fractionation with column chromatography and thin layer chromatography (TLC), and identified predominantly on the basis of NMR data. Insecticidal activities and action mode of these compounds were determined against the 4th instar larvae of A. albopictus, Aphis gossypii apterae, the 3rd instar larvae of both Herse convolvuli and Plutella xylostella by leaf dip method, topical application and leaf disk method, respectively. Fourteen compounds were isolated and identified, which were 12α-hydoxyrotenone, pachyrrhizine, 12α-hydoxypachyrrhizone, 12α-dehydropachyrrizone, α-naphthoflavone, 7-methoxyflavanone, 12a-hydroxydolineone, 6-methoxyflavone, 4′-hydoxyflavanone, quercetin dehydrate, 5-methoxyflavone, 7-hydroxyflavone, 3′-hydoxyflavanone and 3-hydroxyflavone. The results of bioassay showed that among the 14 compounds, the former seven possessed insecticidal activity against A. albopictus larvae, with corresponding LC₅₀ values at 24 h after treatment being 25.0, 51.1, 196.2, 48.4, 98.9, 107.2 and 15.6 mg/L, respectively; the former six exhibited insecticidal activity against A. gossypii apterae, with the LC₅₀ values at 24 h after treatment being 1.5, 10.9, 80.7, 66.8, 32.1 and 112.8 mg/L, respectively; the former five and 12α-hydroxydolineone had insecticidal activities against H. convolvuli larvae; 12α-hydoxyrotenone exhibited stomach toxicity to the 3rd instar larvae of P. xylostella, with the LD₅₀ values being 17.3 μg/individual at 24 h after treatment, while 7-methoxyflavone only possessed weak growth inhibition activity to the insect pest. Nine-compounds (6-methoxyflavone, 4′-hydoxyflavanone, quercetin dehydrate, α-naphthoflavone, 7-methoxyflavanone, 5-methoxyflavone, 7-hydroxyflavone, 3′-hydoxyflavanone and 3-hydroxyflavone) were isolated from the seeds of P. erosus for the first time. There were seven insecticidal compounds altogether from the seeds, whose action modes to the different tested insects were different. The main insecticidal ingredient was not rotenone but 12a-hydoxyrotenone.

The resistance levels to various insecticides, the distribution of the esterase genotypes, and the genetic diversity of five different field samples of Culex pipiens complex were studied by bioassay, protein electrophoresis, and the analysis of resistant alleles. Using the sensitive lines S-LAB as the control, the bioassay results indicated that the five Cx. populations showed higher resistance against dichlorovos, parathion, deltamethrin and permethrin, but lower resistance against propoxur, bassa, and tetramethrin. Chaoyang population had the highest resistance (55.7-fold) to dichlorovos, followed by Wuhan population. Foshan population also had higher resistance levels with 123-fold to permethrin and 23.9-fold to deltamethrin. The esterase electrophoresis indicated that the five Cx. populations showed different phenotype polymorphisms. The esterase of the Cx. populations from Guangzhou and Foshan exhibited the highest phenotype polymorphism with B1, A2-B2, A8-B8, A9-B9, B10 and A11-B11, suggesting that the over-produced esterases be the main mechanisms for resistance. Population genetics results indicated that the number of average allele, average polymorphism site, average expected heterozygosity, differentiation coefficient (Fst) and average gene flow (Nm) were 2.76, 66.45%, 0.1943, 0.10 and 2.57, respectively. The results showed that the five Cx. populations have a wealth of genetic diversity and the genetic diversity within populations is higher than that between populations. It is so inferred that the genetic diversities and the resistance levels became more identical through gene communication among the field populations by migration or others. This study may provide a guide to integrated pest management for Cx. pipiens complex in China.

The life tables of small brown planthopper (SBPH) Laodelphax striatellus Fallèn on different host plants including five rice varieties (Wuyujing No. 3, Yandao No. 8, Xudao No. 3, Eryou No. 084 and Eryou No. 42), one wheat variety (Yangmai No. 12), and two weed species (Echinochloa crusgalli and Leptochloa chinensis) were compared in the laboratory, and the population dynamics of SBPH on two different rice varieties was investigated in fields. The life tables of experimental population of SBPH showed that the nymphal duration on E. crusgalli was 23 d which was the shortest, while those on Eryou No. 084, Eryou No. 42 and L. chinensis were nearly 30 d. The index of population trend (I) of SBPH on E. crusgalli was the highest (I=45.57), which was not significantly different from that on Yandao No.8 (I=39.36), but significantly different from that on the other tested plants. Moreover, the index of population trend on indica hybrid rice such as Eryou No. 084 (I=20.46) and Eryou No. 42 (I=19.53) was significantly lower than those on japonica rice such as Yandao No. 8, Xudao No. 2 (I=34.53) and Wuyujing No.3 (I=31.70), and the index of population trend on L. chinensis was the lowest (I=11.04). Field investigation indicated that the number of SBPH on japonica rice Wuyunjing No.7 was higher than that on indica hybrid rice Eryou No. 084, while there was no steady difference of SBPH on the tested rice varieties in plots. The results suggest that E.crusgalli is the most suitable host plant of SBPH,followed by japonica rice varieties and then wheat.

To probe into either the attractiveness to or avoidance from phylloxera of grape rootstocks and cultivars with different tolerance, as well as into the volatile components from their roots, the method of invitro root segment culture was used to investigate the selectivity of Phylloxera viticola Fitch to the roots of grape rootstocks ‘5BB’ and ‘140Ru’ and cultivar ‘Kyoho’. The results showed great selectivity of phylloxera to ‘Kyoho’ roots relative to ‘5BB’ and ‘140Ru’. Three days after inoculation, 67.13% grape phylloxera selected ‘Kyoho’, while only 15.29% and 17.58% phylloxera selected ‘5BB’ and ‘140Ru’, respectively. The results also demonstrated significant difference in development and reproduction of grape phylloxera on the root segments of ‘Kyoho’, ‘5BB’ and ‘140Ru’. In addition, the volatile components from the roots of ‘Kyoho’ and ‘5BB’ were determined. It was found that each of them produced a large number of unique volatile components. ‘Kyoho’ produced 23 unique volatile components accounting for 48.94% of the total, while ‘5BB’ had 32 accounting for 57.14%. Among these volatile components, 24 were shared by ‘Kyoho’ and ‘5BB’, which were linoleic acid, methyl ester and elaidic acid, methyl ester with different contents. The contents of caryophyllene, linoleic acid (methyl ester), elaidic acid (methyl ester), and hexadecanoic acid (methyl ester) in 5BB roots were 4.23%−6.46％ higher than those in ‘Kyoho’ roots, while the contents of dibutyl phthalate and cholestane in ‘Kyoho’ roots were 6.81% and 1.07% higher than those in 5BB roots, respectively. The results suggest that phylloxera has different selectivity to grape rootstocks and cultivars with different tolerance, and these rootstocks and cultivars produce different volatile components.

In order to identify significant indicators, and thereby reveal the important relationship among the quantitative changes of Hemiberlesia pitysophila, the changes of environmental factors and the hazard degree of masson pine, four standard areas where the Hemiberlesia pitysophila occurred in Fujian Province were selected for the survey. Moreover, six quantitative indicators of Hemiberlesia pitysophila, six environmental factors and the hazard degree of masson pine were investigated, and then the results of investigation were analyzed by using the integrated correlation coefficient analysis. The results showed that environmental factors had significant integrated negative correlation with the quantitative indicators of Hemiberlesia pitysophila: besides total N, total P and temperature, the female adult population density, the male adult population density, and the second instar nymph density were important indicators. Furthermore, quantitative indicators of Hemiberlesia pitysophila had significant integrated positive correlation with the hazard degree of masson pine, but environmental factors had no significant integrated correlation with the hazard degree of masson pine. The various results obtained using the integrated correlation coefficient analysis were very coherent, and basically in line with reality. So, it is concluded that the environmental factors has significant influence on the hazard degree of masson pine, the quantitative change of Hemiberlesia pitysophila has important influence on the hazard degree of masson pine, while environmental factors has little influence on the hazard degree of masson pine. The integrated correlation coefficient analysis with a certain degree of innovation and practicality is scientific and rational, and is worthy of study and popularization.

In this paper, the species composition, richness, abundance and diversity of flower-visiting hoverfly (Diptera: Syrphidae) communities in habitats with various degrees of disturbance and altitudes in Changbai Mountain, N. E. China, were investigated using transect sampling method in two sample sites. One site located at a low elevation of 800-1 100 m, and the other located at a high elevation of 1 750-2 150 m. In each sample site, three types of habitats were selected, with an area of 20 m×20 m for each transect (habitat). A total of 2 540 individuals of 42 Syrphidae species in 252 sets of data were collected. The differences in flower-visiting hoverfly composition, species richness, abundance and diversity in different habitat types and altitudes were analyzed. The results showed that the similarities among different habitats at the low site are higher than those of the high site. The flower-visiting hoverfly abundance at the low site is higher than that of the high site, while the species richness is lower than that at the high site. The diversity indexes of flower-visiting hoverfly are significantly different among different habitats, but diversity shows no significant differences between the low and high altitude sites. In different habitats, the highest diversity of flower-visiting hoverfly occurred in the transition forest habitat (Betula ermanii forest belt), as well as in the secondary forest habitats with slight disturbance (coniferous-deciduous mixed forest beltⅡ). The diversity flower-visiting hoverfly in Botanical Garden for valuable plant species conservation is second only to that in the above two habitats, which indicates its remarkable effect on conservation.

Nine species and one subspecies of the genus Narosa Walker are recognized from China, including a new species, N. pseudopropolia, described herein. N. propolia Hampson is reported for the first time in China. The adult and genitalia photographs of the examined species are given. A key to the Chinese species of the genus is provided.

The complex of insect innate immunity is evolved in a long-term for self-defense. Pathogen recognition mediated by different pattern recognition proteins (PRPs) plays a vital role in the first step of activating the immune responses. To date, different PRPs, including peptidoglycan recognition proteins (PGRPs), immunoglobulin, β-1, 3-gulcans binding proteins (βGBPs), C-type lectins and multi-functional apolipoproteins, as well as their functions in the process of recognizing molecular patterns of various insect pathogens, have been identified. To counteract host recognition, however, insect pathogens also have evolved strategies of camouflage and masking to invade insect immune responses and develop diseases or eventually kill the insect hosts. This article mainly dealt with recent advances in the mechanisms of insect immune recognition and immune escape. The former includes the binding targets, protein structures and functions of different PRPs, and the latter mainly focuses on the anti-immune strategies developed through different pathogens. Future studies on insect immunology and the mechanisms of microbial pathogenesis are discussed in some detail. Most importantly, only when the studies on immunity and pathology are well combined, can the dynamic molecular interactions between insect hosts and pathogens be properly understood.