【Aim】 ENF peptides identified in Lepidoptera are structurally conserved and play similar roles in many physiological events, including development, immunity and stress response. It was reported that an ENF peptide from silkworm (Bombyx mori) referred to as paralytic peptide (PP) induces immune response through MAPK phosphorylation, whereas its molecular mechanism is still unclear. Our research aimed to investigate the signal pathways activated by PP. 【Methods】 The response of different insect cell lines to PP was evaluated by fluorescent quantitative PCR, and the BmE cell lines in response to PP were screened based on the phosphorylation level of p38 MAPK analyzed by Western blot under the induction of PP. Then inhibitors against a variety of signaling pathways were applied to the BmE cells to screen the molecules involved in signal transmission. 【Results】 The activity of PP in stimulating antimicrobial peptide (AMP) production in BmE cells was abrogated by PI3K inhibitor LY294002 or receptor tyrosine kinase inhibitor Genistein. Furthermore, the dynamic phosphorylation of Akt and certain plasma membrane protein with a molecular mass of 70 kDa in BmE cells and hemocytes was observed in the course of PP stimulation. 【Conclusion】 PP induces the expression of AMPs via PI3K/Akt signaling pathway, and Genisteinsensitive receptor tyrosine kinase is also involved in this immunological activity of PP.

【Aim】 The melanization plays an important role in process of insect cuticle hardening and the immune defense, in which phenol oxidizing enzymes are the key enzymes. Laccase 2 (LAC2), as one of phenol oxidizing enzymes, plays an important role in metamorphosis and immune system of insects. The aim of this study was to explore its expression pattern and hormonal regulation during the cuticle hardening in the cotton bollworm, Helicoverpa armigera. 【Methods】 The fulllength cDNA sequence of lac2 was amplified from the 5th instar larvae of the cotton bollworm by PCR and RACE methods. The expression patterns and hormonal regulation of lac2 were analyzed by using real-time quantitative PCR, hormone treatment and RNA interference methods. 【Results】 The sequence analysis showed that the full-length cDNA sequence of lac2 is 3 221 bp in length with an open reading frame of 2 268 bp encoding 756 amino acid residues. The developmental expression pattern showed that lac2 transcription was richly expressed in the molting stage of every instar and reached a peak in 96 h-5th instar larvae. The spatial expression manifested that lac2 was richly expressed in the cuticle of larvae and in the ovary and antennae of adults. Further hormone treatment showed that juvenile hormone analogue (methoprene) inhibited lac2 transcription, while molting hormone (20-hydroxyecdysone) attenuated methoprene action and induced the expression of lac2. RNA interference of the molting hormone receptors EcR (ecdysone receptor) and USP (ultraspiracle isoform) significantly inhibited the expression of ecr and usp, and injection of dsRNA of ecr and usp followed by injection of 20-hydroxyecdysone also inhibited the transcription of lac2. 【Conclusion】 Altogether, these results provide a foundation for further research of lac2 in insect cuticle hardening and immune defense.

【Aim】 Comparative analysis was performed to investigate differentially expressed proteins between non- and summer-diapausing pupae of the onion fly, Delia antiqua, and to provide a theoretical basis for further exploring the molecular regulation mechanisms of insect diapause and pest control management. 【Methods】 Total proteins were extracted from non-and summer-diapausing pupae, separated by two-dimensional gel electrophoresis, and then analyzed by image analysis. Peptide mass fingerprinting of differential proteins were analyzed by MALDI-TOF MS and identified through database searching in NCBI and SWISS PORT using MASCOT. 【Results】 Proteins were differentially expressed in non- and summer-diapausing pupae. Thirteen differentially expressed proteins were identified by mass spectrometry and bioinformatic analysis, including collagen, SAS6 (spindle assembling abnormal protein 6), MTHFS (5, 10-methenyltetrahydrofolate synthetase), Bnb (bangles and beads) and proteins with unknown functions. 【Conclusion】 The expressions of some proteins are up- or down-regulated in summer-diapausing pupae. Proteins identified in this study may be members of diapause-related protein regulatory networks, and they potentially play important roles in high temperature resistance, chromosome separation, folate metabolism and other physiological processes. 

To examine the enzyme activities and corresponding gene expressions under the stress of cadmium in the lepidopteran model insect, Bombyx mori, which may be used as a bioindicator to monitor heavy metal pollution. 【Methods】 B. mori larvae were exposed to Cd²⁺ in the whole larval stage, the malondialdehyde (MDA) content, and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) as well as their corresponding mRNA levels in the fat body of the 5th instar larvae of both sexes were evaluated. 【Results】 The MDA contents in the fat body in male and female larvae of the silkworm significantly changed in a concentration-dependent manner, increasing with the Cd²⁺ concentration. The activities of both SOD and CAT increased at low exposure dose, which protected silkworms from oxidative stresses. However, the activities of SOD and CAT successively decreased after exposure to high dose of Cd²⁺. According to the analysis of Pearson correlation, the SOD activities were positively correlated with the CAT activities (male: R=0.770,  P=0.001; female: R=0.854,  P=0.000). The CAT activities and its mRNA expression levels showed positive correlations in the fat body in females (R=0.712, P=0.003). The GSH-Px activities in the fat body in males changed in a concentrationdependent manner, increasing with the Cd²⁺ concentration, and those in females exposed to 12.5-50 mg/kg Cd²⁺ were significantly higher than the control (P<0.05). The changes of the GSH-Px actity and its mRNA level showed positive correlations (R=0.834, P=0.000). However, the GSH-Px activities in females increased at low exposure dose, and those in females exposed to 12.5 mg/kg Cd²⁺ were significantly higher than the control (P<0.01). 【Conclusion】 These results show that acute exposure of the silkworm to Cd²⁺ has the toxic effect on its fat body, and this might be related to the increase in lipid peroxidation and the changes of the antioxidative enzyme activities. The results also suggest that detoxifying strategies in the silkworm against Cd²⁺ exposure seem to be sex-dependent.

【Aim】 Wolbachia are endosymbionts which were frequently found in arthropods and filarial nematodes. They can manipulate reproduction of their hosts by several mechanisms. Cytoplasmic incompatibility (CI) is the most common phenotype Wolbachia causes, resulting in no or few viable progenies when Wolbachia-infected males cross with uninfected females or females carrying different Wolbachia strains, while the progenies can be produced normally when males and females carrying the same Wolbachia strain cross. We previously found that Drosophila melanogaster flies collected from Wuhan of Hubei (WH), Liuku of Yunnan (LK) and Tianjin (TJ) were infected by Wolbachia. This study aims to investigate the relationships between Wolbachia in these D. melanogaster populations and their effects on host reproduction. 【Methods】 Alignments of nucleic acid homology of Wolbachia wsp genes were performed by Clustal X, and phylogenetic tree was constructed with MEGA. Sequence types (ST) of Wolbachia were analyzed using multilocus sequence typing (MLST). Crossing experiments within and between the three populations of D. melanogaster were conducted to assay CI intensity and the effect of Wolbachia on reproduction of Drosophila hosts. 【Results】 All Wolbachia in the three populations of D. melanogaster belonged to Mel group in supergroup A. MLST analysis showed different sequence types (ST) of Wolbachia in the flies from the three regions. The Wolbachia in the flies from WH and TJ could induce strong CI. Comparatively, the Wolbachia in the flies from LK expressed weaker CI. The Wolbachia in the flies from WH could not entirely rescue the CI phenotype induced by the Wolbachia in TJ flies, and vise versa. 【Conclusion】 The Wolbachia in the flies from WH might be less related with those from TJ. The long-time symbiosis of Wolbachia might affect the evolution of their Drosophila hosts. Wolbachia in WH and LK populations of D. melanogaster belong to different STs, and a definite reproductive isolation between their hosts exists.

【Aim】 Research the influence of fluoride on the retained enzyme-producing bacteria in the intestine of the silkworm, Bombyx mori so as to contribute to understanding the difference of the enduring fluoride between fluoride-resistant and sensitive varieties. 【Methods】 Fluoride-resistant variety T6 and fluoride-sensitive variety 734 of the silkworm were fed with fresh mulberry leaves soaked in NaF solution until the 3rd day of the 5th instar for experiment. Protease-, cellulase-, lipase- and amylase-producing strains were screened on selection medium, and the taxonomic composition of the intestinal bacterial community was identified according to phylogenetic relationship based on 16S rDNA sequences. 【Results】 Genera producing digestive enzymes in the silkworm intestine included Bacillus, Staphylococcus, Enterobacter, Acinetobacter, and Exiguobacterium, among which Bacillus sp., Staphylococcus sp. and Acinetobacter sp. bacteria produced four kinds of enzymes at the same time. The species of enzyme-producing bacteria in the intestine of T6 and 734 varieties reduced from 5 to 4 and 2 to 1, respectively after fluorosis. 【Conclusion】 The retained enzyme-producing bacteria in silkworm intestine are related to the ability of enduring fluoride of silkworm.  

【Aim】 Honeybees are important pollinators, but they are endangered by neonicotinoid insecticides like imidacloprid which mainly impair nerve cells of honeybee brain. Our research aimed to explore the apoptosis in the nerve cells of Apis mellifera ligustica brain induced by imidacloprid. 【Methods】 Apoptosis was detected in the nerve cells of honeybee brain by TUNEL labeling, cleaved Caspase-1 was detected by immunofluorescence, and the ultrastructure of nerve cells in the brain of adult worker honeybees was observed by transmission electron microscope after treatment with the sublethal dose of imidacloprid (9.90 ng/individual). 【Results】 An overall observation at seven selected sites of the brain indicated that the apoptotic rate induced by orally administrated imidacloprid at sublethal dose (9.90 ng/individual) increased with treatment time and showed significant differences between the treatment group and the control group at 9 and 12 d after treatment (P<0.01). The proportion of Caspase-1 positive cells also increased with the treatment time, and significant differences were observed at 3, 6, 9 and 12 d after treatment (P<0.01). The apoptotic rate and the proportion of Caspase-1 positive cells changed in a timedependent manner, and both showed a positive correlation. The observed ultrastructure of apoptotic nerve cells demonstrated important characteristics of apoptosis and autophagy including cell shrinkage, chromatin condensation, presence of apoptotic bodies and autophagosomes, and swollen mitochondria, some of which were enclosed by autophagic vacuoles and mitophagy occurred. 【Conclusion】 These findings suggest that at the cellular level, a sublethal dose of imidacloprid can induce nerve cell apoptosis in the brain of adult worker honeybees, and the apoptotic pathway is related to Caspase-1 and autophagy. This study provides a useful theoretical basis for estimating the harm of pesticides on non-target organisms.

【Aim】 To study the insecticidal potential and active ingredients of essential oil from horseweed Conyza canadensis (L.) Cronq. 【Methods】 The insecticidal activity of the essential oil against Aedes albopictus and Culex pipiens quinquefasciatus was assayed with immersion method and fumigation method. The volatile components of this oil were also qualitatively analyzed by gas chromatographymass spectrometry. 【Results】 The  LC50 values of the essential oil from C. canadensis against the 1st-4th instar larvae and pupae of Ae. albopictus at 24 h after treatment were 25.01, 45.88, 56.94, 64.60 and 346.23 μg/mL, respectively, while those against the 1st-4th instar larvae and pupae of Cx. pipiens quinquefasciatus were 9.16, 8.65, 32.12, 43.68 and 197.83 μg/mL, respectively. At the dosages of 48, 64, 80, 96, 112 and 128 μg/cm³, the KT₅₀ values of the essential oil from C. canadensis against adults of Ae. albopictus and Cx. pipiens quinquefasciatus were 28.81, 22.31, 20.38, 17.05, 13.92 and 9.74 min, and 34.90, 32.97, 23.97, 19.60, 15.20 and 10.34 min, respectively. The LC₅₀ values of the essential oil against adults of Ae. albopictus and Cx. pipiens quinquefasciatus at 24 h after fumigation  were 75.46 and 99.19 μg/cm³, respectively. Thirty-one compounds were separated and identified from volatiles of C. canadensis essential oil, including 6 monoterpenes, 17 sesquiterpenes and 6 oxygenated sesquiterpenes. 【Conclusion】 These results demonstrate that the insecticidal activity of C. canadensis essential oil against the two mosquito species is remarkable and the oil has a potential for further development.

【Aim】  Galeruca daurica Joannis began to outbreak seriously since 2009 and has caused great losses in the Inner Mongolian grasslands. Its occurrence region has expanded constantly and the damage has become more and more severe, which greatly influenced the sustainable development of grassland animal husbandry and ecological safety in Inner Mongolia. Low temperature is a key factor that affects the development and survival of insects, and their overwintering survival mainly depends on their tolerance to low temperature in winter. Understanding the supercooling point (SCP) and cold hardiness of G. daurica is helpful to forecast its distribution and population dynamics. 【Methods】  We measured the supercooling points in various developmental stages in the laboratory and determined the survival rates of larvae exposed to different low temperatures (-6℃--14℃) for 2 h or exposed to -5℃ for different periods (0.5-8 d) with the thermocouple method. 【Results】  The supercooling points had obvious differences among various developmental stages of G. daurica in the following order from low to high: egg (-29.8℃), 1st instar larva (-14.6℃), 2nd instar larva (-13.3℃), pupa (-12.1℃), 3rd instar larva (-10.2℃) and adult (-9.0℃). The SCPs of eggs were the lowest in December and January, and the highest in February. The survival rates of larvae declined with the decrease of treatment temperature and the extension of treatment time.  For 1st instar, 2nd instar and 3rd instar larva, the half lethal time of individuals (Ltime₅₀) at -5℃ was 3.84 d, 3.80 d and 2.28 d, respectively, while the lower lethal temperature needed to kill 50% of individuals (Ltemp₅₀) after 2 h exposure was -10.1, -9.1 and -8.5℃, respectively, higher than the corresponding SCPs. 【Conclusion】  The larvae of G. daurica can be considered as chillintolerant.

【Aim】 The peach fruit moth, Carposina sasakii Matsumura, is one of the most damaging pests in apple orchards in North China. We explored the influence of brief exposure to high temperature on the development and reproduction of the pest. 【Methods】 The developmental duration and survival rate of each life stage and fecundity were measured in the laboratory under the conditions of temperature 23±1℃, RH 80%±7%, and photoperiod 15L∶9D, after the eggs, larvae, pupae, and adults were exposed to high temperatures of 35, 38, and 41℃ for 1-4 h. 【Results】 High temperature had no significant effect on the hatchability of eggs. The larval duration significantly prolonged and the survival rate significantly decreased in 1-day-old larvae exposed to 41℃, while no significant effect was found on 3-day-old or over 3-day-old larvae exposed to 41℃. The emergence rates decreased and the deformity rates increased significantly in 11-day-old pupae exposed to 38 and 41℃. The longevity shortened and the survival rates and fecundity decreased significantly in female adults exposed to 38 and 41℃. 【Conclusion】  Brief exposure of C. sasakii to high temperature imposes less effect on its egg than on its adult. The results could improve our understanding of the mechanisms responsible for population dynamics of C. sasakii during high temperature season.  

【Aim】 Differences in biological characteristics between the natural population collected from the wild and the laboratory population reared more than 50 generations of the oriental fruit moth, Grapholita molesta (Busck), were investigated to estimate if the laboratory population has the evidence of degeneration. 【Methods】 The main biological characteristics of the natural and laboratory populations of G. molesta bred under the same indoor conditions were investigated respectively and their life table parameters were comparatively analyzed. 【Results】 The results showed that the pupal stage of the laboratory population was extremely significant longer than that of the natural population (t=-10.78, df=4, P=0.0004), and the egg stage, larval stage and pre-pupal stage of the laboratory population were slightly longer than those of the natural population. The larval survival, pupation and eclosion rates of the laboratory population were extremely significant higher than those of the natural population (larval survival rate: t=-7.61, df=4, P=0.0016; pupation rate: t=-24.32, df=4, P=0.0017; eclosion rate: t=-6.96, df=4, P=0.0022), but there was no significant difference in egg hatch rate, pupal weight, the longevity of female and male adults, pre-oviposition duration, oviposition duration as well as the number of eggs laid per female between the two populations. The rate of fruits bored by the natural population was slightly higher than that bored by the laboratory population. The results of life table showed that the population trend index (I), the net reproduction rate (R₀), the intrinsic rate of increase (r_m), the mean generation time (T), and the finite rate of increase (λ) of the laboratory population were extremely significantly higher than those of the natural population (I: t=-12.20, df=4, P=0.0003; R₀: t=-11.72, df=4, P=0.0003; r_m: t=-9.77, df=4, P=0.0006; T: t=-12.05, df=4, P=0.0003; λ: t=-9.79, df=4, P=0.0006), but the population doubling time (D_t) of the laboratory population was extremely significantly lower than that of the natural population (t=7.17, df=4, P=0.0020). 【Conclusion】 After domestication of more than 50 generations, the laboratory population, whose life table parameters and damage rate do not decline, shows a better adaptability and a greater population growth potential than the natural population. Our results suggest that the laboratory population can be a preferred material for conducting experiments.

【Aim】 To explore the species composition and distribution characteristics of the bumblebee Bombus lucorum complex in China. 【Methods】 DNA (COI) barcodes were used to identify larger new samples of B. lucorum complex from China and then the distribution patterns of these species were plotted using these samples. 【Results】 B. lucorum complex in China includes four cryptic species, i. e., B. terrestris, B. cryptarum, B. lucorum and B. longipennis. From a total of 160 COI barcode sequences from the four species, 36 unique haplotypes were identified, with the highest diversity occurring within B. longipennis (14 haplotypes) and the lowest within B. terrestris (3 haplotypes). The longest genetic distance (0.077) was found between B. terrestris and B. lucorum, and the shortest (0.034) was found between B. lucorum and B. longipennis. Phylogenetic analysis of Bayesian and Maximum-likelihood methods showed that the divergence of the four species occurred in the order of B. terrestris, B. longipennis, B. lucorum, and B. cryptarum. Distribution patterns differed among the four species. The mean elevation of the four species ranks from high to low in the order of B. longipennis, B. cryptarum, B. lucorum, and B. terrestris. B. longipennis was found only at high elevation in the eastern and the southern Qinghai-Tibetan plateau, while B. terrestris was found only at low elevation in northwestern Xinjiang. 【Conclusion】 This study clarifies the species composition and distribution patterns of the bumblebee B. lucorum complex in China, which will be useful for further studies on resource conservation of these valuable bumblebee taxa and their use in agricultural pollination.

This paper presents a taxonomic review of the genus Parapachymorpha Brunner von Wattenwyl, 1893 from China. Two new species, Parapachymorpha daoyingi sp. nov. and P. xishuangbannaensis sp. nov., are described. Parapachymorpha spinosa Brunner von Wattenwyl, 1893 is recorded for the first time from China. The type specimens of the new species are deposited in Shanghai Entomological Museum, Shanghai.

Because of the efficient pollination for many natural plants and crops, honey bees (Apis spp.) are of great value in economy and ecology. As a highly eusocial insect, the honey bee has become a model organism in sociobiology. The reproductive division of labor, based on the caste differentiation in social insects is of great significance in evolution. Many important findings about honey bee caste differentiation have been obtained in recent years, and the mechanisms underpinning this process were well elucidated. Different nutritional stimuli trigger the caste differentiation of honey bee larvae. Royalactin, a major protein component of royal jelly, is found to be the key nutritional factor inducing queen development. The queen inducing function of royalactin is mediated by the epidermal growth factor receptors (Egfr) in fat body cells. DNA methylation, one of the important epigenetic mechanisms, is associated with the development and disease of vertebrates. Recently, it is evident that DNA methylation is also involved into the regulation of honey bee caste differentiation. Moreover, more and more findings have deepened people’s understanding of the important regulation roles of endocrine system in the caste differentiation. In this article, we reviewed the mechanisms of honey bee caste differentiation from three aspects, i.e., the key nutritional factors, epigenetic regulation, and endocrine modulation. We also proposed several directions for future studies in this area.

【Aim】 To understand the characteristics of community structure and spatial distribution of ectoparasite fleas on rodents in residential areas in Yunnan province, southwestern China. 【Methods】 The systematic investigation on the fauna and community ecology of ectoparasite fleas on rodents were carried out in residential areas of 17 counties of Yunnan province, southwestern China with different longitude, latitude and elevation from May 2007 to November 2012. The characteristics of the spatial distribution of flea communities along environmental gradients were analyzed using community structure indexes. 【Results】 A total of 521 fleas were collected from the body surface of rodents from residential areas in the seventeen counties, and these fleas were classified into 12 species of 9 genera in 7 subfamilies of 4 families. The vertical and latitudinal distributions of fleas were similar in residential areas. The number of flea species was relatively less in the low latitude and altitude range, and Xenopsylla cheopis and Leptopsylla segnis were the dominant species of indoor parasitic fleas. However, in the high latitude and altitude region, although more species were found, the dominant species was not prominent. The horizontal distribution of flea species richness showed one peak along the longitudinal gradient, and the highest richness was observed at the longitude 99°-101°E. The indoor dominant species X. cheopis and L. segnis can be distributed in almost all longitudes, displaying a wide ecological amplitude feature. In addition, the richness and diversity spatial distribution patterns of fleas showed the similar trends of leaning peak curves, first gradually increasing and then decreasing with the increase of latitude and elevation. The geographical distribution of flea species diversity, however, showed gradually decreasing tendency from west to east in longitude distribution. 【Conclusion】 The spatial patterns of fleas communities in residential areas show unique geographic characteristics in Yunnan, and the characteristics are affected by different habitats of fleas which are influenced by a variety of factors such as climate, forest vegetation and human activities.