【Aim】 Variation in coloration is frequently found in insects, but little is known about its functional value.  Drosophila takahashii exhibits genetically coded discontinuous variation in abdominal melanisation. To determine whether physiological performance is likely to be affected by melanisation pattern, in this study we investigated the variation in abdominal melanisation and stress related traits among individuals belonging to three different color morphs, and tested the hypothesis that seasonal environmental conditions would enhance the adaptation of the corresponding seasonal phenotype. 【Methods】 D. takahashii  flies were collected from altitudinal sites and a Mendelian analysis of genetic crosses from true breeding dark and light color strains confirmed the occurrence of a major locus, with dominance of D allele. Ecophysiological traits in populations as well as flies of three body color phenotypes were statistically analyzed. 【Results】A significant increase in the frequency of the dark allele was observed during the dry season and lighter flies occur in the wet season, which suggests that climatic selection plays a role. However, intermediate flies were abundant in both seasons. There were significant  F  values for increase in all traits for intermediate phenotypes ( P<0.001) due to acclimation but no such acclimation effects were observed in dark and light true breeding strains of D. takahashii (P ≥0.42). 【Conclusion】 As per our hypothesis, significantly higher physiological tolerance was observed in dark morph under cool-dry stress conditions, and in light morph under hot-wet conditions, respectively, as determined by different traits. Interestingly, intermediate phenotypes showed higher capability to acclimation to both conditions. Further, we found seasonal changes in temperature and humidity to confer selection pressures on stress-related traits.

【Aim】 The dark black chafer, Holotrichia parallela, locates the mate and host plant accurately and rapidly by binding of the odorant binding proteins (OBPs) with sex pheromones and plant volatiles. This study aims to clone the open reading frame (ORF) of odorant binding protein 15a (HparOBP15a) gene from H. parallela, as well as to gain insight into the characteristics of its encoding protein, its expression patterns, and characterize the binding profiles of OBP15a with a number of plant volatiles, and will provide a theoretical basis for a better understanding of the chemosensory mechanism of H. parallela.【Methods】 Based on transcriptome sequencing of the adult antenna of H. parallela, reverse transcription-polymerase chain reaction (RT-PCR) was used to amplify the ORF of HparOBP15a. The mRNA levels of HparOBP15a in different tissues of adults were assayed by real-time quantitative PCR (qRT-PCR). Binding affinities of HparOBP15a towards 58 compounds, which are probably associated with the chemosensation of  H. parallela, were measured by fluorescent competitive binding assay. 【Results】 HparOBP15a has a full-length cDNA of 534 bp, encoding 147 amino acids, and its corresponding sequence was submitted to GenBank under the accession number AK1834747. The qRT-PCR assay indicated that  HparOBP15a mRNA was specifically expressed in the antennae of female adults. Among the 58 chemicals tested, HparOBP15a exhibited a good affinity to 46 kinds of ligands. Notably, it was found that HparOBP15a had the strongest binding affinity to dodecane and 1-dodecanol, with the dissociation constant of 8.5 and 11.3 μmol/L, respectively. HparOBP15a had a certain binding affinity toward the sex pheromone components methyl L-isoleucinate and (-)-linalool, with the dissciation constant of 21.0 and 18.5 μmol/L, respectively. 【Conclusion】 HparOBP15a protein shows a broad odorant-binding spectrum and has a strong binding affinity toward dodecane, a volatile from host elm leaves. This protein thus may play an important role in locating host of H. parallela.

【Aim】 The objective of this research is to investigate the immunological functions of peptidoglycan recognition protein SC in the housefly, Musca domestica, in response to invading bacteria. 【Methods】 We knocked down the expression level of MdPGRP-SC  by feeding the newly-hatched larvae of M. domestica with Escherichia coli expressing double-strand RNA and then measured the interference effect with quantitative real-time PCR (qPCR). The treated larvae were fed with GFP-expressing E. coli, and then the tempo-spatial dynamics of these ingested bacteria was observed under fluorescent microscope. The hydrogen peroxide content and the expression profiles of antimicrobial peptide genes in the intestine of the larvae fed with dsRNA were tested by colorimetry and qPCR methods, respectively. 【Results】The qPCR results showed a significant decrease in the relative expression level of PGRP-SC in the interference group. After M. domestica  larvae fed with E. coli expressing GFP, a rapid fadeout of fluorescence in the MdPGRP-SC interference group was observed compared with the GFP control group. The hydrogen peroxide content in each group had no significant change, while the expression levels of all the four AMP genes were up-regulated dramatically in the gut of MdPGRP-SC depleted larvae. 【Conclusion】 MdPGRP-SC plays a role in regulating the sensitivity of intestinal immune reaction in housefly larvae.

【Aim】 Insect cuticular hydrocarbon profiles have been actively studied in insect chemotaxonomy. Liquid injection with solvent is commonly used technique for extraction and sample introduction. This study explored an easier and simpler extraction and sample introduction technique using solid injection. We discussed the feasibility of the technique in rapid identification of fruit flies. 【Methods】The cuticular hydrocarbon profiles of adult Bactrocera dorsalis (Hendel) were compared using thermal separation probe (TSP) (a solid phase injection device) and a liquid injection technique. Then the cuticular hydrocarbon profiles from head, thorax, abdomen, forewings, and legs of the fruit fly using solid injection were compared with those from the whole body extracts using liquid injection. Finally the cuticular profiles of the adult specimen preserved for various time periods were analyzed. 【Results】 The results showed that cuticular hydrocarbon components obtained from adult wing using solid injection (39 components) were higher than those obtained using liquid injection (36 components). The quantities of cuticular hydrocarbons from both wings and legs obtained using solid injection were 0.18-23.37 and 0.03-4.13 ng/μg, respectively. They were extremely significantly higher than those obtained using liquid injection (0.05-3.93 and 0.01-0.68 ng/μg from wings and legs, respectively) (P<0.01). The hydrocarbon amount from the wings was significantly higher than that from the legs (P<0.01). The detection sensitivity for cuticular hydrocarbon analysis using solid injection was 1.7-10.8 times as high as that obtained using liquid injection. The cuticular hydrocarbon composition of wings, legs, and thorax using solid injection was similar to that of whole body using liquid injection. Specimens preserved for 30 d in desiccator were not significantly different from fresh specimens in the composition and content of wing hydrocarbons (P>0.05). However, the compositions of wing hydrocarbons from specimens preserved for 30, 60 and 150 d were significantly different (P<0.05). 【Conclusion】 Solid injection technique can be used as an alternative method for cuticular hydrocarbon analysis of B. dorsalis, and adult wing is a good sampling part for the solid injection method. It is more sensitive than liquid injection method. The technique provides the technical basis for rapid identification of fruit flies during border inspection and quarantine.

【Aim】 To clarify the change in the bacterial community in larval midguts of the striped stem borer,  Chilo suppressalis  (Lepidoptera: Crambidae) after treatment with Bacillus thuringiensis insecticidal proteins. 【Methods】 Midguts were dissected from C. suppressalis  larvae that were collected from Beijing (BJ) and Fuzhou (FZ) of China and successively reared with artificial diets without Bt insecticidal proteins and with Bt insecticidal proteins (Cry1Ab, Cry1Ac and Cry1Ca), respectively. Degeneration gradient gel electrophoresis (DGGE) and Illumina MiSeq platform were employed to detect the bacterial community in these midguts and to compare its difference among different treatments (BJCK, BJCry1Ab,BJCry1Ac, FZCK and FZ1Ca) of the two populations. 【Results】 The DGGE profiles demonstrated that there was difference in bacterial abundance in larval midguts of C. suppressalis among different treatments. Analyses on DNA sequence of 16S rDNA libraries indicated that among the midgut bacteria  Enterococcus bacteria of Firmicutes was the most dominant, followed by bacteria of Lactobacillus  and Bacillus (Firmicutes), Proteobacteria, Chloroflexi, and Bacteroidetes. The proportions of the dominant Enterococcus bacteria in the larvae treated with Bt insecticidal proteins (BJCry1Ab, BJCry1Ac and FZ1Ca) were higher than those in the larvae without treatment with Bt (BJCK and FZCK), but the proportions of Lactobacillus bacteriawere lower in the larvae treated with Bt insecticidal proteins. The bacterial abundance also differed between BJCK and FZCK. 【Conclusion】 The results suggest that the bacterial abundance in larval midguts of  C. suppressalis  changes after treatment with Bt insecticidal proteins, which may be related to the difference in Bt insecticidal proteins, geographical sites and successive rearing time.

【Aim】 The objective of the present study is to investigate the in vitro and in vivo  inhibitory effects of castanospermine, a plant-derived chemical, on the soluble trehalase 1 (Harmtre1) from midgut tissues of the 5th instar larvae of Helicoverpa armigera  and the inhibition mechanism. 【Methods】 Crude Harmtre1 protein in the midgut tissues of the 5th instar larvae of  H. armigera  was isolated and purified by ion exchange chromatography and hydrophobic chromatography. Molecular weight of the obtained Harmtre1 protein was determined by gel filtration chromatography. Different concentrations of castanospermine were employed to determine the in vivo and in vitro inhibition rate and median inhibitory concentration (IC₅₀) on trehalase. The type of inhibition was determined with Lineweaver-Burk’s and Dixon’s mapping methods. 【Results】 The specific activity of enzyme, recovery rate, purification factor and the molecular weight of Harmtre1 was 2.022 U/mg, 67.57%, 23.84 and 67 kDa, respectively. The in vitro inhibition assay showed that the inhibition rates of Harmtre1 by 3.75, 7.5, 15 and 30 μmol/L of castanospermine were 42.00%, 50.30%, 58.32% and 67.33%, respectively. And the median inhibitory concentration (IC₅₀) was 7.32 μmol/L. According to the results of Lineweaver-Burk’s and Dixon’s mapping methods, castanospermine was an effective competitive inhibitor of Harmtre1 with an inhibitory constant (Ki) of 4.9 μmol/L. The in vivo inhibition assay indicated that the Harmtrel activity was markedly inhibited by 30, 15 and 7.5 μmol/L of castanospermine at 10 and 20 h after injection (P<0.05). Correspondingly, the content of lymphal Harmtre1 increased constantly with time after injection. Nevertheless, the concentration of lymphal glucose decreased significantly and the energy supply of H. armigera became disordered at 20 h after injection of castanospermine. 【Conclusion】 Castanospermine is an effective inhibitor of Harmtre1. Our results will supply a theoretical support to the development of effective insecticides in control of H. armigera in the future.

【Aim】 Trabala vishnou gigantina has become a serious leaf-eating pest of Hippophae rhamnoides in recent years, which feeds leaves of host plants at the larval stage, causing poor growth or even death of host plants. This study aims to determine the effects of temperature on the growth, development and reproduction of T. v. gigantina, and thereby to provide a foundation for the forecasting and scientific management of this pest. 【Methods】 Under a series of temperature gradients (19, 22, 25, 28 and 31℃), the developmental duration, food consumption, mating rate, oviposition, longevity of T. v.gigantina was investigated. 【Results】 Within the constant temperature ranging from 19 to 31℃, the duration of various developmental stages of T. v.gigantina shortened as temperature rose gradually. The development threshold temperatures of egg, larva, pupa, pre-oviposition and one complete generation were 9.24±0.45, 10.85±0.87, 14.56±0.85, 9.65±0.54, 10.48±0.52℃ and 341.22±9.54℃, respectively, and their effective accumulated temperatures were 1 285.64±17.65, 445.35±8.65, 13.34±1.25, 2 085.35±25.84 degree·days, respectively. The food consumption and mating rate were not affected significantly by temperature, and the number of eggs laid under temperatures of 22, 25 and 28℃ was higher than that under the other temperatures. The adult longevity was negatively correlated with temperature. 【Conclusion】 The temperature range of 22-28℃ is the most suitable for the growth, development and reproduction of T. v. gigantina. These findings provide valuable information for rational control of T. v. gigantina.

【Aim】 To explore the effects of host body size on potential reproductive capability of Sclerodermus guani, and so to provide data for understanding the quasi-social behavior evolution in parasitoids and mass production of Sclerodermus parasitoids in biological control of wood-boring beetle pests. 【Methods】 We exposed a larva of the small poplar longhorn beetle, Saperda populnea to a female adult of S. guani to oviposit each day until the wasp was dead. Number of eggs laid every day and offspring developmental performance without maternal care were analyzed in relation to host body weight at parasitism and oviposition periods (early, middle and late periods). 【Results】 The number of eggs laid by S. guani was affected not only by host body weight at parasitism, increasing in a quadratic function with host weight, but also by the oviposition period, decreasing distinctly from early to late periods. Offspring developmental performance of this parasitoid, as measured by the survival rate, number of emerged adults, adult body weight and sex ratio, was influenced by interactions between host body weight and oviposition period. Survival of offspring parasitoids slightly decreased with increasing host body weight for the eggs laid in the early period, but did not vary for the eggs laid in the middle and likely late periods. The number and sex ratio of emerged adults were not affected by host body weight for the eggs oviposited in the early and late periods, but the number of emerged wasps increased and sex ratio decreased with host body weight for the eggs laid in the middle period. Offspring female adult body weight increased with host body weight in a quadratic function for the eggs produced in the early oviposition period, but did not vary for the eggs laid in the middle period. 【Conclusion】 Host body size has a profound influence on the number of eggs laid and developmental performance of offspring parasitoids from the eggs laid in the early ovipositon period.

【Aim】 Different parasitoid species may parasitize a shared host in the same microhabitat. This study aims at understanding the intrinsic competition between parasitoids and providing data for evaluating the control effects of parasitoids in biological control. 【Methods】 We manipulated parasiting sequence and time interval of two solitary parasitoids, Meteorus pulchricornis (Wesmael) and Microplitis mediator (Haliday) that attacked larvae of the shared host  Mythimna separata (Walker). Survival of the two parasitoids in intrinsic competition and developmental parameters of M. pulchricornis were investigated and compared. 【Results】 M. pulchricornis offspring had higher survival rates than M. mediator in the competition under treatments with different combinations of parasitizing sequence and time intervals, reaching as high as 96.7% when parasitizing 24 h earlier. M. pulchricornis prolonged the larval duration when parasitizing hosts ahead of M. mediator compared to that when parasitizing alone (the control), but did not differ from the control when parasitizing after M. mediator. M. pulchricornisoffspring adults lived longer under each competition treatment than under the control. The adult size (measured by hind tibia length) of M. pulchricornisoffspring was significantly smaller under each competition treatment than under the control. 【Conclusion】 The results of this study suggest that M. pulchricornis outcompetes M. mediator in shared M. separata early instar larva hosts, but incurs negative impacts on its offspring development.

【Aim】 The objective of this research is to evaluate the selectivity and fitness of the two-spotted spider mite, Tetranychus urticae to different varieties of eggplant. 【Methods】 Using nine cultivars and one wild species of eggplant, the host selectivity was tested by selection experiment in field, while the effect of different varieties on colonization, population dynamics, developmental duration and fecundity of T. urticaewas investigated in laboratory. 【Results】 The results showed that T. urticae had the lowest selectivity to the wild species Solanum sisymbriifolium. All stages of T. urticae except for the egg stage could not survive on the wild species S. sisymbriifolium. Amongst the varieties of S. melongena, T. urticaeshowed the highest selectivity to Jingqie 6 and Riyouchangzhizhuangqingchangqie with a number of 195 and 183 individuals/plant, respectively, but showed the lowest selectivity to Bulita and Changzhusiqie. At 28 d after inoculation with 20 pairs of male and female adults of T. urticae, the number of mites on Zilongwang 4 (1 009 individuals/plant) was the highest, followed by Jingqie 6 (981 individuals/plant) and Grafted Jingqie 6 (909 individuals/plant). T. urticae had the shortest developmental duration on Jingqie 6 (9.31 d), but had the longest developmental duration on Changfeng 2 (11.08 d). Fecundity of female adults in the first 5 egg-laying days was higher on Jingqie 6, Jingqieheiba and Grafted Jingqie 6 (35.92, 33.20 and 31.34 eggs laid per female, respectively) with no significant difference among these three cultivars, while was lower on Zilongwang 4, Qiezhen 1, Bulita and Changfeng 2 (18.56, 19.24, 23.36 and 22.26 eggs laid per female, respectively) with no significant difference among these four cultivars. 【Conclusion】 Selectivity and fitness of the T. urticae  are high to the purple round type eggplant Jingqie 6, moderate to the purple long type eggplant Bulita, and low to the wild type eggplant Suanjieqie.

【Aim】 The Chinese honeybee (Apis cerana cerana) plays vital roles in pollination for agro-ecosystem and honey bee products. This study aims to investigate the population differentiation and genetic polymorphism among Apis cerana cerana populations across the Qinling-Daba Mountain Areas, and to explore possible factors contributing to genetic differentiation and difference of genetic polymorphism. 【Methods】 The genetic relationship was studied, and polymorphism was estimated among 979 colonies of A. c. cerana from 17 localities combined with two outgroups, A. c. cerana colonies from Changbai Mountain and Aba, based on eight microsatellite loci. 【Results】 The results showed that up to 95% of the variation was observed within sampling localities while less variation between localities. The genetic differentiation coefficient (Fst) among 17 localities ranged from 0.002 to 0.037, and the gene flow (Nm) was from 6.51 to 124.75, indicating that no population differentiation was detected. The mean expected heterozygosity (He), observed heterozygosity(Ho), number of alleles (Na), number of effective alleles (Ne), polymorphism information content (PIC) and Shannon’s information index (I )were 0.6877±0.1098, 0.6364±0.1367, 7.71±2.52, 3.7488±1.6201, 0.6418±0.1152 and 1.5026±0.3754, respectively, suggesting the abundant genetic polymorphism. The values of the genetic polymorphism indices including the expected heterozygosity, number of alleles, number of effective alleles and polymorphism information content were significantly lower in localities which underwent Chinese sacbrood virus pandemic recently than those in the virus uninfected areas. 【Conclusion】 In the context of the large population size and continuous distribution in Qinling-Daba Mountain Areas, there is no genetic differentiation among A. c. cerana populations across a distance of 650 km owing to a high level of gene flow. And the results also imply that the honeybee in Qinling-Daba Mountain Areas has rich genetic polymorphism. Significantly decreased polymorphism occurs in some localities that have undergone selective pressure from Chinese sacbrood virus prevalence.

【Aim】 The aim of this study is to investigate the species and the distribution of aquatic flies in the camel-living environment in Alashan of Inner Mongolia, Northern China. 【Methods】 Aquatic flies were surveyed by sweeping nets in the camel-living environment from May to September in 2014. The COI gene sequences of blood-feeding spcies identified were sequenced and analyzed. 【Results】 Totally 47 species of 41 genera in 21 families of aquatic dipteran insects were found, among which 16 species are newly recorded in Inner Mongolia, and 12 are blood-feeding species. Among all the sampled species, individuals of the three suborders Nematocera, Aristocera and Brachycera accounted for 49.3%, 43.5% and 7.2% of the total individuals sampled, respectively. The results of molecular analyses showed that the nucleotide sequence identities of the COI sequences of 12 blood-feeding species range from 75.9% to 97.3%, and significant differences exist between different families in the same order as well as between different genera in the same family. 【Conclusion】 This study revealed essentially the species composition of aquatic flies in the camel living area of Alasan in Inner Mongolia, particularly the blood-feeding species, which may serve as the basis for the subsequent identification of the vectors of camel onchocerciasis.

Insects have evolved an endogenous biological clock mechanism to synchronize behavioral, physiological and metabolic rhythms with environmental cues, which helps insects to use energy sources more efficiently, thereby conferring an adaptive advantage. The coordinated circadian regulation of behavior, physiology and metabolic cycles is crucial for insects to respond effectively to predictable physiological challenges. Circadian rhythms depend on gene expression to synchronize biochemical processes and metabolic fluxes with the external environment. Circadian clock genes play important roles in some crucial physiological processes such as central and peripheral biological clock mechanism, photoperiod signal transduction, photoperiod-mediated regulation of peripheral tissues, metabolism and immunity. Circadian clock genes are classified into three categories according to their roles: signal transduction-signal input genes, signal oscillation pacemakers and signal output genes. Circadian clock genes constitute complicated transcription-translation feedback loops through interactions with each other and regulate insect circadian and photoperiodic events. This review summarized the identification, classification and functions of circadian clock genes in insects, molecular mechanisms of their action, and the related research methods and challenges. The future research directions were also discussed. This review will provide reference information for further functional research and utilization of circadian clock genes in insects.