【Aim】 This study aims to explore the developmental expression pattern and functional analysis of bursicon genes  bursicon-α and  bursicon-β in Rhopalosiphum padi (Linnaeus). 【Methods】 In this study, the cDNA sequences encoding bursicon-α and bursicon-β were obtained from RNA-seq transcriptome sequencing of  R. padi . The expression patterns of  bursicon-α  and  bursicon-β are analyzed by real-time quantitative PCR and the functional analyses of bursicon-α and bursicon-β were carried out through RNA interference technology. 【Results】 The sequence analysis showed that the open reading frame (ORF) of bursicon-α from R. padi  is 480 bp in length, encoding a protein with 159 amino acid residues. The ORF of bursicon-β  is 417 bp in length, encoding a protein with 138 amino acid residues. The developmental expression patterns showed that bursicon-α and bursicon-β were ordinarily expressed during the whole developmental stage of  R. padi, and arrived at the highest expression level in the 1st instar nymph. The expression levels of these two genes in winged adult aphids were significantly higher than those in wingless adult aphids. RNA interference-mediated knockdown of bursicon-α and bursicon-β significantly inhibited the cuticular melanization of adult aphids. 【Conclusion】 These results revealed that bursicon plays an important role in the process of the cuticular melanization in R. padi, providing a foundation for further study for the physiological functions of bursicon in aphids.

【Aim】 c-Myc is an intensively studied transcription factor and also an important downstream target of Wnt/β-catenin signaling pathway. The objective of this research was to clone the c-myc cDNA from Helicoverpa armigera , to investigate the expression of Har-c-myc in mRNA level, and to prepare polyclonal antibody against Har-c-Myc. 【Methods】 Har-c-myc was cloned by RACE. The mRNA levels of Har-c-myc in the brain of non-diapause and diapause pupae were investigated by RT-PCR. Prokaryotic expression vector of  Har-c-myc was constructed and the recombinant protein was expressed in Escherichia coli . The purified recombinant protein was injected into a New Zealand rabbit to generate polyclonal antibody. The antibody titer was determined by ELISA. 【Results】 Har-c-myc cDNA was cloned successfully from H. armigera. The mRNA levels of Har-c-Myc were significantly lower in the brain of diapause pupae than in the brain of non-diapause pupae. Recombinant Har-c-Myc was successfully expressed in E. coli and purified by Ni-NTA agarose column. The titer of the antibody against Har-c-Myc was estimated by ELISA as high as 1:125 000. 【Conclusion】 The expression of Har-c-myc is down-regulated in the brain of diapause pupae. Antibody against Har-c-Myc was obtained. This study lays a foundation for further investigating the function of Wnt/β-catenin in the diapause of H. armigera.

【Aim】 Doublesex (dsx) is a key gene involved in the sex determination system, which controls sex determination in the germ line and soma of insects. This study aims to obtain the full-length cDNA sequence of  dsx  from major malaria mosquito  Anopheles gambiae , to reveal the sex-specific differences in splicing patterns of dsx pre-mRNA, and to determine the expression profiles of  dsx  in different developmental stages. 【Methods】 The full-length cDNA of doublesex (Angdsx) were obtained from A. gambiae using RT-PCR and RACE methods. The motif prediction, multiple alignments of amino acid sequences and-phylogenetic analysis were conducted by corresponding bioinformatics softwares. RT-PCR analysis was performed to analyze its sex-specific and development-specific expression profiles. 【Results】 The full-length cDNA sequences of Angdsx  were cloned from female and male adults of A. gambiae, and named Angdsx^M (GenBank accession no. KM978938) and Angdsx^F (GenBank accession no. KM978937), respectively. Angdsx  covers an 80 kb genome region on chromosome 2R. Angdsx^F and Angdsx^M are 4 874 nt and 3 183 nt in length, encoding 265 and 633 amino acids, respectively. Besides the conserved motifs including TRA/TRA-2 binding site, dsx  repeat elements (dsx REs), arginine-serine rich protein, purine-rich enhancer and RNA-binding proteins target sequences, the GT repeat motifs were also indentified in Angdsx by meme program. Compared with Angdsx^M, Angdsx^F contains an extra female specific exon. RT-qPCR analysis displayed that the expression level of Angdsx^M was higher in 0-2 h  embryo and then declined, but increased from 12-24 h embryo again, while that of Angdsx^F raised from 6-8 h. 【Conclusion】 The full-length Angdsx gene was isolated and identified from A. gambiae, which shows conservation of functional domains and sex-specific splicing. This study contributes to understanding the sex differentiation in mosquitoes and may facilitate the application of transgenic mosquitoes based release of insects carrying a dominant lethal (RIDL) technology on vector control.

【Aim】 The geomagnetic orientation is one of the important mechanisms for the flight orientation of migratory insects in their long distance migration. In this study, the macropterous and brachypterous female and male adults of the brown planthopper (BPH), Nilaparvata lugens were selected to systemically study the magnetic materials harbored in their bodies. 【Methods】 The superconducting quantum interference device (SQID) (model: MPMS-7) was used to detect the existence of magnetic materials in the macropterous and brachypterous female and male adults of BPH, and the distribution of magnetic materials in the four types of adults was observed using the ultrathin paraffin sections (UPS) with Prussian blue staining (PBS) under the transmission electron microscope (TEM) (model: JEM-2100). The atomic emission spectroscopy (AES) was used for the quantitative analysis and comparison of the magnetic materials in the four types of adults. 【Results】 The SQID detection found that the hysteresis curves were obviously closing only in the abdomen of the macropterous and brachypterous female and male adults of N. lugens, indicating that magnetic materials harbored in the abdomen of adults. Prussian blue precipitate also mainly existed in the abdomen through the observation under TEM, indicating that the detected magnetic materials are ferromagnetic substance. There were significant differences in the contents of magnetic materials between the macropterous and brachypterous adults and between the males and females through the AES detection. For adults of the same gender, the Fe ion content in the macropterous individuals was significantly higher than that in the brachypterous individuals. And for the same wing-form, the Fe ion content in the male adults was significantly higher than that in the female adults. 【Conclusion】 Fe magnetic materials generally exist in the abdomen of macropterous and brachypterous female and male adults of N. lugens, and their contents are significanly different between the macropterous and brachypterous adults and between the males and females.

【Aim】 In this study, the potential side effects of the sublethal doses of imidacloprid on the midgut bacteria of the worker bees of Apis mellifera ligustica was investigated under laboratory conditions so as to provide a theoretical basis for the biosafety assessment of pesticides. 【Methods】 Newly emerged bees were fed on syrups with different sublethal doses of imidacloprid (0.005 mg/L, 0.015 mg/L and 0.045 mg/L) and pure sugar syrup with 0.3% acetone, and samples were collected after 3, 6, 9, 12 and 15 d, respectively. The population structure of bacteria in the midgut of honeybees in the four treatment groups was analyzed using next-generation sequencing after the genomic DNA was gained from intestinal bacteria. 【Results】 The results of sequence analysis showed that the midgut bacteria in A. mellifera ligustica mainly belong to Proteobacteria and Firmicutes. The composition of dominant midgut bacteria and the richness estimators in the same period were analyzed for statistical significance among the four treatments by performing a T-test, and no significant differences were observed (P>0.05). 【Conclusion】 The results suggest that the sublethal doses of imidacloprid does not induce significant changes in the composition of the honeybee gut bacterial community under laboratory conditions.

【Aim】The cotton aphid,  Aphis gossypii Glover, is one of the most injurious pests of fruits, vegetables and ornamental plants worldwide, both outdoor and indoor. This insect, which feeds from plant sap, produces honeydew and transmits plant viruses, and causes quantitative and qualitative damages in plants. For controlling this pest in greenhouse, plant essential oils are used as an alternative to chemical insecticides. So in this research the fumigant toxicity of Carum copticum L. (Apiaceae) essential oil against A. gossypii adults was studied. 【Methods】 Dry ground seeds of C. copticum were subjected to hydrodistillation using a modified Clevenger-type apparatus. All bioassay tests were conducted at 27± 2℃, 65%±5% RH and a photoperiod of 16L:8D. This research was performed with a completely random design with 6 treatments (5 different concentrations of essential oils plus the control). Each concentration included 3 replicates and each replicate consisted of 20 adult pests. 【Results】 The results showed that the C. copticum essential oil caused significant mortality of adults 24 hours after exposure. The LC₅₀ value of the essential oil against  A. gossypii adults was 1.21 μL/L air. The mortality percentage of  A. gossypii showed higher sensitivity to application of the essential oil. The LT₅₀ value of this essential oil estimated for A. gossypii at the concentration of 1.21 μL/L air was 11.79 h. The fumigant toxicity of this essential oil had an ordered relationship with the concentration and time exposure. Results of GC/MS constituents showed that the essential oil consisted of 18 chemical compounds and most importantly included thymol (50.07%), gamaterpinene (23.99%), and p-cymene (22.90%). 【Conclusion】 The results suggest that  C. copticum essential oil has appropriate insecticidal effects on cotton aphids, which may have a promising potential to be used in the integrated pest management programs of pest insects in greenhouses.

【Aim】 This study aims to explore the effects of temperature on the population growth of Periphyllus koelreuteriae (Takahashi). 【Methods】 We investigated the developmental duration, survivorship, and fecundity of P. koelreuteriae in the laboratory under the conditions of 12, 15, 18, 23, 26 and 29(±1)℃, RH 60%±7% and a photoperiod of 15L: 9D, and constructed life tables of their laboratory populations. 【Results】 The results showed that no nymph hatched at 29℃, and the developmental duration of egg and nymph decreased with the temperature increasing from 12℃ to 23℃. The longest duration of egg and nymph was 13.97 d and 21.94 d at 12℃, and the shortest was 5.86 d and 7.34 d at 23℃, respectively. The relationship between the developmental rate and temperature could be simulated by the Logistic model. Adult lifespan and pre-reproduction period decreased as the temperature increased, and the highest fecundity per female was 107.06 and 120.23 at 18℃ and 23℃, respectively, while the lowest was 63.16 at 26℃. Analysis of life table parameters showed that the net reproductive rate (R₀) and the intrinsic rate of increase (r_m) increased as the temperature increased, with the highest values of both found at 23℃. Relationship between the intrinsic rate of increase (r_m) and temperature (T) could be described by the equation: r_m=-0.0018T²+0.075T-0.5945 (R²=0.9419, P=0.0481). 【Conclusion】Temperature has great effects on the development and reproduction of P. koelreuteriae, and the most suitable temperature range for this pest is from 18℃ to 23℃, during which there is higher intrinsic rate of increase.

【Aim】 Diurnal temperature fluctuation has very important influences on the development, survival, reproduction and longevity of insects. Previous researches have focused on constant temperature. The constant temperature design is unable to reflect the diurnal temperature fluctuation in the nature, and can not quantitatively analyze the difference between fluctuating and constant temperature. 【Methods】 We investigated the effects of different diurnal alternating temperature fluctuations with the same mean temperature (25±0℃, 25±2℃, 25±4℃, 25±6℃, 25±8℃, 25±10℃, 25±12℃) on life history parameters of different developmental stages in a worldwide cruciferous pest, the diamondback moth (DBM), Plutella xylostella. 【Results】 The results showed that different temperature fluctuations had significant effects on the development, survival, longevity and reproduction of  P. xylostella at different developmental stages. The life history parameters of P. xylostella at 25±2℃, 25±4℃ and 25±6℃ were similar with those at the constant temperature (25℃), but the fluctuating temperatures of 25±10℃ and 25±12℃ had significantly negative effects on the life history parameters of P. xylostella . 【Conclusion】 We found that wide diurnal temperature fluctuations have significant effects on P. xylostella, and suitable night low temperatures offset the disadvantage effects of daily high temperature stress on P. xylostella. Diurnal temperature fluctuation, as an important determinant influence factor of insects, should be considered into the predicting model of insect population dynamics, which will improve the accuracy of insect forecast in the field and really reflect the effects of diurnal temperature fluctuations on insect ecology.

【Aim】 Agriphila aeneociliella (Eversmann) has become an important pest in China in recent years, causing sprout deficiency by the larval feeding on the wheat stem, and has a potential threat to wheat. This study seeks to determine the effect of temperature and foods on the growth and development of A. aeneociliella larvae so as to provide a basis for its population monitoring and management. 【Methods】 Under laboratory conditions (photoperiod 14L:10D, RH 70%±15%), the developmental duration and survival rate of A. aeneociliella larvae reared on wheat at a series of temperatures were investigated, and the developmental threshold temperature and effective accumulated temperature were analyzed. The developmental duration and survival rate of A. aeneociliella larvae reared on wheat, maize and artificial diet were monitored at 25±1℃ with a 14L:10D photoperiod in the laboratory. 【Results】 The results showed that the temperature had significant effects on the development of A. aeneociliella. Within the constant temperature ranging from 13 to 29℃, the developmental duration of each stage of A. aeneociliella larvae shortened as the temperature rose gradually. There was no significant difference in the survival rate of larvae at the constant temperatures ranging from 13 to 29℃. However, under the constant temperature of 33℃, the development was suppressed obviously and the larvae died before completing a whole life span. The developmental duration of each instar of larvae (especially 1st-3rd instar larvae) feeding on different diets had significant difference, with the order of that feeding on wheat<that feeding on maize<that feeding on artificial feed. The developmental duration of the 4th-6th instar larvae feeding on wheat and maize had no significant difference, but was significantly lower than that feeding on artificial feed. 【Conclusion】A. aeneociliella has strong temperature adaptability and its developmental duration is significantly influenced by temperature changes. In the current occurrence area, wheat is the most suitable host and A. aeneociliella feeding on maize can also complete the larval growth and development in the laboratory. This study provides theoretical data for estimating the potential occurrence area in China and technical support for forecasting and comprehensively control the population dynamics of A. aeneociliella in the future.

【Aim】 Cannibalism could facilitate the infection of certain pathogens that can be transmitted by feeding on infected conspecifics. This may have potential applications in the control of pests by entomopathogens. Our study aims to explore the relation between cannibalism and age and nutrition in larvae of the cotton bollworm, Helicoverpa armigera. 【Methods】 We estimated the incidence of cannibalism of H. armigera larvae by feeding different concentrations of sodium to a laboratory population and a wild population, and examined whether dietary sodium had any effects on the cannibalism. 【Results】 The survival rates of the larvae of H. armigera were the lowest when the tests were initiated at the beginning of the 3rd and 4th instars, statistically significantly increased when the experiments were carried out at the beginning of the 5th instar, and further raised when the experiments were performed at the beginning of the 6th instar. Moreover, the survival rates of the larvae fed on normal diet prior to experiment were the highest, and slightly but distinctly decreased when the larvae fed on sodium-deficient diet. In addition, the pupation rates of the larvae were similar, irrespective of whether the larvae fed on normal or sodium-deficient diets, and whether the experiments initiated at the beginning of the 3rd, 4th, 5th or 6th instar. 【Conclusion】 The results demonstrate that for H. armigera  larvae cannibalism highly occurs in the 4th and 5th instars rather than the 3rd and 6th instars, and to some extent, sodium deficiency enhances cannibalism. This study provides a basis for further work in this field.

【Aim】 The camellia weevil, Curculio chinensis Chevrolat, is an important pest of the fruits of oil tea camellia ( Camellia spp.) in China. Its infestation often leads to a lot of fruit drop from the camellia plants. For the study of the biology and ecology of weevil, it is very important to be able to determine the instar of the larva. However, in the case of xylophagous insects, this is particularly difficult. This study aims to clarify the number of larval instars of this pest, to identify the ranges of the instars in our study area and to design a reliable method for determining the instars of an individual larva. 【Methods】 In 2014, 1 253 larvae of  C. chinensis were collected from Camellia meiocarpa, and the head capsule width and length, and the mandible width of each larva were measured. Frequency distribution of the data was fitted using multiple peak fit (in Origin 9.0), the separation points of adjacent instars were determined by the intersection points of the normal curve, and then the means, range, growth ratio, and misclassification probability for all larval instars of the weevil were calculated. For the determination of the instar number, the Dyar’s rule was also used. 【Results】 Multiple peak fit of the frequency distribution of the head capsule data resulted in 5 normal and distinct peaks (P＜0.01), representing the five instars (1st-5th instars). The misclassification probability of the 3rd instar larva was 6.04%, 7.03% and 6.51% for the head capsule width, head capsule length and mandible width, respectively. The misclassification probability of the other instars was less than 5%, suggesting that the 3 morphological measurements could be used to identify the weevil’s larval instars, of which the head capsule width is the most important one. The growth ratios of the instars were almost constant, being 1.41-1.54, 1.43-1.61 and 1.44-1.64 for head capsule width, head capsule length and mandible width, respectively. The positive correlation between the natural logarithm of the measurements and the larval instars showed that the larval growth of the weevil followed Dyar’s rule of a geometrical growth pattern. 【Conclusion】 The camellia weevil has 5 instars instead of the 4 instars found in the previous research. Multiple peak fit is useful to determine the instar number of xylophagous insects or field collected larvae. Especially, it provides an effective method to identify the number of larval instars despite the overlap of adjacent instars.

The paired antennal lobe is the primary olfactory center of insect brain, linked by antennal nerves to the antennae. The antennal lobe is mainly composed of olfactory receptor neurons, local interneurons, projection neurons and centrifugal neurons. Each of these categories of neurons is morphologically categorized into several types. The types associate with their functions and show species-specificity. The antennal lobe neurons are organized into neuropil with a large number of glomeruli, which house dense synaptic contacts and are arranged in one or two layers at the periphery of the AL. In a given antennal lobe, the number, size and position of glomeruli are constant and almost each glomerulus can be identified and named. However, the number, size and position of glomeruli show species-, sex- and caste-specificity. Such organization of the antennal lobe is associated with species- , sex- and caste-specific olfactory behavior of insects.

Autophagy, a process of the cells to achieve the intracellular material recycling through the self-degradation of lysosome, plays an important role in insect cellular differentiation and individual development. Lepidopteran insects, belonging to the complete metamorphosis insects, could actualize metamorphosis reconstruction process by autophagy and apoptosis, and are the model organisms for studying the mechanisms of autophagy. Atg8 of lepidopteran insects, which is a homolog of microtubule associated protein 1 light chain 3 of mammals and the core protein family of autophagy-related protein, plays important roles in the formation of autophagosomes, the extension of membrane, the identification of specific substances, and so on. In this article we reviewed the Atg8 effect in autophagy pathway, the characterization of Atg8, the expression and distribution of Atg8, and the relationship between Atg8-PE/Atg8 and autophagic activity in lepidopteran insects. Atg8-PE is one of the ubiquitin-like conjugation systems, and plays a key role in autophagy. Sequence analysis showed that the structure of Atg8 in lepidopteran species is very similar to the homologous proteins of other eukaryotes, and especially its amino acid sequence is highly consistent with the homologous proteins of other insect species, revealing the highly conservative property of Atg8. During the different developmental stages of lepidopteran species, the expression and distribution of Atg8 are various in organs such as the midgut, salivary glands, ovary, fat body and silk glands, and different in nucleus and cytoplasm. The shuttling of Atg8 between nucleus and cytoplasm might exist in some cells at the pre-pupal stage. Through detecting the expression level of Atg8-PE or the change of Atg8 abundance inside the cell, we can evaluate the process of autophagy.

As important disease vectors, most mosquitoes need to take sugar meals in their adult stage, and they show distinct preferences for different constituents of sugar meals. Meanwhile, specific circadian rhythms are observed in their sugar-feeding behaviors. Under field conditions, mosquitoes show preferences for different flowering plants and seed pods, which in turn have significant effects on their survival, longevity and fecundity. The volatile organic compounds produced by nectar plants play important roles in directing mosquitoes’ location of their sugar hosts, and several electrophysiological active volatile compounds have been identified. Application of attractive toxic sugar baits shows a significant effect on controlling different kinds of mosquitoes. Besides, the sugar-feeding behaviors of vectors have been applied in controlling other disease vectors and detection of vector-borne pathogens successfully. Development of mosquitospecific bait traps on the basis of volatile compounds produced by nectar plants will be promising in decreasing the risk of population of vector-born diseases. In this article, we reviewed the sugar-feeding behavior of adult mosquitoes, the research about preferred host plants of mosquitoes and the mosquito management methods by means of mosquito sugar feeding behavior.