【Aim】 Drosophila is one of holometabolous insects. It undergoes the process of dissociation of old tissues and remodeling of adult tissues at the pupal stage. The objective of this study is to investigate whether hindgut enterocytes of Drosophila migrate into the midgut during metamorphosis by G-TRACE (Gal4 technique for real-time and clonal expression) which is a new genetic technique. 【Methods】 engrailed-Gal4 (en-Gal4) line and lineage-tracing line (G-TRACE) of Drosophila melanogaster were hybridized, and tub-gal80^ts was introduced to temporally control Gal4 activity. The cell lineage was traced at the larval and pupal stages, respectively. For larval stage tracing, eggs were cultured at 30℃ after egg-laying by the parental generation, and the mid 3rd instar larvae were shifted to 18℃. The adult guts were detected within 1 d after eclosion. For pupal stage tracing, eggs were cultured at 18℃ after egg-laying by the parental generation, pupae were shifted to 30℃ at different stages, and adult guts were detected after eclosion. 【Results】 In larval stage tracing of Drosophila, green intestinal cells appeared in the posterior section of midgut, which is adjacent to the hindgut-midgut boundary and Malpighian tubules. In pupal stage tracing of Drosophila, green intestinal cells appeared at different sections in the midgut and Malpighian tubules, and engrailed gene was expressed in Drosophila intestine at the pupal stage. 【Conclusion】 These results suggest that during pupa formation, part of the hindgut cells migrate into the midgut or Malpighian tubules and are involved in the reformation of adult midgut or Malpighian tubules. This study is of important significance in understanding the mechanisms of insect organ remodeling during metamorphosis.

【Aim】 Estradiol (E₂), an estrogen hormone, regulates the growth and reproduction through estrogen receptors (ERs) in vertebrates. There is no ER in insects, but studies showed that some insects can respond to E₂. In this study, the possible regulatory mechanisms of the expression of vitellogenin gene by E₂ was elucidated in the silkworm, Bombyx mori, after confirming that E₂ influenced the expression of BmVg in female larvae of the silkworm. 【Methods】 The expression level of BmVg was detected in the fat body of female larvae (60 h after mounting) of B. mori after in vitro treatment with different concentrations of E₂ (0.001, 0.05, 0.5, 5 and 50 nmol/L) by qRT-PCR, and the response of the silkworm to E₂ was analyzed. The ecdysone receptor gene of B. mori (BmEcRB1) was cloned and its prokaryotic expression vector was constructed. The BmEcRB1 protein was purified and incubated with E₂ in vitro, and the binding characteristics of E₂ to BmEcRB1 were assayed by microscale thermophoresis (MST). 【Results】 Different concentrations of E₂ significantly inhibited the expression of BmVg of female larvae of B. mori after in vitro culture, and the inhibitory effect was more obvious with the increase of E₂ concentration. MST results showed that E₂ had a certain affinity with BmEcRB1, with the dissociation constant (Kd) value of 77.8±22 μmol/L. 【Conclusion】 The results suggest that E₂ inhibits the expression of BmVg in the silkworm through competition with ecdysone to bind BmEcRB1.

 【Aim】 Odorant binding proteins (OBPs) contribute to the remarkable sensitivity of insect olfactory system and play an important role in aphid alarm pheromone (E)-β-farnesene (EBF) communication. The turnip aphid, Lipaphis erysimi (Kaltenbach) is the major pest of cruciferous crops. To reduce pesticide application in vegetable fields, EBF appears to hold strong potential for aphid control. However, few studies about L. erysimi to EBF are known so far. 【Methods】 Two putative OBP genes, LeryOBP3 and LeryOBP7 encoding proteins with high affinity to EBF were cloned by PCR and RACE and characterized from L. erysimi, and their expression profiles at different developmental stages and in different tissues of wingless adults of L. erysimi were determined by RT-qPCR. 【Results】 The two genes cloned here, LeryOBP3 (GenBank no.: KJ703012) and LeryOBP7 (GenBank no.: KJ703013) share high amino acid sequence identities (94% and 88%, respectively) with ApisOBP3 and ApisOBP7, which encode proteins with affinity to EBF in Acyrthosiphum pisum (Harris). The full length of open reading frames of LeryOBP3 and LeryOBP7 are 357 and 468 bp, encoding 118 and 155 amino acids, respectively. Developmental expression profiles showed that the obvious expression peaks of LeryOBP3 and LeryOBP7 appeared at the adult stage, and tissue expression profiles showed that LeryOBP3 was expressed strongly in legs of adults while LeryOBP7 in adult antennae. 【Conclusion】 These results suggest that LeryOBP7 in the antennae might be responsible for the response of L. erysimi to EBF.

【Aim】 Trehalose-6-phosphate synthase (TPS) is one of key enzymes in the trehalose synthesis pathway. This study aims to clone the TPS gene from Galeruca daurica and to analyze its expression levels in response to temperature stress so as to investigate the molecular regulation mechanisms of TPS in temperature tolerance in G. daurica. 【Methods】 The full-length cDNA of the TPS gene was cloned from G. daurica by rapid amplification of cDNA ends (RACE), and its sequence was subjected to bioinformatics analysis. The expression profiles of the TPS gene in the 2nd instar larvae of G. daurica at different temperatures were detected by real-time quantitative PCR. 【Results】 A TPS gene was cloned from G. daurica, and named GdTPS (GenBank accession no.: KY460114), which is 2 706 bp in length with an open reading frame (ORF) of 2 496 bp, encoding a protein of 831 amino acids with the predicted molecular weight of 94.05 kD and pI of 6.82. The encoded protein contains three potential N-glycosylation sites, without signal peptide and transmembrane domain. GdTPS has two conserved domains, shares higher amino acid sequence identity with TPSs of other insect species and has the highest amino acid sequence identity (88%) with TPS from Leptinotarsa decemlineata. Real-time quantitative PCR results showed that when the stress temperature was lower than 25℃ (the control), the expression level of GdTPS increased as the temperature decreased, and reached the peak at -10℃. However, when the stress temperature was higher than 25℃, its expression level increased as the temperature increased, and reached the peak at 40℃.【Conclusion】 The expression of GdTPS in G. daurica larvae is up-regulated significantly in response to low and high temperaturestresses. The results provide a foundation for the functional research of TPS in the regulation of temperature stress in insects.

【Aim】 This study aims to explore the expression pattern of Musca domestica sirt1 gene (Mdsirt1) under various stress conditions. 【Methods】 The sequence of Mdsirt1 gene was cloned by PCR from the 2nd instar larvae of Musca domestica and subjected to bioinformatics analysis. The expression profiles of Mdsirt1 in different developmental stages (egg, 1st instar larva, 2nd instar larva, 3rd instar larva, pupa and adult), various tissues of the 2nd instar larvae (cuticle, gut, fat body and hemocyte), and the 2nd instar larvae under stresses (challenged by bacteria, heat shock and CdCl₂ stimulation) were investigated via quantitative real-time PCR (qRT-PCR). RNAi was employed to knock down the expression of Mdsirt1 in M. domestica larvae by microinjection with dsRNA, and then the resistance of larvae to bacteria and oxidative stress was detected. 【Results】 The deduced protein encoded by Mdsirt1 contains a predicted SIR2 domain, and shows 66% sequence identity with SIR2 from Stomoxys calcitrans. qRT-PCR results showed that Mdsirt1 was mainly transcribed in the pupal stage and fat body of the 2nd instar larvae of M. domestica. Enhanced expression of Mdsirt1 was observed in response to Escherichia coli and Staphylococcus aureus challenge for 3 and 6 h, respectively. The expression of Mdsirt1 was significantly induced by heat shock of 42℃ for 30 min, and cadmium stimulation (exposure to 30 mmol/L CdCl₂) for 48 h. The survival rate observed in larvae treated with dsRNA of Mdsirt1 under bacterial challenge (E. coli∶S. aureus=1∶1) was 1.47-fold lower than that treated with dsRNA of GFP. RNAi-mediated knockdown of Mdsirt1 led to oxidative stress, and caused rapid increase of 1.58- and 1.59-fold in the reactive oxygen species (ROS) level and malondialdehyde (MDA) content, respectively. 【Conclusion】 Mdsirt1 is involved in immunity and stress resistance in M. domestica larvae.

【Aim】 RBP1 is an important splicing factor involved in alternative splicing of the pre-mRNA of Drosophila melanogaster sex-determining gene dsx. This study aims to clone the nucleotide sequence of RBP1 gene AmRBP1 of Apis mellifera, and to analyze the domains of its amino acid sequence and its mRNA expression profiles in different developmental stages of embryo and larva, so as to provide a basis for studying its function in honeybee sex determination. 【Methods】 Several transcriptome sequences of AmRBP1 were obtained by homology search with Drosophila melanogaster rbp1 based on the predicted gene database and the transcriptome database of A. mellifera, and PCR primers were designed based on these transcriptome sequences. Then, AmRBP1 was cloned and its nucleotide and amino acid sequences were analyzed with bioinformatic software. The expression profiles of AmRBP1 in different developmental stages of embryo and larva of A. mellifera were assayed by semi-quantitative RT-PCR. 【Results】 The results showed that AmRBP1 has three alternative splicing variants named AmRBP1-R1 (GenBank accession number:KY404154), AmRBP1-R2 (GenBank accession number: KY404155) and AmRBP1-R3 (GenBank accession number: KY404156), respectively, whose mRNA sequences are 696, 790 and 771 nt in length, encoding proteins of 130, 166 and 162 aa, respectively. Protein domain prediction indicated that all of the three isoforms contain the same domains, with an amino terminal RRM domain and a carboxyl terminal RS domain. Homology analysis showed that AmRBP1 has 96.97%, 94.20%, 84.85%, 81.48%, 80.28%, 78.15% and 69.23% amino acid sequence identity with RBP1 proteins of Nasonia vitripennis, Solenopsis invicta, Aedes aegypti, D. melanogaster, Bombyx mori, Musca domestica and Anopheles sinensis, respectively. The semi-quantitative RT-PCR results showed that AmRBP1-R1-3 were expressed in various developmental stages of embryo and larva, with no obvious sex difference. 【Conclusion】AmRBP1 may be a member of SR family splicing factors with no obvious sex difference, and whether it is involved in the sex-specific splicing of doublesex (dsx) pre-mRNA needs further research.

【Aim】 Ubiquitination is an important reversible post-translational modification, which is involved in cell cycle, signal transduction, transcriptional regulation and immune response. However, the function of ubiquitin-proteasome system in virus transmission by insect vectors remains unknown. This study aims to explore the interactions between the ubiquitin-proteasome system of whitefly Bemisia tabaci and Tomato yellow leaf curl virus (TYLCV). 【Methods】 The expression levels of ubiquitin and proteasome subunit genes in Bemisia tabaci adults feeding on TYLCV-infected and uninfected tomato plants were detected by RT-qPCR. Changes in the contents of free and conjugated ubiquitin proteins in B. tabaci adults after TYLCV infection were detected by Western blotting. After the ubiquitin-proteasome system was disrupted with specific inhibitors or dsRNA injection, changes in the TYLCV content in B. tabaci adults were detected by RT-qPCR. 【Results】 Carrying TYLCV did not lead to significant change in the expression levels of ubiquitin and 26S proteasome subunit 4, 6B and β genes in B. tabaci adults, and had no influence on the contents of free ubiquitin and conjugated ubiquitin proteins and their ratio, suggesting that TYCLV has no effect on the ubiquitin-proteasome system of the whitefly. However, disrupting ubiquitin-proteasome system by specific inhibitors Bortezomib or MG132 or silencing Rpn11 by RNAi led to significant increase in the TYLCV content in B. tabaci adults. 【Conclusion】 Ubiquitin-proteasome system negatively regulates the TYLCV content in B. tabaci. Ubiquitin-proteasome system might help the whitefly to counteract the negative influence from TYLCV through degrading the virus directly or activating immune response.

【Aim】 The present study was carried out to evaluate the insecticidal, protectant and repellent potentials of hexane, acetone and methanol extracts of leaves of Ocimum canum Sims (Lamiaceae) against Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae). 【Methods】 Cowpea and soybean were coated with extracts from O.canum at dosages of  1 and 5 g/kg grains and commercial neem seed oil (NSO) as a reference at the same dosages. Adult mortality of C. maculatus was assessed during a period of seven days, one day interval. Ovicidal and larvicidal toxicity was tested by treating freshly laid eggs and larvae at different immature stages of C. maculatus. Grain damage and weight loss were assessed after a storage period of four months. Repellency effects were detected in choice test using a linear olfactometer. 【Results】 Extracts had the same toxicity to C. maculatus adults and proved to be more toxic than the commercial NSO in treated cowpea. Hexane, acetone and methanol extracts caused 54.2%±3.9%, 62.9%±4.8% and 60.3%±4.5% adult mortality, respectively,within seven days of exposure to the dosage of 5 g/kg cowpea grain. Moreover, extracts evoked stronger repellency effects compared with the tested standard insecticide, irrespective of grain species. The products were the most toxic to eggs, and more toxic to 1st and 2nd instar larvae than to other developmental stages. Hexane extract was the most effective against the 2nd instar larvae (81.0%±5.3% mortality), while acetone extract (92.5%±7.5% mortality) and methanol extract (62.0%±15.7% mortality) were the most effective against the 1st instar larvae. Acetone extract had a similar toxicity with the tested standard insecticide against the 1st and 2nd instar larvae and was superior against the pupae. Cowpea grain damage and weight loss were reduced by more than three- and two-fold, respectively, after four months of storage. 【Conclusion】 The outcome of this study indicates the potential of extracts from O. canum as repellent and insecticide against C. maculatus, and because of its availability the plant is strongly recommended to be used in pest management strategies in Cameroon.

【Aim】 To explore the effects of propionic and butyric acids on the oviposition preference of Drosophila melanogaster, and to provide an insight into its biological significance. 【Methods】 The 2-choice apparatus was employed to assess the oviposition selection of D. melanogaster female adults. The flies with the acid-sensing gustatory receptors eliminated or the olfactory antennae surgically removed were used to investigate the oviposition-associated sensory system. The developmental duration and survival rate of the fruit fly were utilized to evaluate the biological significance of oviposition avoidance of D. melanogaster to propionic acid. 【Results】 D. melanogaster female adults displayed an oviposition avoidance to propionic and butyric acids in a dosage-ependent manner. The oviposition avoidance of IR64a and IR76b mutants to 0.5% propionic acid was completely impaired with the oviposition index of -0.07 and -0.17, respectively. The female adults repelled human feces to oviposit with the oviposition index of -0.7--0.9, which may be explained by a balanced decision to the attractiveness to acetic acid and the avoidance to propionic acid. IR64a and IR76b mutants showed less oviposition avoidance to human feces with the oviposition index of -0.49 and -0.38, respectively. Propionic acid dramatically delayed the developmental duration of their progeny and reduced the survival rate in a dosage-dependent manner, and 2% propionic acid caused death of larvae. 【Conclusion】 D. melanogaster female adults repel to lay eggs on food with propionic acid through the olfactory system, and this behavior promotes the development of D. melanogaster larvae and boosts the survival rate of their offspring.

【Aim】 Western flower thrips, Frankliniella occidentalis, is a worldwide invasive pest causing devastating damage on crops. Now it becomes a big threat to vegetable and ornamental industry in China. In order to establish the basis of using aggregation pheromone to monitor and control this pest, the mating activity, the female-male interaction and release rhythm of aggregation pheromoneofmaleadultsof F. occidentalis during photophase were investigated in this study. 【Methods】 The mating behavior of F. occidentalis adults was tested using single pair mating and group mating methods, the female-male interactions were observed under video system, and the release rhythms of aggregation pheromone in male adults were analyzed at four time (the 1st, 4th, 8th and 12th hour) of photophase using solid phase micro-extraction and gas chromatography-mass spectrometry. 【Results】 The mating percentages, mating duration, femalemale interaction repeats and male harassment repeats of F. occidentalis adults at the four time of photophase were not significantly different, suggesting that the corresponding behaviors are arrhythmic during photophase. The release rhythms of the attractive aggregation pheromone component neryl (S)-2-methylbutanoate were in accordance with the behavior pattern, without significant difference at the four time of photophase. However, the release rates of unattractive aggregation pheromone component (R)-lavandulyl acetate were significantly different at the four time of photophase. 【Conclusion】 The study confirmed that the mating activity, female-male interaction and the release of the attractive aggregation pheromone component neryl (S)-2-methylbutanoate of F. occidentalis adults are arrhythmic during photophase. These results provide a theoretical basis for understanding the behavioral function of aggregation pheromone compounds and a guide for population monitoring and pest control of thrips using aggregation pheromones in the field.
 

【Aim】 Male adults of both Frankliniella occidentalis and F. intonsa can release aggregation pheromones, which have two major compounds (R)-lavandulyl acetate and neryl (S)-2-methylbutanoate but in different ratios, and attract both female and male adults. Given the overlap in pheromone components and similar niches between the two species, we hypothesize that aggregation pheromones might play a role in interspecific interactions between the two species.【Methods】 The optimal blends of the two major components for trapping F. occidentalis and F. intonsa female adults in fields were determined by field trapping experiments. In addition, cage experiments were conducted to determine the role of aggregation pheromones in the interspecific interaction between the two closely related thrips species. 【Results】 The results showed that the optimal blend for trapping F. occidentalis adults was 1 250 ng (R)-lavandulyl acetate and 10 000 ng neryl (S)-2-methylbutanoate, while that for trapping F. intonsa adults was 1 250 ng (R)-lavandulyl acetate and 5 000 ng neryl (S)-2-methylbutanoate. In addition, the synthetic aggregation pheromone blend of F. occidentalis determined above had no significant trapping effects on F. intonsa adults and vice versa, suggesting that the aggregation pheromones of the two closely related species are species specific. 【Conclusion】 This study confirmed that species-specificity in aggregation pheromones in the two closely related thrips species is regulated by the ratio of the two major compounds. Meanwhile, the species-specificity might contribute to the pre-mating isolation and reduction of competition between F. occidentalis and F. intonsa. These results provide a theoretical guidance for further understanding the physiological and molecular mechanisms of chemical divergence in the two thrips species, and also a guide for population monitoring and pest control of thrips using aggregation pheromones.

 【Aim】 This study was conducted to monitor the population changes of most dominant species of the peach fruit fly, Bactrocera zonata distributed at seven localities (Sargodha-Ⅰ, Sargodha-Ⅱ, Bhagtanwala, Sakessar, Chak# 75-SB, Chak# 46-SB and Chak# 104-NB) of Tehsil Sargodha from 2009 to 2011. 【Methods】 Population occurrence of B. zonata was recorded on weekly basis using methyl eugenol pheromone traps charged at fortnight intervals. 【Results】 The results revealed that the highest population abundance of B. zonata was recorded at Sargodha-Ⅰ (53.67, 45.82 and 45.47 flies/trap) followed by Sakessar (41.13, 33.87 and 35.75 flies/trap) whereas Chak# 75-SB had the lowest population occurrence (15.78, 19.18 and 19.15 flies/trap) during all the three years (2009-2011), respectively. The highest peaks were observed during April (76.08, 71.94 and 61.51 flies/trap, respectively) followed by May (60.74, 52.63 and 64.00 flies/trap, respectively) and the lowest during February and October each year. Moreover, there were strong positive relationships between the maximum and minimum temperature and B. zonata population abundance where negative association was observed for the relative humidity and rainfall. Similarly regression coefficient demonstrated that the maximum temperature was the major contributing factor influencing B. zonata population occurrence and rainfall contributed the lowest share. 【Conclusion】 Regular inspection of B. zonata population should be carried out throughout the year, especially when temperature started to rise in April-May as weather factors greatly influence population counts of B. zonata.

Abstract: 【Aim】This study aims to provide the basic scientific data of aquatic insect species in Inner Mongolia and a solid base for their potential application in freshwater quality monitoring and protection by the government and scientists in the future. 【Methods】Benthic aquatic insects were sampled by using a qualitative collection method and the water quality was assessed by the family biotic index (FBI), EPT species richness and Shannon-Wiener biodiversity index.【Results】Of 187 freshwater insect species in 72 genera, 59 families, 7 orders collected in the 52 localities, 1 species was new to science; 2 families, 3 genera and 25 species were newly recorded in Inner Mongolia; 1 genus and 2 species were recorded for the first time in China; and 56 additional species are under identification. The diversity of Trichoptera and Ephemeroptera were the highest while that of Plecoptera was the lowest in recorded 7 orders; the proportions of families and individuals of the two orders accounted for 42.37% and 84.29%, respectively, so Trichoptera and Ephemeroptera are dominant groups among the seven orders. The localities of rich species diversity were distributed mainly in the eastern Inner Mongolia, including Hulunber, Hinggan League, Tongliao and Chifeng. The water quality ranks assessed by the family biotic index, EPT species richness and Shannon-Wiener biodiversity index showed that the evaluation results of FBI and EPT species richness were similar, but differed greatly from that of Shannon-Wiener biodiversity index. 【Conclusion】 There are more abundant species of Trichoptera and Ephemeroptera with lower tolerance value in Inner Mongolia, so the caddisflies and mayflies are more suitable and better candidates as indicators of water quality in this region.