Aldehyde oxidases (AO, EC 1.2.3.1) are a group of protease belonging to the large family of molybdo-flavoenyzme (MFE). In order to research the function of these proteases, aldehyde oxidase genes of the silkworm, Bombyx mori (BmAOXs) were identified and analyzed in this study. Eight candidate genes of BmAOXs sharing the conservative domain with aldehyde oxidases from other species were identified based on the silkworm genomic database. Phylogenetic analysis indicated that BmAOXs were clustered into a cluster with AO proteins of other insects. The results of RT-PCR analysis showed that BmAOX1, BmAOX2, BmAOX3 and BmAOX5 were highly tissue-specific; BmAOX4, BmAOX6, BmAOX7 and BmAOX8, however, showed a broad expression profile in different tissues of both pupa and adult, suggesting that they may play important roles in the silkworm metabolism. By Native-PAGE and active staining, five and six active aldehyde oxidases were detected in tissues of pupa and adult of the silkworm, respectively, but they were in different types and activity levels. These results could provide insights into the further functional research on BmAOX gene family.

Neuropeptides play an important role of regulation for the silkworm, Bombyx mori. To fully comprehend the regulation of neuropeptides in the growth of B. mori and to get more neuropeptides in B. mori, the online program tblastn of BLAST and the search program of OpenOffice software were used to screen genes encoding putative neuropeptide precursors in the databases of silkworm genome and theoretical proteins based on the homology and the structure of the neuropeptides conserved in other insects and invertebrates. Several online programs were used to analyze the structures of the genes and the theoretical proteins to predict the mature peptides. As results, 31 neuropeptide gene families with 37 gene subfamilies including allatostatin-A (AST-A), allatostatin-B (AST-B), allatostatin-C (AST-C), allatropin (AT), bombyxin, ecdysis-triggering hormone (ETH), crustacean cardioactive peptide (CCAP), and FMRFamide were identified. A total of 44 neuropeptide genes and 193 mature peptides were predicted. Among them, 73 neuropeptides are amidated at the C-terminal, six neuropeptides are cyclized at the N- terminal, and nine neuropeptides are sulfated. Most of the mature peptides share the similarity because they belong to the same family. But compared with that of other insects, mature peptides of proctolin, CCAP and CAPA-PK are more advanced in the structure. The results suggest that the neuropeptide precursors, which are possessed by almost all the insects, are produced by nerve and endocrine cells of B. mori, and in the course of evolution, differences in the amino acid sequences for most mature peptides formed among different insect species, but the motifs for the same family are highly conserved. This study provided useful information for future research on functions of neuropeptides, which will give us novel insights into the regulation of developmental process, especially at the pupal stage, in the silkworm.

To clarify the effect of heat shock protein 90 (HSP90) on tolerance to high temperature in larvae of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), a full-length cDNA encoding HSP90 from S. exigua was cloned and characterized by RT-PCR and RACE technique. The complete cDNA (2 453 bp) contains a 2 154 bp open reading frame encoding 717 amino acid residues   (GenBank accession no. FJ862050). The complete amino acid sequence of HSP90 deduced from the cDNA consists of 25 residues for the putative signal peptide and 692 residues for the mature protein with the predicted molecular weight of 82.6 kD and the isoelectric point of 5.0, respectively, and carries an important and intact HSP90 signature sequence. The nucleotide sequence of the cDNA is highly similar with the HSP90 cDNA sequences of some other insect species. In order to explore the effects of HSP90 on tolerance to high temperature, a standard system was designed for real-time fluorescence quantitative RT-PCR, with which the relative expression of HSP90 gene at different instars of larvae in response to high temperatures was detected. The results indicated that high temperature induced the HSP90 expression obviously. Relative expression levels of HSP90 gene increased with the increase of temperature. The HSP90 expression levels in larvae of all tested instars under 43℃ and 45℃ were significantly higher than that under the normal temperature. However, the HSP90 expression levels in larvae of different instars were not significantly different. The results suggest that HSP90 may play an important role in high temperature tolerance in S. exigua.

In order to clarify the molecular mechanisms of deltamethrin resistance in Spodoptera litura (Fab.), the esterase gene of S. litura was cloned by using the RT-PCR with degenerate primers and rapid amplification of cDNA ends (RACE) strategies, and designated as Slest2. Sequence analysis demonstrated that the fragment was 1 796 bp in full-length with a 63 bp 5′ UTR and 119 bp 3′UTR (GenBank accession no. DQ445461), the open reading frame encoded a 537-amino-acid protein. Homology analysis indicated that the deduced amino acid residues of Slest2 had very high similarity with those from other species, and contained several conserved domains in all esterase proteins. The relative expression level of Slest2 was compared between the resistant strain and the susceptible strain using real-time quantitative PCR technique. The transcription level of Slest2 tested with cDNA as template in the resistant strain was 46.85-fold as high as that in the susceptible strain. However, the test with gDNA as template indicated that the resistant strain and the susceptible strain had similar gene copies of Slest2 (the former was 1.16-fold as high as the latter). The results suggest that the higher transcription level of Slest2 contributes to insecticide resistance in S. litura.

The mechanisms and evolutionary dynamics of intron insertion and loss in eukaryotic genes remain poorly known. A total of 604 protein-coding genes, which contain 12 585 introns and 3 074 conserved introns in distinct amino acid alignment sequences in orthologous genes from Vertebrata (Mus musculus, Rattus norvegicus and Homo sapiens), Diptera (Anopheles gambiae) and plant (Arabidopsis thaliana) were analyzed using systematic methods to assess the causes of present-day distribution of introns in different lineages. The results demonstrated that more than 850 introns lost in Diptera evolution and more than 1 600 introns gained in Vertebrata evolution, but the intron gain in Diptera evolution and intron loss in Vertebrata evolution are relatively less. Additionally, along with yeast, the distribution of introns in Diptera exhibits a bit more prevalent in the 5′end of genes, which was not found in vertebrates and plants. This may be due to intron loss mostly occurring in 3′end of genes in Diptera evolution. Meanwhile statistical results indicate that phase 0 intron is most common in the three species in Vertebrata, and this might be the consequence of that phase 0 intron was the most frequently gained intron type in evolution.

To better employ the alternative method for monitoring and controlling the green leaf bug, Lygus lucorum, with sex pheromone analogs and plant volatiles, electroantennogram (EAG) responses of adult L. lucorum to nine analogs of sex pheromone and twelve volatiles of plant were tested. The results indicated that EAG responses of L. lucorum to butyrates and green leaf volatiles (GLVs) were stronger than that to other compounds examined. Males were more sensitive to analogs of sex pheromone than females, while females more sensitive to plant volatiles. Among nine analogs of sex pheromone tested, (E)-2-hexenyl butyrate elicited the strongest EAG response. Among the plant volatiles tested, (E)-2-hexenal was the most stimulating. The females were more sensitive to such GLVs as (E)-2-hexenol, (E)-2-hexenal and (Z)-3-hexenol than to terpenoids. Dose response curves of EAG of L. lucorum showed that compared with females, males showed significantly stronger EAG responses to (E)-2-hexenyl butyrate at all tested concentrations, while significantly weaker EAG responses to β-pinene. Sensitivity differences between both sexes to sex pheromone analogs and plant volatiles suggest ecological adaptation of this species: the males are more sensitive to sex pheromone analogs, which will be helpful for their orientation towards females; whereas the females are more sensitive to plant volatiles, which will be useful for their finding of hosts.

To study the effects of brood pheromone esters (three aliphatic esters, i.e., methyl palmitate, ethyl palmitate and ethyl oleate ) on development and foraging behavior of Apis cerana cerana workers), 1 day-old workers were fed with different food, of which the treatment group workers were fed with food (candy) mixed with one of the aliphatic esters at 1% or 0.1% (w/w), the control group workers were fed with food (candy) without any aliphatic ester; then, the percentage of workers with developed ovary at two phases (7 and 14 day-old), the width of hypopharnyngeal glands of workers at six phases (3, 5, 7, 12, 18 and 21 day-old) and the first foraging age were tested. The results showed that (1) At 7 and 14 day-old, the workers fed with methyl palmitate (1%, 0.1%) with developed ovaries were less than the control group in queenless colony. At 14 day-old, the workers with developed ovaries treated with ethyl palmitate (0.1%) were significantly less than the control group in queenless colony. At 14 day-old, the workers fed with methyl palmitate (1%) and ethyl oleate (1%, 0.1%) were both significantly less than the control group in queen-right colony. (2) At 5 and 7 day-old, the widths of hypopharnyngeal glands of workers tested with methyl palmitate (1%, 0.1%) in queen-right colony were longer than the control group, while shorter than the control group at the later phases (12, 18 and 21 day-old). From 7 to 21 day-old, the hypopharnyngeal gland development of treated workers with ethyl oleate (1%, 0.1%) was shorter than that of the control group. (3) Of the three aliphatic esters, only methyl palmitate exerted a stronger effect, causing a significant delay to first foraging age. The results suggest that different brood pheromones of honeybee have different biological effects on development and foraging behavior of Apis cerana cerana workers.

In order to find a faster and more effective method to use entomogenous fungus Isaria javanicus to control the diamondback moth, Plutella xylostella (L.), bioassays were carried out to clarify if destruxins can influence mycelia growth production and germination of conidia spores of the strain SP053, and to evaluate their joint toxicity against the 2nd instar larvae of P. xylostella. The results indicated that destruxins had no significant effect (P>0.05) on strain growth and conidia production and germination. However, there was certain synergism between destruxins and conidia spores of the  strain SP053. The mixtures of S50-CD100 (meaning the mixture of conidia spores of the concentration 50×10⁵/mL and crude destruxin of the concentration 100 mg/L; other mixtures indicated in the same way), S25-CD100, S25-CD50 and S12.5-CD100 showed distinct synergism. The S25-CD100 combination showed the highest effectiveness with the cooperative virulence index (c.f.) reaching 52.31 and 31.07 at 48 and 72 h after treatment, respectively. This synergism was verified by virulence bioassay as well. The mixtures contained crude destruxin (CD) from 25 to 100 mg/L had lower LC₅₀ values, for example, the LC₅₀ values of the mixture SP053-CD100 (containing CD 100 mg/L) at 48 and 72 h were 17.45×10⁵ and 10.55 ×10⁵ spores/mL, respectively; meanwhile, those of the control (without destruxins) were >50×10⁵ and 35.85 ×10⁵ spores/mL, respectively. It is so concluded that the mixing of destruxins and the I. javanicus strain SP053 has synergism against P. xylostella. This result may be used to improve biocontrol of the pest.

In order to explore the thermal adaptability to elevation in the pine armored scale (PAS), Hemiberlesia pitysophila Takagi, an invasive forest pest originated in Japan which had been severely attacking various ever green pines in southern China in the recent two decades, the cold and heat tolerances of 1st instar nymphs, 2nd instar nymphs before sexual differentiation and adult females of the winter field populations of PAS collected from five plots at different elevation (80, 251, 391, 510 and 725 m, respectively) were compared, based on the survival experiments exposed to extreme temperature conditions in Quanzhou, Fujian in February, 2009 and the measures of supercooling point (SCP). The results showed that (1) thermal tolerances of PAS at different elevation had significant differences, in which adult females and 2nd instar nymphs all displayed higher cold tolerance at the elevation of 391 m, and an increased heat tolerance in adult females at the same elevation was observed too. Cold tolerance seemed to increase with increasing of elevation in the 2nd instar nymphs, but not in other developmental phases. This finding though provides an opponent case of climate variation hypothesis, it suggests that elevation might be an important limit to population expansion and geographic distribution of PAS. (2) Pearson’s correlation between cold and heat tolerance in adult females was statistically remarkable and positive along an altitudinal gradient, but no correlations existed in other developmental phases, suggesting that the developmental phase of PAS might affect this correlation. (3) A separate analysis showed no marked Pearson’s correlation between SCP and median lethal low temperature of adult females in PAS exposed for 4 h along elevation gradient. These results provide a helpful foundation to profoundly understand thermal adaptability and geographic distribution in PAS.

Tetrastichus hagenowii （Ratzeburg） adults are minute endoparasitoids that attack only insect eggs, mainly those of Blattaria. Laboratory studies were conducted to determine the reproductive biology of the parasitoid for its potential as a biological control agent of cockroaches. The results showed that T. hagenowii employed parthenogenesis and sexual reproduction. The sexual reproduction produced 46.02% female progeny, but the parthenogenesis produced only male progeny. The female T. hagenowii has a pair of ovaries, each consisting of 8 to 12 of ovarioles. One ovariole has 1 to 6 eggs. The number of eggs in the ovaries for 1-d-old female was 45.2, while for 2-d-old female 80.1. The oviposition period ranged from 4 to 11 d. The average fecundity per female per day was 0.86-7.57 within 11 d after emergence. A female wasp parasitized one ootheca on average during her lifetime. The parasitism was affected by the ratio of wasps to host oothecae. The parasitism increased with increasing of the ratio of wasps to host oothecae within 1∶5-3∶1, but the number of parasitized oothecae per female declined.

【Aim】Bemisia tabaci is a species complex with rapid evolutionary modifications. In recent years, its biotypes gained more attention because of its increasing hazards to the agricultural crops. Previously there were few sympatric non-B biotypes in different regions of China except B biotype. The study described herein provides some theoretical basis for its biotype detection and integrated control by identifying its biotypes which currently prevail in China and their relationship with different biotypes from other countries.【Methods】The biotypes and phylogenetic relationships of 22 different non-B biotype populations collected from six provinces were studied based on 16S rDNA sequences. 【Results】 The results revealed that the 22 different populations of non-B B. tabaci belong to Q, Nauru and An biotypes. Evolutionary divergence among these biotypes was more than 10%. The relationship between Q and B biotypes was closest, with genetic distances between 2.8% and 4.0%. The genetic distances among different biotypes were significantly higher than within the same biotype, while Q biotype showed the least genetic distance of 0.9% within itself. It is a universal phenomenon that multiple biotypes prevail in the same region. The Nauru biotype was more widely distributed than the other two biotypes. The highest variety of non-B biotypes was detected in Yunnan province. 【Conclusion】 The genetic differentiation of B. tabaci is very complicated. The biotypes of B. tabaci can be effectively identified using 16S rDNA gene.

This study aims to provide general technicians who manage pests in production with a convenient way to recognize insects. A novel method to classify insects by analyzing color histogram and dual tree complex wavelet transform (DTCWT) of wing images was developed. The wing image of lepidopteran insect is preprocessed to get the region of interest (ROI). First, the color image is converted from red-green-blue (RGB) to hue-saturation-value (HSV) space, and the 1D color histogram of ROI is generated from hue and saturation distribution, respectively. Then, the color image is converted to grayscale image, and rotated and translated to a standard position to extract the DTCWT features. Matching is first undergone by computing the correlation of the histogram vector between testing and template images. If the correlation is higher than a threshold, then their DTCWT features are further matched. The DTCWT feature matching are realized by computing their Canberra distance, and the nearest neighbour is considered as the most matched species. The method was tested at the insect database with images of 100 lepidopteran species, the recognition rate was as high as 76%, and the recognition rate for the subset of forewing images was as high as 92%. An ideal time performance was also achieved. The test results proved the efficiency of the proposed method.

To improve crop production and protection, and to implement timely targeted pesticide applications, reducing input costs and benefiting the environment, an accurate early detection and quantification of damage caused by crop insect pests in plants is required. Traditional methods such as plant-flapping method which investigates the population of insect pests by macroscopic observation with the tracking down rate between 30% and 70% are most common but subject to bias and can be inaccurate. These imprecise and inaccurate detection and damage evaluation data, however, may cause costly errors to variable-rate spraying in precision agriculture. This paper provides an overview of the recent literatures on machine-based technologies for detecting and monitoring field crop insect pests. Techniques which have been used in detecting and monitoring insect pests include methods of acoustic detection, radar observation and spectral scanning. Some of the main constraints of these progress and solutions where rapid advances seem possible in the machine-based technologies for detecting insect pests of crops are discussed. As for the difficulties in the machine-based technologies for detecting crop insect-pests, such as field conditions complicated variables, injured position uncertainty, and many interference factors, possible approaches are outlined, including that future research should focus on combined detection methods under field conditions.

Locke recently proposed that insects have lungs, which raised a new concept and a new area of interest in insect physiology and morphology. The existence of lungs of 62 insect species, belonging to 37 families in eight common orders, was detected by means of anatomy and histology methods. The results showed that the pupae and adults of Leucania separata and Sylepta derogata have no distinct lungs. However, lungs exist in almost all larvae of Lepidoptera. The lungs become more distinct or clear in more advanced groups of Lepidoptera than in less advanced ones. Although the larvae or nymphs of the examined species of Orthoptera, Mantodea, Homoptera, Hemiptera, Coleoptera, Diptera, and Apidae (Hymenoptera) have no distinct lungs, their tracheae become more complex in more advanced groups than in less advanced ones. The tracheae of the larvae of Argidae (Hymenoptera) function as lungs. Our study concluded that lungs in the eight insect orders examined show a trend from nonexistence to existence and from simple to complex.

The infection process of Beauveria bassiana conidia on cuticle of Solenopsis invicta was observed using scanning electron microscope (SEM). The results showed that most of conidia were deposited on intersegmental membranes, folded regions on thorax, spiracles, cavities, setae and coxae of legs. The germinated conidia mainly invaded the worker cuticle from intersegmental membranes, as well as setae, cuticle cavities, rugous regions on cuticle and tibiae. The conidia adhered on worker surface began to germinate at 12 h after inoculation. The first penetration of germinated conidia occurred in intersegmental membrane at 18 h after inoculation, followed by penetration of conidia around setae at 24 h after inoculation. Conidia on all kinds of surface topography including the thorax, abdomen and legs successfully invaded into the cuticle and resulted in infection at 60 h after inoculation. The germinated conidia of the isolate either invaded the cuticle directly with germ tube or invaded the cuticle by producing appressorium during the course of infection.