Olfaction plays an important role in insect behaviors for survival and reproduction. In this study, we obtained two cDNA fragments encoding two silkworm pheromone binding proteins, named BmPBP2 and BmPBP3, respectively. Together with already reported silkworm PBP1 and two general odorant_binding proteins (GOBPs), all these five genes, consisting of three exons, have conserved exon/intron boundary and six characteristic cysteines. Of them, the three PBP genes are present in tandem arrays. Homology analysis showed that the BmPBP2 and BmPBP3 had about 69% and 63% identity with PBPs from Manduca sexta, respectively. Semi-quantitative RT-PCR analysis indicated that BmPBP2 and BmPBP3 were specific expressed in female and male antennae with the same level. These results show that BmPBP2 and BmPBP3 are possibly involved in pheromone detection and discrimination.

The cDNA of Helicoverpa armigera prophenoloxidase (PPO) was cloned by means of RT-PCR and RACE. The cDNA was 2 405 bp in length and contained an open reading frame (ORF) of 2 097 bp which encoded 698 amino acid residues. The deduced amino acid sequence showed a high identity to the reported sequence of PPO2 from other insects and shared the typical structural features of PPO from other insects. The results of RT-PCR showed that PPO mRNA was expressed in integument，haemocyte and midgut of H. armigera.

 

The cDNA encoding phospholipase A₂ of Apis mellifera (AmPLA₂) was cloned into a transfer vector pFastBacHTa to form the recombinant donor plasmid pBacHT-AmPLA₂. The recombinant donor plasmid was then transformed into Escherichia coli DH10Bac. By transposition, AmPLA₂ gene was integrated into Bacmid, and a recombinant shuttle vector, rBacmid-AmPLA₂ was constructed. The cultured Trichoplusia ni Tn-5B1-4 cells, mediated with Lipofectin, were transfected with the rBacmid-AmPLA₂ DNA, and then the recombinant baculovirus, rACV-Bac-AmPLA₂ was obtained. The recombinant virus was further used to infect the Tn-5B1-4 cells to express the target protein. SDS-PAGE analysis of the infected cellular proteins showed that the size of the expression product of AmPLA₂ fused with 6×His tag at its N-terminal was about 18 kD, and the expressed protein accumulated up to about 5.35% of the total cellular proteins. Western blot analysis using anti-AmPLA₂ polyclonal serum confirmed the expressed protein was a fusion protein of AmPLA₂. The protein extracts of AmPLA₂ showed an enzymatic activity of about 6.13 μmol·min^-1·mg^-1 for hydrolyzing egg yolk substrate.

 The mechanisms and evolutionary dynamics of intron insert and loss in eukaryotic genes remain poorly understood. Here systematic methods were used to assess the causes of the present-day distribution of introns in different lineage in 105 protein-coding genes containing 3 574 introns and 1 001 intron conserved sites in distinct amino acid alignment sequences in orthologous genes from 6 genomes of vertebrates (Mus musculus，Rattus norvegicus and Homo sapiens), Diptera (Drosophila melanogaster and Anopheles gambiae) and nematode（Caenorhabditis elegans）. It was inferred that the common ancestor of vertebrates, Diptera and nematodes hold numerous introns, which were lost in Diptera or nematodes. The loss was even more serious in Diptera than in nematodes. Furthermore, there were a fewer intron gain than loss in nematodes, but there were even more intron loss than gain in Diptera. The results felicitously explain that the number of introns distributed in vertebrates, Diptera and nematodes are declining sequentially.

Effect of transgenic poplars on the activities of three protective enzymes (SOD, CAT and POD) in the midgut and haemolymph of Micromelalopha troglodyta (Graeser) larvae fed with leaves of transgenic poplars expressing Bt gene only (FB56) and expressing Bt and CpTI genes (D18) was studied in the laboratory using enzyme activities determination. The results showed that the SOD activity in the midgut of the larvae was raised significantly, while the CAT and POD activities were controlled significantly. When the larvae were fed with the leaves of FB56 for 24 hours, the activity of SOD in the midgut of the larvae was raised by 41.7%, which had significant differences with CK. But SOD activity was raised by 25.3% after treating with D18, which had no significant difference with CK. After 24 hours feeding on FB56, the activity of CAT in the midgut of the larvae was restrained significantly, but the restraining ability was not strong after 36 hours. But CAT activity was controlled significantly after treating with D18. FB56 and D18 all restrained the activity of POD in the midgut of the larvae greatly after 36 hours treatment, and the activity decreased by 70.1% and 89.8% respectively. Thus, the transgenic poplars could delay the cleaning of free radicals in the body of M. troglodyta, and disturb the dynamic balance of SOD, CAT and POD in the midgut of the larvae, which was the one of acting mechanisms. The harm of the transgenic poplars expressing both Bt and CpTI to the larvae is stronger than transgenic poplars expressing Bt alone. The activities of SOD and POD in the haemolymph of the larvae had no significant difference with CK after treating with leaves of two kinds of transgenic poplars, but the activity of CAT had a significant increase compared with CK. Thus, the influence of transgenic poplars on the endogenous protective enzymes in the haemolymph was smaller than that in the midgut.

By feeding the host, Spodoptera litura Fabricius, larvae with artificial diets treated with different concentrations of zinc for 4 generations, the side effects of zinc on the survival and development of Microplitis bicoloratus Chen, a larval parasitoid of S. litura, were estimated. The results indicated that the zinc contents of S. litura hemolymph increased with the increase of zinc concentrations in diets and generations of the phytophagous insect. The parasitism rate, time from parasitism to pupae, pupal duration, adult emergence rate, and adult female longevity of M. bicoloratus wasp were influenced to some extent. Specially, the adult emergence rate of the first generation and the parasitism rate of the second generation decreased significantly with the increase of the zinc concentration in their host diets. It was so concluded that high dose zinc in the diet of herbivorous insects affected the survival and development of their larval parasitoid M. bicoloratus through food chain to some extent.

The obligate aphid pathogen, Zoophthora anhuiensis (Li) Humber (Entomophthorales), is difficult to be propagated in vitro. In this study, the broomcorn millet Panicum miliaceum L. in flasks was used as solid substrate to ease in vitro propagation of the fungal pathogen. Properly steamed millet grains in flasks were mixed with pieces of the fungal colonies grown on the plates of Sabouraud egg yolk-milk agar and then maintained for stationary incubation at the regime of 20℃ and 12L∶12D. The 7-day-old millet cultures produced 13.0×10⁴ conidia/grain and persistently sporulated for up to 6 days. The conidia discharged from the cultured grains were used to inoculate via spore shower the nymphs of the green peach aphid Myzus persicae (Sulzer) on cabbage leaves at nine dosages of 7.9～134.9 conidia/mm². Data resulted from 7-day observation of the inoculated aphids fit very well to the time-dose-mortality model. Based on time- and dose-effect parameters estimated from the modeling, the LC₅₀ and LC₉₀ of the fungus against M. persicae were 59.8 and 354 conidia/mm² on day 5 after spore shower, 39.5 and 234 conidia/mm² on day 6, and 33.5 and 198 conidia/mm² on day 7, respectively. The LT₅₀ decreased to 4.3 days at the dose of 134.9 conidia/mm² from 5.1 days at 57.7 conidia/mm². The results showed that the millet method for propagation of the obligate aphid pathogen was not only easy and convenient but produced desirable millet cultures with each grain sporulating very well and infecting aphids as a natural host cadaver.

Monochamus alternatus Hope is a main insect vector of pinewood nematodes (Bursaphelenchus xylophilus Nickle), which causes the serious pine wilt disease. Organophosphate is a kind of common insecticide used for the control of the pest insect. In birds and mammals, some organophosphates can cause a syndrome called organophosphate-induced delayed neurotoxicity by inhibiting neurotoxic esterase (NTE). The activity of the enzyme was found in various organisms, but people know little about it in insects and especially its physiological functions at the present time. We detected the NTE activity in larva of M. alternatus by using the differential assay method, and found that the enzyme activity in the head was 2.80±0.30 nmol·min^-1·mg^-1, which was nearly 10 times that in the fat body of the insect, but much lower than that in birds and mammals. The NTE activity from the insect head could be inhibited by methamidophos in vivo; however, in vitro, the NTE activity was found to be insensitive to methamidophos, which was quite different from that in birds and mammals.

We assessed the effects of the extracts from Sabina vulgaris Ant., and two podophyllotoxin analogues, i.e., podophyllotoxin and deoxypodophyllotoxin, which are main insecticidal secondary components of S. vulgaris, on growth and food utilization of Mythimna separata larvae with weight method under treatment with three doses of AFC₃₀, AFC₅₀ and AFC₈₀. The results showed that the tested chemicals had obvious inhibiting activity on growth and development of M. separata larvae, and the larval stage was significantly longer when controlled with the three chemicals under above doses. During treated periods, the related growth rate (RGR) and related metabolizing rate (RMR) were significantly lower when controlled with the two podophyllotoxin analogues, and the higher the dose, the lower the rates. But in 3－5 days post treatment, these two rates recovered to common levels. The three chemicals had no obvious effects on larval approximate digestibility (AD). During the controlled period, the efficiency of conversion of digested food (ECD) and efficiency of conversion of ingested food (ECI) significantly increased. In 3－5 days post treatment, these two rates also recovered to common levels. There was a certain extent difference of ECI and ECD among controlled chemicals, but no obvious difference among doses.

The spatial distribution of the Oriental migratory locust, Locusta migratoria manilensis (Meyen) egg pods was studied by integrating geostatistical analysis and GIS techniques. Data of egg pods were collected from both spatial scales over two years of extensive surveys: 450 m intervals for the whole study area, then 50 m grid for possible egg-laying areas which were located on the areas damaged by the locust plague or covered with sparse vegetation. Meanwhile, site ecological variables including vegetation coverage, and soil parameters (salinity, pH, water content at 5 cm depth, organic matter, etc.) were surveyed at these grid points. The results showed that three site variables including vegetation coverage, soil water content at 5 cm depth and soil salinity were significantly different between sites with and without egg pods, and the preferable ranges for L. m. maniliensis oviposition were 0-30%, 10.1％-20.0% and 0.09％-1.99% for these three variables, respectively. No eggs were laid when vegetation coverage exceeded 50%, soil water content at 5 cm depth was higher than 30%, or soil salinity was above 3%. Semivariograms indicated that the distribution of egg pods was in high heterogeneity. Spatial autocorrelation in egg pod distribution was at distances about 390 m. The spatial distribution of egg pods was patchy and aggregated in the two years and could be best described using spherical models. GIS risk assessment maps, derived by block kriging, displayed the probabilities of occurrence of the locust egg pods at an area-wide scale. The results may provide useful information on planning for sampling in the field, tracking embryo developments, monitoring targets and taking site-specific measures towards this locust.

 

The occurrence and spatial distribution of Erythroneura apicalis (Nawa) populations infesting grapes in Turpan area, Xinjiang were investigated and analyzed by using Taylor's Power Law and Iwao's regression method. The results showed that the E. apicalis could complete 4 generations every year in Turfan aera. The first peak appeared during the second ten days of May and the rest generations overlapped with each other. The spatial distribution of its populations linked with the variation of temperature. During the spring with temperature variation between 20℃ and 30℃, its populations tended to colonize the middle and upper part of pergola of grape. With the temperature rising during summer, the population transferred to the middle and lower position of pergola, and got through the extreme temperature with such habits as hiding below the veil and staying at the cool and humid surface of soil, etc. The analysis of Iwao's patchiness and Taylor's law showed that the spatial pattern of E. apicalis within its developmental period was aggregated. It was also confirmed that E. apicalis had the characteristics of regular aggregation and dispersion incidence in its population dynamics.

Tomato has been listed as a host plant of the oriental tobacco budworm (OTB), Helicoverpa assulta for long time in literatures in our country, with which many reports from the field surveys disagreed. The present investigation aims to clarify if tomato plant is OTB host. Laboratory trials showed that OTB moth laid eggs on tomato plant, but neither detached tomato leaves nor potted plant supported neonate growth, and all the 3rd instar larvae feeding on the green fruits died before the 6th instar too. Death of the larvae could be attributed to presence of tomatine in these organs, and its contents reported in the literatures are in close to or exceed the LC₅₀ of 744 ppm for the neonates  as estimated using the artificial diet with different contents of the chemical. The field survey also excluded possibility of OTB infesting tomato plants. These results suggest that tomato plant is not OTB host and the records in the literatures might confuse H. armigera and H. assulta because of their similarity in morphology and feeding habits.

To explore the effect of between breeding temperature on the endosymbiotic bacteria in Aphis fabae Scopoli and body size of their hosts, the changes in the abundance of mycetocytes and host body size under different temperatures were observed in the laboratory. The results showed that the effect of temperature on the abundance of mycetocytes was dependent on the developmental stage of aphids. The abundance of mycetocytes in the 1st instar nymphs of the aphid showed no difference at different temperatures except at 25℃ and 35℃, but showed significant difference in the other life stages of the aphid at different temperatures, and a negative correlation between the abundance of mycetocytes and temperature was found. Temperature also affected, to some extent, the trend of the abundance of mycetocytes following the development of aphids. The abundance of mycetocytes increased with the development from nymph to adult before larviposition in the aphid at 15℃，20℃ and 25℃, but culminated at the 3rd instar and thereafter declined at higher temperatures (30℃ and 35℃). Aphid body size in all stages except for the 1st instar declined with the increase of temperature but increased with the abundance of mycetocytes at all temperatures except at 35℃. It is tentatively hypothesized that temperature affects aphid body size via influence on the abundance of mycetocytes.

 Development and parasitization of Trichogramma dendrolimi infected by Wolbachia were observed at 16℃, 20℃, 24℃, 28℃ and 32℃ respectively. The results showed that the developmental duration of T. dendrolimi infected by Wolbachia was affected by temperature. The higher the temperature, the shorter the duration. The whole developmental duration was 23.2 d, 17.8 d, 13.2 d, 11.1 d, and 7.8 d at 16℃, 20℃, 24℃, 28℃ and 32℃, respectively. The thermal threshold, the effective accumulated temperature, the innate capacity of increase (r_m) and the net reproduction rate (R₀) of T. dendrolimi infected by Wolbachia were estimated as 7.40℃, 212.69 degree-day, 0.2448-0.4584 and 28.00-84.03, respectively. The results suggested that the optimal reproduction temperature of T. dendrolimi infected by Wolbachia was 24℃-28℃.

 Based on the information of daily climatic records of 634 stations in China and the biological characteristics and distributions of Frankliniella occidentalis (Pergande) in the world, the potential distribution areas of F. occidentalis in China were analyzed with the models of Match Climates and Compare Locations of the software CLIMEX. The results showed that F. occidentalis could prevail in Guangdong, Hainan, Anhui, Fujian, Jiangsu, Shandong, Guangxi, Guizhou, He'nan, Hubei, Shaanxi, Sichuan and Yunnan provinces and Chongqing city, but was unable to survive in Xinjiang, Qinghai, Tibet, Heilongjiang, Jilin, Liaoning, and Inner Mongolia provinces or autonomous regions in the northeast and northwest of China. The north limit of its distribution in China was located along the joining line of such cities as Weihai, Yantai, Ji'nan, Dezhou, Xingtai, Yuncheng, Xi'an, Baoji and Tianshui, where the annual average temperature is 10℃, the average temperature in January -8℃, and the annual extremely lowest temperature -20℃.

The influence of different host fruits on the cold hardiness of oriental frit fly Bactrocera dorsalis (Hendel) was evaluated in the laboratory. One day old pupae bred with 15 different melons and fruits were chosen to test for their supercooling points (SCP). Furthermore, the SCPs of 3rd instar larvae, one day old pupae, 3 days old pupae, 5 days old pupae, 7 days old pupae and 2-3 days old adults (male and female) bred with five host plants (pumpkin, tomato, citrus, guava and star fruit) were measured, and the survival of one day old pupae bred with these five plants at low temperatures was observed. The results showed that the mean SCPs of one day old pupae of B. dorsalis bred with 15 different host fruits ranged from -11.03℃ to -13.17℃. Moreover, these values were significantly different at 0.05 level, and these fed on rose apple had the highest SCP （-11.03℃）, while those fed on balsam pear had the lowest SCP （-13.17℃）. The mean SCPs of B. dorsalis at the same developmental stages bred with the five host fruits further tested were significantly different from each other (F_(4，863)＝35.6，P<0.01). The mean SCPs at different developmental stages of B. dorsalis bred with the same host were also markedly different from each other (F_(6，863)＝392.9，P<0.01), and there were notable interaction between host fruits and the fruit fly developmental stages (F_(24，863)＝9.4，P<0.01). There were some changes among the mean SCPs of different developmental stages of B. dorsalis. From the 3rd instar larvae to one day old pupae, the SCP values were low and there were no significant difference between them. But for the pupae of 3 days old, 5 days old and 7 days old, their SCP values decreased notably, with the lowest point -20℃; however, there were no significant difference among them. For the 2-3 days old adults (female and male), the mean SCPs increased again to -10℃. The SCP values for the 3rd instar larvae, one day old pupae and adults were significantly higher than that of pupae at other three developmental stages. In order to determine the survival response to various cold stress in different host fruits of B. dorsalis, acute low temperature (-3℃) (1-8 h) and chronic low temperature (6℃) (1-8 days) regimes were designed, the corrected survival rate of the one day old pupae fed on guava, star fruit and pumpkin were higher significantly than that of the pupae fed on tomato and citrus. By exposing them to the selected low temperatures (0℃, 3℃, 6℃ and 9℃) for 2 days, the same results were obtained. Therefore, it could be concluded that different host fruits could influence the cold hardiness of next generation of B. dorsalis, and the reason underlying this needs to be further explored.

 The parasitizing behavior of the bathyluid Scleroderma guani on the pupa of the yellow mealworm, Tenebrio molitor Linnaeus was investigated in the laboratory. The parasitism process was divided into six stages，i. e. assembling, recognition, stinging, clearing and feeding, oviposition and protecting protelean bathylid. The recognition and stinging of the female bathylid to the pupa have much difference between female individuals. The time before stinging the host is 1.4－7.0 d , and the rate of the stinging is 8.7%-91.7%. The influence factors on the recognition and stinging rate included the female mating, host freshness and temperature. The stinging could keep the host alive and fresh, and made them suitable to be parasitized by the bathylid. On the average, the pupa of yellow mealworm was kept fresh for 12.6 days after being stinged. The average number of laying eggs for the S. guani is 30, and the biggest is 91. The eggs in the pupa body were evenly distributed, and this to facilitated the use of host nutrition by larvae of the bathylid. The female showed the behavior of protecting protelean bathylid, including protecting eggs and mustering old larvae. 6 Refs.

This paper studies the influences of forest regeneration on the species diversity of sarcosaprophagous beetles (Coleoptera) in Wolong Natural Reserve (102°52′-103°24′E, 30°45′-31°25′N), Southwestern China. Comparisons were made among larch plantations dominated by Larix kaempferi of different ages (namely, 5 years, 15 years, and 45 years after being planted) and natural deciduous broad-leaved forest (ca. 100 years old). Baittraps were used in the field collections and laid in two ways, on the ground and 1.5 m high above the ground. A total of 3 066 beetles were collected, of which 43.71% belonged to Staphylinidae, 31.83% Leiodidae, and 17.97% Silphidae. These three families are so considered as dominant groups. Species-abundance patterns fit the lognormal distribution; the patterns of the larch plantations, as their age increases, resembled more and more closely to that of the natural broad-leaved forest. Species richness and diversity were significantly lower in the larch plantations than in the natural broad-leaved forest, and the lowest values of both were observed in the 5-year-old larch plantation. Based on the species composition and abundance, sarcosaprophagous beetles of the three larch plantations and the adjacent natural broad-leaved forest could be separated from each other by ordinations based on principal coordinate analysis (PCoA) and cluster analysis. Our results showed that larch plantations could not completely replace natural broad-leaved forests in the role of conserving the biodiversity of sarcosaprophagous beetles.

The classificatory schema in some groups of Megachilidae reorganized by means of shape differences in terms of the inter- and intra-specific and inter- and intra-generic and subgeneric deformations. The relative warps, UPGMA trees and PCA graphs obtained from 30 landmarks were shown. Both Anthidium cingulatum Latreille and A. florentinum (Fabricius) should better classify in the same subgenus Anthidium s. str. In the other case under the results of shape variation our results supported the hypothesis that Paraanthidium as a subgenus of Anthidium Fabricius. On the other hand Icteranthidium Michener and Paraanthidiellum Michener showed enough dissimilarity to be kept as separate genera. Our analysis also supported the monophyletic origin of Megachilini which was clustered as a separate group by all methods used.  

Three genera with one species for each genus are reported as new records to the Geometrinae fauna of China: Absala dorcada Swinhoe, 1893, Calleremites subornata Warren, 1894 and Pachista superans (Butler, 1878). Descriptions for these genera and species are provided, and external features and genitalia of the three species are illustrated. Lectotypes of Absala dorcada Swinhoe and Pachista superans (Butler) are designated. The specimens studied are deposited in IZCAS (Institute of Zoology, Chinese Academy of Sciences), BMNH (The Natural History Museum, London), and ZFMK (Zoologisches Forschungsinstitut und Museum Alexander Koenig, Bonn) respectively.

 

Antifreeze proteins are also defined as thermal hysteresis proteins. They are one kind of functional proteins discovered in many organisms. When the temperature is subzero, they can bind to the surface of the ice nucleations to restrict their growth so as to protect organisms from injury caused by freezing. Insect antifreeze proteins have special structures such as repeat sequences, β-helix and TXT motifs. Additionally, they have stronger antifreeze activity than antifreeze proteins of other organisms. In this article, the special properties of insect antifreeze protein are introduced in detail; new advances on their structure and molecular biology are reviewed. Meanwhile, the function of TXT motif and the relationship between structure and function are discussed.

 

Recent advances in the studies of acetylcholinesterase (AChE, EC 3.1.1.7) genes from insects were reviewed. The gene structure, including ten extrons of insect AChE gene (ace), was discussed. All the ace genes reported from insects were summed up, and the phylogenetic tree was constructed based on the reported complete sequences of ace genes from insects. The ace structure characteristics, the functional sites of ace genes, the effect of ace mutation(s) on insecticide resistance and their relationships were also discussed. Finally, the problems and prospects in the studies of insect ace were analyzed.

 

Most hymenopterous parasitoids are able to discriminate previously parasitized and healthy hosts, avoiding super- and/or multiparasitism to minimize intra- and/or interspecific competition for food. Chemicals usually mediate the discrimination. These chemicals are defined as host-marking pheromones (HMPs). The HMPs are deposited by ovipositing females on the host surface, on the ‘containers’ in which the hosts are concealed, in the patch where hosts are harbored, or/and are injected into the host body before, during or after oviposition. Source structures of HMPs are associated with Defour’s glands, poison glands, oviducts, ovaries, eggs or corpora allata. HMPs are detected with antenna or ovipositors. Up to now, several HMPs have been chemically identified. Most of them are blends of saturated and unsaturated hydrocarbons. For Dendrocerus carpenteri, however, it is juvenile hormone. Several factors, such as HMP persistence, parasitoid intrinsic (egg load, age, experience or learning) and extrinsic factors (parasitoid density, available hosts, or host species), may affect the response of parasitoids to HMPs. The theoretical importance and potential applications of HMPs are also discussed.

 

This article reviews the acquisition, transmission and retention of geminiviruses by the whitefly, Bemisia tabaci. Minimum time required for acquisition and inoculation of geminiviruses by the whitefly is 15-30 min. Geminiviruses may be retained in their vector for one to several weeks, and sometimes for the entire life of the vector. Transmission efficiency increases with increase of acquisition time and inoculation time, or increase of the number of whiteflies used for inoculation and virus concentration. Moreover, the efficiency of transmission varies with age and gender of the insect vector. In addition to the direct transmission between plant and whitefly, geminiviruses can also be transmitted through mating and oviposition (transovarial transmission) among whiteflies. What geminiviruses that can be acquired by whitefly and the possibility for virus transmission are affected by the host plants, the special protein of geminiviruses as well as the GroEL proteins synthesized by endosymbionts of the vector. Geminiviruses may have favourable or unfavourable effects on the development, survival and reproduction of the whitefly. Whiteflies carrying tomato yellow leaf curl virus(TYLCV) show lower levels of survival and fecundity, while those carrying tomato mottle virus (ToMoV) show higher fecundity, compared with their counterparts. In addition, host plants infected by geminiviruses may increase their suitability to whiteflies.

 

The application of nuclear and mitochondrial gene sequences in the molecular phylogenetics of Aphididae (Hemiptera) is summarized, with a special focus on the scientific problems which they can resolve. Among the nuclear genes, sequences of EF-1α are used most widely, and they are fit for studying the phylogenies at genus or higher levels; nuclear rDNAs are used less in aphids’ phylogeny analysis, LWO is a new marker developed in aphids, and both of them are applicable for higher-level taxa above family. Among the mitochondrial genes, the most often used markers are COⅠ/COⅡ. 12S rDNA/16S rDNA, ND1, Cyt b and F-ATP6 are also used in Aphidinea phylogeny reconstruction. Combined analyses are performed between nuclear genes and mitochondrial genes, as well as among different mitochondrial genes. New genes should be explored, and “standard markers” need to be found in aphids. The prospects of molecular systematics in Aphidinea in the future are also discussed.

The yeast-like symbionts (YLS) were isolated and purified from the fat body of the brown planthopper, Nilaparvata lugens Stal (BPH) with different virulence reared on various rice resistant varieties. The 18S rDNA sequences of YLS from BPH with different virulence were analyzed and compared with the sequences of other fungi explored from GenBank, and a comprehensive phylogenetic tree was constructed. The phylogenetic analyses suggested that the YLS of BPH with different virulence belonged to the subphylum Ascornycotina, the class Pyrenomycetes, and had the closest genetic relationship with Hypomyces chrysospermus.

 

The insecticide resistance of field Musca domestica collected from 7 different populations of different habitats in seven administrative areas of Tianjin was determined by spot drip method and compared with the relatively sensitive strain in the laboratory. The individual carboxylesterase and glutathione S-transferase activity of populations from different areas were determined. The results indicated that the populations from different areas had different resistance levels to the insecticides tested. The resistance level to DDVP varied from 1.885 to 18.563 times, the resistance level to high effect cypermethrin varied from 1.071 to 14.071 times and the resistance level to propoxur varied from 1.071 to 7.499 times. The average activity of carboxylesterase of the field flies were higher than that of houseflies of the relatively sensitive strain in the laboratory. The distribution of carboxylesterase activity in both sensitive and field populations were obviously overlapped. The glutathione S-transferase activity of F₂ generations were quite different. The glutathione S-transferase activity of the field populations were higher  than that of the relatively sensitive strain in the laboratory, varied regionally from 2 to 4 times, which was in accordance with the diversity of the insecticide resistance levels of M. domestica in different areas in Tianjin.