In Culex pipiens, overproduction of nonspecific esterases is a common mechanism of resistance to organophosphate insecticides. The esterases are attributed to closely linked loci named A and B, and overproduction of all esterases B is due to gene amplification. In order to determine whether the esterase B1 identified by electrophoretic studies in Culex pipiens mosquitoes from different countries is over-produced due to the amplification of the same DNA haplotype, the amplified region encompassing the structural esterase B1 gene was characterized by restriction mapping and RFLP. The same amplified haplotype was found in mosquitoes with an esterase B1 protein, independently of their geographical origin- French Guiana, Venezuela, Puerto Rico, California and China. Large variations in amplification levels were observed. In addition to the highly amplified 2.1kb fragment, EcoRI digestion led to two other restriction fragments of low amplification in mosquitoes from the Americas but notfrom China. It is concluded that B1 amplification has a unique origin, either in America or in Asia, and has subsequently spread on a large scale by migration. This migration is more limited than that of A2-B2 esterases, since B1 is confined to the Americas, Carribean and part of China, whereas the A2-B2 distribution now includes the Americas, Carribean, Asia, Africa, Pacific islands and Europe.

The effects of fenvalerate resistance on fitness in Helicoverpa armigera(Hubner) were evaluated in terms of developmental and reproductive characteristics.Life tables of Fen-R strain (fenvalerate-resistant) and S strain (susceptible) were also constructed to determine relative fitness by net reproductive rate (Ro). The results indicated that Fen-R strain possessed reproductive disadvantages including percentage of females mated, lower mean number of eggs per female laid and decreased percentage of eggs hatching when compared with the S strain. No developmental defect of Fen-R strain was observed. The Fen-R strain was calculated to have a fitness value of 0.69 relative to the susceptible S strain.

The diamondback moth (DBM), Plutella xylostella L, is one of the most destructive pest of crucifer crops in Guangdong Province, China. The resistance of field strains of DBM from Shenzhen (SZ) and Guangzhou (GZ) city of Guangdong Province to conventional microbial insecticides has been investigated. Results showed that the strains of SZ and GZ had resistance to synthetic pyrethroids, organophoshorus insecticides, carbamates as well as insect growth regulators, but only the strains of SZ showed resistance to microbial insecticide (B. Thuringiensis). Fenvalerate was greatly synergized with piperonyl butoxide (PB) or o,o -diethyl-o-phenyl-thiophosphate (SVI). An addition of PB, SV1 and TPP (triphenyl phosphate)to microbial insecticide BT resulted in no synergism, indicating that the resistantmechanism of DBM to BT does not include microsomal oxidation of MFO and esterases. Susceptible of DBM would obtain resistance to Dipel (B. thuringiensis var. Kurstaki) soon, when every generation was bred with Dipel under laboratory condi-tion (23℃-30℃ , L: D =12:12). The LC₅₀ of F₀, F₅ F₁₂ and F₁₈ were 30.33, 298.00,695.33 and 1077.33mg/L, respectively, the LC₅₀ of F₁₈ was 35.5-fold as that of F₀.On the other hand, during the 20 generations of rearing without insecticide pressure,recovery of sensitivity to BT was detected, so was the recovery of sensitivity tochemical insecticides, but the recovery of sensitivity to insect growth regulators (chlorfluazuron) and synthetic pyrethroids was very slow. Fortunately, no crossresistance was found between the chemical and microbial insecticide (BT) used.

The authors conducted qualitative and quantitive studies on spermatogenesis and spermiogenesis in Agrotis ypsilon and Mythimna separata with use of light and electron microscopes. At the same time, the effects of risen temperature were also studied. The results are briefly summarized as follows: There were eupyrene and apyrene sperms in A. ypsilon and M. separata after spermatogenesis. When the rearing temperature rose above 32℃, a lot of abnormal spermatid cysts appeared and spermiogenesis was arrested. In addition, the nucleus and flagellum of eupyrene spermusually shortened and a large amount of flagellum microtubles could not be produced under this temperature. But the risen temperature (<32℃ ) had no effects on dichotomous spermatogenesis and the shift of spermatogenesis from eupyrene sperms to apyrene. This phenomenon implies that the migratory flight of A. ypsilon and M.Separata in summer season from south toward north is an adaptive behavior.

A comparative study of the structure and characteristics of compound eyes is made with light- and electro-microscopes on two sister species in Chrysomelidae:Altica fragariae, which is a shade-habiting insect, inhabit in shade and concealed niches, and A. arnpelophaga, a light-habiting insect living in sunny and open places.Both species possess ovoid compound eyes with diameter of 0.3mm in the longdirection on the upside laterad of the head. Each ommatidium contains a double convex corneal cone, four semper cells and seven retinula cells, and is surrounded by two principal pigment cells and eleven or twelve secondary pigment cells. The rhabdomeres of six of the seven retinula cells join together and make a hexagonal rhabdom frame with another rhabdomere at the middle. Each rhabdomere is nearlyrectangular in shape and is filled with microvilli arranging nearly in parallel to each other. Aside from these similarities, there are some obvious differences between the two species. The ommatidium number in each compound eye is about one hundred fifty in A. fragariae, but two hundreds in A. ampelophaga. The radius of curvature of the compound eye is in the ratio of one (A. fragariae) to two (A. ampelophaga). The ratio of rhabdom occupation to whole retinular area on A. fragarive and A.Ampelophaga are about 37% and 25% respectively in the cross section of the middle parts of rhabdoms. The possible functional significance of the structure differences is discussed.

To bring the pest control activity of predacious natural enemies into good play on cotton, a series of field investigations and indoor tests were carried out for getting their population dynamics along with the development of cotton in eight different cotton agroecosystems, and the energy currency parameters of the populations of predacious ladybirds, bugs, spiders and whole predators were calculated according to a unified energy unit. The characteristics of energy intake and exploitation of each predacious natural enemy population in different types of cotton fields with different sowing times, intercropping and tillage systems were analysed and compared with each other. The dynamic regularities of pest control activities and the functions and locations of different predacious natural enemies in different cotton agroecosystems were summarized and evaluated.

The external morphology of the female and ootheca and internal structures of digestive, excretory and reproductive systems of Polyphaga obscura Chopart, a species belonging Polyphagidae of important medical use in China found only in southern part of Akesu District, Xinjiang Uygur Autonomous Region, was studied. The results showed that in the absence of male specimen, the morphology of oothecacan be used as the basis for identifying the species of olyphaga, and it is confirmed that Polyphaga obscura is a valid name. Based on the morphology and behavior, we regard Polyphaga Spp. As cave dwellers with earlier history than Eupolyphaga sinensis Walker.

Lema scutellaris has one generation per year and overwinters as adult.This insect shows a monophagous habit feeding only on Commellina communis, butnot other plant species. As shown in our feeding tests, it refuses either the same or the closely-related plant families or genera. The occurrence of the insect is synchronic with the seedling stage of Commellina communis. Feeding of the larvae is coinciding with the richly branching feature of the plant. The nutritional location where the insect feeds on is highly correlated with the distribution of the muscouscells of the plant and the cells' sugar contents.

The present paper reports two new species of the genus Goniogryllus from Shaanxi, China, and a new record of the female G. emeicus Wu et Wang from Emeishan, Sichuan, China. All type specimens are deposited in the Institute of Zoology, Shaanxi Normal University.

In the present paper, one genus and two species of Pamphagidae fromNingxia are described as new to science. All the type specimens are kept in the Institute of Zoology, Shaanxi Normal University.

Monochroica gen. Nov., a new genus belonging to group Phylus of Phylinae Phylini of Hemiptera-Heteroptera is here erected, based on a new species -M.Alashanensis Qi et Nonnaizab, sp. Nov. Meanwhile, genus Dichrooscytus Fieber is noted with a decription of a new species -D. helanensis Qi et Nonnaizab, sp. Nov.. Themeasurements in the description are in millimeters. All the type specimens are deposited in Collection of Department of Biology, Inner Mongolia Teachers' University.

The present paper deals with 7 species of Syrphus Fabricius, of which one species is described as new to science. A key to the known Chinese species is given.The new species is described as follows.

This paper reports two new. Species of Diptilomiopinae from China. Allmeasurements are in micra. The holotype and allotype specimens are deposited in Nanjing Agricultural University, and paratypes are deposited in Guangxi Agricultural University.

This review deals with the progress in the molecular study on the biologicalclocks in insects. Biological clocks represent a type of cellular regulation common to most eukaryotes. They are disturbed by certain mutations in insects. The genesdefined by certain of these mutations in Drosophila have been isolated. The mostimportant clock gene period has been studied in detail, including its structure,expression, regulation, etc. These investigations are revealing the molecular nature of biological clocks.

The wingbeat patterns and frequencies of insects tethered for flying were studied by PFS-1 strobotac and computer system. Fifty selected species belonging to 20 families, 8 orders were tested; the results showed that according to the movement of the fore-and hind-wings with regavd to the amplitude and frequency of wingbeating, the patterns may be divided into 3 main kinds and 7 types. Wingbeat frequency was closely related to the wing load and the development level of thorax muscles.