The karyotypes and meiotic behavior of chromosomes in six species (Picromerus lewisi Scott, Dolycoris baccarum (L.), Lelia decempunctata Motschulsky, Menida lata Yang, Erthesina fullo (Thunberg) and Nezara viridula (L.)) of Pentatomidae were studied with male germ cells prepared on the slides air-dried and stained with Giemsa. All the 6 species had the typical diploid chromosome number of 14 for the family Pentatomidae and X-Y sex chromosome mechanism. But the behaviors of autosomes and sex-chromosomes during meiosis in the species investigated had characteristics at the species level. It may provide a useful clue in the study of pentatomid taxonomy and phylogenesis.

In this study the ability of gut extracts from the larva and adult of cotton bollworm, Helicoverpa armigera and armyworm, Mythimna separata to inhibit juvenile hormone (JH) synthesis was tested in vitro by radiochemical assay. The allatostatin (AS)like material that can inhibit JH synthesis in corpora allata (CA) occurred in the larvae and adult guts of these two species of insects. The inhibition of JH synthesis by 1 gut equivalent extract from larvae M.separata (43%) was greater than that from H. armigera (26%). Using 5 midgut equivalent of female or 10 midgut equivalent of male, the inhibition of JH synthesis achieved about 47% for the cotton bollworm and 35% for the armyworm. This indicates that the content of ASlike material in the gut from female is higher than that from male in both H. rmigera and M. separata. The inhibition of JH synthesis of CA was significantly higher by midgut extract than by hindgut extract in both insects. The inhibition of CA activity by midgut extract was completely re

The components and activities of microsomal P450 monooxygenases in 6th instar larva, pupa and adult were examined.The results showed that the levels of P450 and NADPH-P450 reductase were in the order of 6th instar larval midgut>pupae>adults. The contents of cytochrome P450 in pupa was similar to that in 6th instar larval fatbody,while the level of NADPH-cytochrome P450 reductase in the former was only about quarter as much as that in the latter.In adult microsome, the two components were undetectable.Compared with 6th instar larvae,the assayed activities were much lower in adult and pupa: the pnitroanisole demethylation was undetectable and aldrin epoxidation was 10 fold as that in 6th instar larva.

Using the nucleotide sequence of the VEF (viral enhancing factor) gene of Trichoplusia ni granulosis virus for reference, we designed a primer for PCR and amplified a specific fragment by PCR reaction. A recombinant plasmid pUC19-SF was constructed by cloning the PCR product which was treated with EcoRⅠ, BamHⅠ into pUC19. The PCR product was proven to be a fragment of the gene encoding the synergistic factor of Pseudaletia unipuncta granulosis virus (PuGV-Ps) by DNA sequencing. After labeling this fragment as a probe, the gene encoding of the synergistic factor was located in many restrictive fragments of PuGV-Ps genome by Southern blot hybridization.

The 2.5 kb fragment of enhancin gene in 3' terminal from Trichoplusia ni granulosis virus was inserted into vector pQE-31 and expressed successfully in Escherichia coli M15 (pREP4). The synergy of the expression product (P96) on Helicoverpa armigera nuclear polyhedrosis virus (HaNPV) against the 3rd instar larvae of H. armigera was also studied. The results indicated that the percentage of accumulated mortality of the larvae increased by 27.40%～34.50% on the 11th day postinfection and the median lethal time decreased at least by 1.9 days in HaNPV+P96 treated compared with those in HaNPV treated.

In Culex pipiens, resistance to organophosphate insecticides was recognized to be correlated with the increased nonspecific esterase activity. From a dipterexresistant mosquito strain (RD) of Culex pipiens pallens a special protein band was confirmed on SDS/PAGE spectrum. The identified band was not detectable in the susceptible strain(S) or the resmethrin-resistant strain (PY).This band represented a protein of MW 66 kD with pI value 4.6 ,which displayed carboxyesterase activity and accounted for 2.1% of the total extractable proteins. The purification of this protein was performed in turn by phenyl-sepharose (CL-4B), DEAE-cellulose (DE-5L) and FPLC column chromatographic procedures. Enzymological kinetics demonstrated a K_m value of 64.1 mmol/L and a V_max value of 249.8 mmol/(L·mg·min) with α-naphthol acetate as substrate. Dipterex could not inhibit its esterase activity, suggesting the 66 kD protein to be an A-esterase. Comparing with other esterase, it had lower K_m value and V_max value (except higher Vmax value than B-esterase). Further study exhibited that the 66 kD protein might play a role in insect resistance to organophosphate insecticide, mainly through sequestration effect. Nevertheless, the role of hydrolyzing activity at a minor extent could not be excluded.

There were virus-like filaments (VLFs) in the calyx regions of oviduct in the female wasp, Microplitis mediator Haliday. When an egg passed through the calyx region, the VLF attached to its surface and entered into the hemocoel of the host along with the egg. Transmission electron microscopy showed that an electron dense core of 35 nm in diameter was wrapped by one-layer membrane in the center of the VLF. The VLF exhibited a very long levogyrate structure with a diameter of 25 nm under negative staining. All of the wasp's eggs without VLFs were encapsulated in the hosts, early 3rd instar larvae of Mythimna separata while 88.2% of eggs were protected from encapsulation when they were covered by VLFs in the same host. The ability of VLF in protecting the wasp's eggs from encapsulation was different in the hosts at different stages. 64.7% and 9.5% newly-laid eggs was unencapsulated in the early 3rd and 4th instar host larvae respectively. These results suggested that the VLF only provided partial protection for the wasp's eggs and other factors (calyx fluid and venom, etc.) should make certain contribution to the immune system of the host, too.

The behavioural response of individual male Ancylis sativa Liu to synthetic sex pheromone components, E9-12∶Ac and Z9-12∶Ac was observed in a wind tunnel. The lures containing only E9-12∶Ac could stimulate some males (8.3%) to perform all the typical behaviours including exiciting, taking off, flying upwind,landing on the lure and exhibiting their hairpencils,while none of them showed any response to another component, Z9-12∶Ac.71.7%～76.7% of the males displayed their hairpencils in response to the mixture of these two components(E accounting for 60%～65%).The pheromone (E∶Z=6.5∶3.5) from 200 ng to 2 000 ng per lure caused more male response than that of 20 ng or 20 000 ng.

The LD₅₀，α-naphthylacetate（α-NA）esterase kinetics，α，β-NA esterase activity and IC₅₀ of dichlorvos（DDVP），phoxim and malathion to Del-R、2Cl-R and susceptible (SP) strains of houseflies were determined. The resistances of the Del-R and 2Cl-R to DDVP, phoxim and malathion were 0.966～7.190 folds as much as those of the SP strain，indicating a low resistance level to organophosphate insecticides in the pyrethroid-resistant houseflies. An obvious correlation of the carboxylesterase activity with IC₅₀ suggested that the carboxylesterase would play a significant role in the resistance to organophosphates in pyrethroidresistant houseflies.

The narrow sense heritabilities of larval tolerance to cyhalothrin and larval weight, and the genetic correlation between larval weight and tolerance to cyhalothrin in Helicoverpa armigera were evaluated using a half-sibling design of quantitative genetics methods. The results showed that narrow sense heritabilities were 0.2476±0.0248 for tolerance to cyhalothrin and 0.3613±0.1299 for larval weight in the cyhalothrin-resistant strain. The maternal factors did not associate with the resistance tolerance, but affected the larval weight. The genetic correlation between larval weight and the tolerance to cyhalothrin was significantly negative(r_a=-0.3416±0.1185，P<0.01).

Cantharidin, a terpenoid substance, is contained in a group of widely spreading insects—the blister beetles (Coleoptera: Meloidae) in the world. It has been used medicinally for its irritant proprieties, both in China and in the western countries for a long time. In China, in recent years, the clinical practice of cantharidin and its derivatives proved their curative effect on the primary liver cancer and some of other tumors to certain extent. In order to conserve and use the resource of Meloidae more effectively, an extensive survey of Meloidae and quantitative determinations of cantharidin in the adult of beetles were carried out. A total of 38 specimens in 9 species was collected on various host-plants from different districts in China. The cantharidin was isolated by HCl extraction of dry bodies of adults and quantitatively analyzed by GC with internal standard. The results showed that the maximum content of cantharidin was 2.932% of dry body in male Mylabris mongolica from Inner Mongolia Autonomous Region. All specimens contain cantharidin and the content of cantharidin was higher in the male than that in the female of the same species. In addition, the cantharidin content in the female collected after the copulation peak was higher than that before copulation peak, this suggested that transfer of cantharidin from male to female occurred during copulation.

Dynamics of the symbiote was monitored in different geographic and virulent populations of the brown planthopper (BPH), Nilaparvata lugens Stal, to determine its role in nymphal feeding selection, development and adult reproduction.Effect of symbiote on the activity of transaminases in BPH feeding on different resistant rice varieties was also examined. The results showed that the virulence of BPH to rice resistant varieties was closely related to number of the symbiote in BPH from the paddy fields, and abundance of the symbiote in BPH from Guangxi Province was markedly greater than that from Hangzhou and Longyou in Zhejiang Province, while no obvious differences in numerical dynamics of the symbiote were found among the three purified populations with different virulence to the resistant varieties (biotype Ⅰ, Ⅱ and Ⅲ) from the greenhouse in International Rice Research Institute (IRRI). Number of the symbiote reduced significantly in female adult of BPH biotype Ⅰ on resistant rice varieties IR26, Mudgo and ASD7 compared with that on susceptible rice variety TN1. The aposymbiotic nymph of biotype Ⅰ and Ⅱ treated by high temperature in egg stage preferred TN1 and ASD7 to Mudgo. The markedly lower nymphal survival rate, adult fecundity and activities of alanine transaminase and aspartic transminase, and longer nymphal duration were recorded in the three aposymbiotic biotypes than in control ones on susceptible and resistant rice varieties, however, the much greater changes occurred in the three tested biotypes when they fed on inadaptable resistant rice varieties. These results implied that the symbiote should play an important role in change of virulence of BPH population to resistant rice varieties.

Development，survival and reproduction of the cotton bollworm, Helicoverpa armigera (Hübner), reared on cotton，tobacco，tomato and hot pepper plants were monitored at (27.0±1.0)℃ with a 14L∶10D photoperiod in the laboratory. It was showed in the choice trials that the adults preferred ovipositing on the potted tomato plants while the newly hatched larvae liked staying and feeding on young cotton leaves which supported their growth better than the counterparts of the three other plants. The early sixth-instar larvae could utilize cotton boll and the reproductive organs of tobacco and hot pepper more effectively than tomato fruits.The larval survival rate was up to 83.6% on cotton as compared with only 7.3% on tomato. However, the durations of the larvae on cotton and tomato were almost the same and those on the two other plants significantly prolongated. The female moths from the larvae on cotton had the greatest egg production while fecundity of the moths from those on tobacco was very poor. The population trend index of this species on cotton was around 14 times that on tomato, the poorest food plant. Since H. armigera completed their life cycle when reared on the four food plants, all of them should be its host plants although tomato and hot pepper are less suitable.

The sex pheromone components of Dendrolimus punctatus consists of （Z，E）-5，7-dodecadienyl，（Z，E）-5，7-dodecadienyl acetate and （Z，E）-5，7-dodecadienyl propionate．To reduce isomerization and oxidation of above conjugated diene compounds，pheromone baits of different formulations and substrates were made and tested for their trapping efficiency in the field．In the 19 day-test，the trapping efficiency of natural rubber baits did not increase even if they were replaced every 5 days．Similar results were obtained with silicon rubber baits．Moreover，other baits such as adding an antioxidant （topanol CA）or a high purified pheromone did not give better trapping efficiency than the natural rubber ones．However，the baits formulated with compounded rubber septa attracted males twice as many as that by the natural rubber bait. After the field test， only 12%～16% of the pheromone components were isomerized in the compounded rubber baits，while 69%～87% isomerization occurred in the natural rubber baits．The residues of pheromone components and their isomers in the compounded rubber baits were four times as much as that in the natural rubber baits．These data suggest that higher trapping efficiency of the pheromone baits formulated by compounded rubber septa was due to the increase in the stability of the pheromone conjugated diene components and the lower but more constant releasing rate of the pheromone in these dispensers．

Changes in collembolan community structure were investigated respectively in the litter under the three species of trees,Cyclobalanopsis glauca (Cg), Pinus massoniana (Pm) and Quercus acutissima (Qa) in the same forest ecosystem during decomposition of the litter from April 1993 to April 1995.The decomposition process of Cg litter consisted of three phases:leaching phase,lasting from start of the experiment to the 7th month;immobilization phase,from 7th to 16th month;and mobilization phase,from 16th to 24th month.On the other hand,there were no such distinguishable phases during the observing period in both Pm and Qa litter.The greatest collembolan abundance and diversity index occurred in Cg litter. According to their occurring patterns during the litter decomposition, the collembolan species could be recognized as following three categories:the earlier colonizers (A), the later ones (B) and the long-term colonizers or those appeared only in the middle stage ©. Tomocerus sp., Isotoma sp. And Homidia hangzhouensis in the category A, and Folsomia octoculata, Pseudosinella sp. and Folsomina onychiurina in these litter category were shared by the 3 types of litter respectively. There were no common species in the category C.

The species of the genus Hedma Dumont are widely distributed in the Palaearctic, Ethiopian and Oriental Regions, with seven species known worldwide up to date. The present paper reports this genus for the first time from China and describes one new species injurious to Lycium barbarum Linn., Hedma lycia sp. Nov.. The species of the world are also listed.The type specimens are deposited in the Department of Biology, Nankai University, Tianjin, China.

A species of Aturinae, Aturidae, from Nei Mongol Autonomous Region is described as new to science: Aturus hexgonus sp. nov.. It is the first record of the subfamily Aturinae from China. The location patterns of glandularia and ocularia in the new species are described and illustrated in details.

Aphid sex pheromone is released from oviparae of female aphid from their hind tibiae and received by male aphid's secondary rhinaria on their antennae. A number of aphid sex pheromones comprised of a synergistic mixture of the monoterpenoids (-)-(1R, 4aS, 7S, 7aR)nepetalactol and (+)-(4aS, 7S, 7aR)nepetalactone in different ratios. This paper reviews the aphid sex pheromone work. The following aspects are included: (1) the composition of aphid sex pheromone. (2) secretion and aception of aphid sex pheromone. (3) the role of aphid sex pheromone in aphid species isolation.

The peptides eclosion hormone(EH) and ecdysis-triggering hormone(ETH) trigger ecdysis behaviors and other physiological changes which occur at the end of the molt. EH is synthesized in a discrete set of cerebral neurosecretory cells, and is released into the central nervous system and into the hemolymph in response to the declining ecdysteroid titers. ETH is released from the Inka cells,a component of the segmentally paired epitracheal glands,and acts directly on the CNS to trigger preecdysis and ecdysis behavior. Accumulating evidence suggests that EH is present in all insects and may provide a general hormonal mechanism to regulate ecdysis.