Viruliferous cotton aphids, Aphis gossypii, were treated with post-acquisition fast in the air to study cucumber mosaic virus (CMV) retention in the aphid and consequent transmission on the melon, Cumumis melo. Transmission efficiency was negatively correlated with fasting duration. The 10-min inoculation processes of fasted and non-fasted aphids were studied with electrical penetration graph (EPG) technique to search the behavior events responsible for the reduction of transmission efficiency. The total number of potential drops and the probing time before the 1st pd were usually considered as two important behavior variables correlated with transmission efficiency; however, no significant difference was found between fasted and non-fasted aphids. Fasting treatment significantly decreased the durations of sub-phase pdⅡ-1and pdⅡ-2. Further analysis suggested that the duration of pdⅡ-2 was probably a behavioral factor correlated with the virus transmission. The related behavioral mechanism was discussed. The 5 pd acquisition method was first used in virus acquisition research and a significantly higher transmission efficiency (78.6% vs 46.40%, P＜0.0001) was obtained compared to the traditional 5 min acquisition method.

The physiological mechanism of over-compensation in cotton plants, Gossypium hirsutum, for simulated infestation of the cotton bollworm, Helicoverpa armigera, on early squares was studied. Removal of 8 early squares by hand from each plant gave 13.4% more bolls than the control, and the increase in the bolls on the 6th and higher fruiting branches of treated plants contributed more to the increase of total bolls. Physiological determination showed that soluble sugar and starch contents in treated cotton leaves increased, while content of total free amino acids decreased. Increase in total leaf area (8.5%-28.1%) and photosynthetic activity (3.6%-6.7%) suggested they could be important reasons for the overcompensation observed in the treated plants, which resulted in higher productivity.

Obvious pathological changes in the midgut of the orient armyworm, Mythimna separata and the diamondback moth, Plutella xylostella were observed following treatment with cantharidin. The microvilli were sloughed off, goblet cell cavities enlarged, their projections sloughed off and the plasma membrane disappeared. Mitochondria swelled irregularly and their cristae fractured and become fuzzy. The cisternae of rough endoplasmic reticulum swelled obviously and the ribosomes denuded. The cell nucleus swelled and chromatin became concentrated. All the above observations show that cantharidin acts on the midgut membrane system.

The distribution, movement and metabolism of vitamin B₆ (VB₆) compounds in the silkworm, Bombyx mori, were studied in larvae reared on a semisynthetic diet, in which there was no mulberry powder and vitamin-free casein was the protein source. With the increase in the pyridoxine hydrochloride (PN-HCl) content of the diet, pyridoxine (PN) accumulated, and the content of pyridoxal (PL) increased in the larval body. However, the contents of (PLP) and yridoxamine 5'-phosphate (PMP), both of which are the coenzyme forms of VB₆, remained almost constant. PN absorbed by the midgut was first diffused into the hemolymph and then distributed to other organs by active transport. PN was first phosphorylated to pyridoxine 5'phosphate (PNP) by PL kinase, which was then oxidized to PLP by PNP/PMP oxidase in every larval organ except hemolymph. The transportation system of PLP, in which PLP binds to albumin, in the mammalian blood does not exist in silkworms. It is thus thought that the distribution, movement and metabolism of VB₆ compounds are different from those of mammals, and these are the reasons why almost no larvae could reach the next instar when newly molted larvae were reared on a VB₆ deficient diet.

Juvenile hormones (JH) Ⅰ,Ⅱ and Ⅲ can be effectively separated by traditional normal phase high performance liquid chromatography (NP-HPLC), but their metabolites and analogues can not be clearly separated by this method. We have recently modified a method of reverse phase high performance liquid chromatography (RP-HPLC). This modified method can be used to separate not only different juvenile hormones, but also a variety of juvenile hormone metabolites and analogues, qualitatively and quantitatively. Trace amounts of radiolabeled juvenile hormone, which was synthesized and secreted by the in vitro incubated corpora allata (CA), could be separated by both NP-HPLC and RP-HPLC methods. Moreover, the RP-HPLC can be used to separate radiolabeled juvenile hormone metabolites and analogues, in both in vivo and in vitro conditions, as well as to measure juvenile hormone levels in the hemolymph.

Resistance to lambda-cyhalothrin in the beet armyworm, Spodoptera exigua (Hübner), collected from Jiangpu County, Nanjing, Jiangsu Province was determined by three bioassay methods. The results indicate that the sequence of resistance levels was topical application for 3rd instar larvae (5 499.5-fold) and 5th instar larvae (3 973.2-fold)＞leaf-dip method for 3rd instar larvae (1 041.6-fold)＞leafsandwich method for 5th instar larvae (24.7-fold). Therefore, the resistant strain of S. exigua has a resistance level obtained by way of contact toxicity at least 160 times than that of stomach toxicity. After 8 h treatment the results indicate that the rate of uticular penetration of ¹⁴C lambda-cyhalothrin in 5th instar larvae of the resistant strain was only about 55.5% of that in the susceptible strain. It is safe to say that delayed cuticular penetration is an important mechanism responsible for this resistance.

The resistance to methamidosphos and methomyl and the effect of synergists on the insecticides in susceptible (S) and resistant (R ) strains of Diaeretiella rapae(Hymenoptera: Aphidiidae) were detected using the residual film method. The kinetic parameters of acetylcholinesterase (AChE), the activity of detoxication enzymes in D. rapae and its host Lipaphis erysimi (Homoptera: Aphididae) and the inhibition of synergists on enzyme activities in D. rapae in vivo were also investigated. The results show that compared to the susceptible strain, resistance to methamidosphos and methomyl was 5.6-fold and 9.1-fold respectively in the field D. rapae collected from Fuzhou, Fujian Province, China. Obvious synergisms of piperonyl butoxide (PB), triphenyl phosphate (TPP) and diethyl maleate (DEM ) to these insecticides were found in D. rapae, the synergism of PB being the highest. The synergisms of PB to the two insecticides In the R strain of D. rapae were significantly higher than those in the S strain. PB, TPP and DEM could not inhibit AChE activity, but strong inhibition of CarE activity was caused by PB and TPP, and GST activity by DEM . The apparent Michaelis-Menten constant (K_m) and maximal velocity V_max) of AChE and the activities of carboxylesterase (CarE) and glutathione S transferase (GSTs) in the S strain were similar to those in the R strain, but the values of the bimolecular rate constant (Ki) in the S strain of D. rapae were far higher than those in the R strain of D. rapae. In addition, a comparison of kinetic parameters of AChE and the activities of CarE and GSTs between D. rapae and L. erysimi were conducted. The results indicate that the resistance mechanism to methamidophos and methymol in D. rapae is related to AChE insensitivity and detoxication enzymes.

The temporal-spatial variation in efficacy of transgenic Bt cotton leaves from different nodes of the main stem and in different growth stages against neonate larvae of the cotton bollworm, Helicoverpa armigera (Hübner) were determined using the leaf-feeding method. The effects of leaves from both lateral branches of cotton in the field and seedlings in laboratory grown under different weather conditions on the neonates of the cotton bollworm were examined. Results show that efficacy of the leaves from the 2nd to 10th nodes on the main stem of Bt cotton R₁₉-137 was the highest, killing 97.0%-100% of larvae after 5 d feeding with 1.0-1.1 grades of leaf damage; the efficacy of the leaves from the 11th to 16th nodes decreased significantly with mortalities of 35.6%-67.6%, and survivors mainly in the 2nd instar. When the leaves from lateral branches of cotton in late July and late August were tested, mortalities of 30.9%-44.9% and 10.0%-30.0% occurred, respectively, indicating further decline of the control efficacy. The experiments also show significant influence of weather conditions, under which the Bt cotton grew, on the control efficacy of Its leaves. The possible reasons for temporal-spatial variations in efficacy of Bt cotton leaves against the cotton bollworm and the importance of weather conditions in Bt cotton application were discussed.

Longevity and weight gain of brachypterous females of Nilaparvata lugens that had emerged within 24 hours were investigated on two rice varieties,a susceptible variety TN1 and a resistant variety Mudgo, at 28±1℃. A positive correlation was detected between mean weight gain and longevity of females on Mudgo. Individuals that lived less than 7 days lost weight over their lifetime, while those living more than 7 days significantly increased in weight.Furthermore, the longevity, fecundity and weight gain over 1-4 days of newly emerged macropterous females were studied on TN1 and Mudgo, and positive correlation was also found to exist between these three parameters in females on Mudgo. Among them longevity and weight gain better reflected the virulent capability of individual females, and thus could provide an index of Individual virulence. Based on these results, it was proposed that newly emerged females on Mudgo that could survive over 7 days, or had a weight gain of more than 0.1mg within the initial 4 days should be defined as virulent.

To understand the ecological effects of mass-releasing Trichogramma chilonis in cotton fields, the biological control effects of this parasite were examined in two transgenic Bt cotton fields: one in which T. chilonis had been released and one in which it had not; and three non-transgenic cotton fields: one in which T. chilonis had been released in conjunction with chemical pesticides (IPM field), one with chemical pesticides only (chemically controlled field), and a natural control field as the control (no T. chilonis release or pesticides), in Nanpi County, Hebei Province, 1998－2000. The results show that: (1) natural parasitism in both types of cotton fields gradually increased from 13.3%－14.3% in the second generation to 26.7%－28.2% in the third generation and 60.8%－61.4% in the fourth generation. (2) In the IPM field, a second release of T. chilonis achieved a parasitism rate in the second generation of the cotton bollworms of 46.4%, an increase of 33.1% and 32.1%, compared to the non-release transgenic Bt and pesticide fields. In the transgenic Bt cotton field in which T. chilonis had been released, parasitism of the third generation of cotton bollworms reached 73.7%, similar to that in the IPM field and an increase of 45.5%, 61.8% and 47.0%, respectively, compared to the nonrelease transgenic field, and the pesticide and control fields. Parasitism of the fourth generation of cotton bollworms was, except for the pesticide field (52.1%), in excess of 60.0% in all other fields. (3) Parasitism in the pesticide field was 5.5% in the second generation and 11.9% in the third generation, a decrease of 8.8% and 14.8%, compared to the transgenic field in which T. chilonis had been released, and 40.9% and 56.2% compared to the IPM field. Releasing T. chilonis one day before using insecticides was associated with a parasitism rate of just 12.5%, while releasing T. chilonis two days after using insecticides was associated with parasitism rates of up to 45.6%. (4) Compared to the IPM field, the total number of cotton bollworm larval and buds and bolls injured per 100 plants in the pesticide field decreased by 74.8% and 73.8%, the total number of predators increased by 63.0%. The total number of cotton bollworm larval, and buds and bolls injured in the transgenic Bt cotton field in which T. chilonis was released decreased by 61.8% and 33.3%, compared to the non-release transgenic Bt field. Compared to the pesticide field, the total number of cotton bollworm larval, buds and bolls injured, and the use of insecticide in the IPM field, decreased by 29.7%, 43.4% and 60.0%, while the total number of predators increased by 63.0%. (5) The ratio of predators/phytophagous pests was 0.47 in the non-release transgenic Bt field, 0.30 in the IPM field, 0.24 in the pesticide field. The above results indicate that mass-release of T. chilonis can greatly enhance control of the cotton bollworm in both transgenic and non-transgenic cotton fields.

In order to evaluate biocontrol effect of an invasive pest, the fall webworm Hyphantria cunea, by the parasitoid Chouioia cunea (Hymenoptera: Eulophidae), life tables of four generations of the pest were consecutively studied for two years in Yantai, Shandong Province. Two experimental sites were selected where the fall webworm was still a big problem but not so serious as some years ago. In one of the sites the parasitoid was released twice in each fall webworm generation , at the beginning and peak period of pupation, while the other site served as the control. The average data of observations for the 1st generations of the fall webworm in two years were combined to make one life table for the test site and the average data of the observations for the 2nd generation of fall webworm were used to make another life table. Similarly, the average data of observations from the control site were used to make two other life tables. The results show that the trend indexes of population (I value) of 1st and 2nd generations of the fall webworm at the test site, 0.29 and 0.14 respectively, were significantly lower than that at the control site, 8.74 and 4.48 respectively. The pest population clearly declined at the test site and appeared to have been effectively controlled by the parasitoid.

The relationship between the first appearance in spring and seasonal distribution of Culex tritaeniorhynchus and the meteorological conditions in Fengxian District, Shanghai was studied using field survey data collected with light traps (from 18:00 to 06:00) in pigsties every night since from March 1 to June 30 in 1982-1992 and 2001-2002. Results of correlation contrast analysis, statistical analysis and weather chart analysis revealed that the seasonal distribution of C. tritaeniorhynchus can be divided into three stages: the first appearance date,the seasonal increase period and the mixed occurrence period. The temperature conditions at the first appearance of C. Tritaeniorhynchus were as follows: on the day of the first appearance and the day before the first appearance of C. tritaeniorhynchus, the mean daily temperature was over 11℃ and the cumulative temperature was over 25。5℃; or over an arbitrary three day period from two days before the date of first appearance to the day after the first appearance, mean daily temperature was over 11℃ and the cumulative temperature was over 34.0℃. The density of C. Tritaeniorhynchus (Y₁) over 5 day periods during the seasonal increase period was significantly positively correlated with mean daily temperature （X₁）; the univariate regression equation is Y₁= -9.3534+0.7217X₁ After the mean daily temperature over five days exceeded 18℃ (the mean date was 3 May), the density of C. tritaeniorhynchus entered the mixed occurrence period. Overall, close correlation exists between the seasonal distribution of C. tritaeniorhynchus and the mean daily temperature, wind direction and change of S-system. Dates on which sudden increases in C. tritaeniorhynchus were recorded were related to the movement of weather fronts. The density of C. tritaeniorhynchus increased markedly when the mean daily temperature over five days >18℃; this was an important temperature index for the beginning of the peak period. Theresults also point to the possibility of a northward migration pattern of C. tritaeniorhynchus in spring and early summer.

This paper deals with polyethism in the Formosan subterranean termite, Coptotermes formosanus Shiraki. Experiments showed that the aged workers carried out most tasks in the colony and played important roles in the maintenance of the society. Also the castes were an important factor influencing the division of labour. In nutrient trophallaxis, the soldier was a very important caste enjoying the special right to get the food from workers; nymphs had no foraging ability and also lived on food from the workers.

Statistical analysis of 11 math-morphological feature (MMF) (such as area, perimeter, etc.) from images of 23 species of insects of the Pentatomidae, Coreidae, Noctuidae, Saturniidae, Pieridae, Melolonthidae Rutelidae and Cerambycidae families indicates that the ranked reliability of MMF in the identification of insect families is, from high to low: (roundness, eccentricity)>(area, perimeter, X-length, sphericity)>(Y-length, circularity)>(form factor, lobation)>hole number. From the perspective of mathematical morphology, the kinship between the Nuctuidae, Saturniidae and Pieridae can be ranked as follows: Nuctuidae and Pieridae> Saturniidae and Pieridae> Nuctuidae and Saturniidae. Kinship between the Melolonthidae, Rutelidae and Cerambycidae can be ranked as follows: Melolonthidae and Cerambycidae> Rutelidae and Cerambycidae> Melolonthidae and Rutelidae.

A key is provided for the identification of ten genera of the world-wide subtribe Rhopalosiphina. One species, Schizaphis hypersiphonata Basu, (1969) 1970 was recorded for the first time in China. Studied specimens are deposited in the Zoological Museum, Institute of Zoology, Chinese Academy of Sciences (IOZ), Illinois Natural History Survey, University of Illinois, USA (INHS), Department of Agriculture, United States (USDA), and British Museum (BMNH).

This paper deals with the 20 species of Syntypistis Turner found in China, including one new species, Syntypistis melana Wu et Fang, sp. Nov., and two new records for China, Syntypistis hercules (Schintlmeister, 1997) comb. Nov. and Syntypistis defector (Schintlmeister, 1997) comb. Nov. The male genitalia of the new species and the newly recorded species are illustrated. A key to the Chinese species is provided.

Five Chinese species of the genus Calycomyza Hendel are recognized, of which one new species, C. chinensis sp. Nov. is described and illustrated; C. solidaginis (Kaltenbach) is newly recorded from this country. A key to the species is provided.

Strobilomyia flies are major pests of the cones and seeds of conifers in the Far East. In this region, this apparently monophyletic genus includes 20 species whose larvae specifically develop in the cones of Larix, Abies and Picea. The highest diversity is observed in larch in Northeastern China where the cone resource is shared among seven fly species. However, the precise knowledge of the specific distribution, life cycle and economic impact of Strobilomyia spp. Has been hindered by taxonomic uncertainties. This paper reviews this important group based on some 108 publications on cone flies in the Far East, and presents additional original data obtained in Central Siberia, Kamchatka, Heilongjiang and northern Yunnan provinces. The fly species related to larch, fir and spruce are successively reviewed according to a common scheme including: distribution, host species and identity; morphology of adults, eggs, larvae and pupae; biology and phenology; damage importance; and forecast and control methods.

Most insecticides are potent neurotoxicants that act on various targets in the nerve systems. Organophosphorus (OP) insecticides inhibit not only acetylcholinesterase activity and acetylcholine (Ach) receptor function, affecting the release of Ach from presynaptic membrane, but also the development of nerve cells, indicating the noncholinergic effects of these insecticides. Some of the OP insecticides can induce delayed neurotoxicity in mammals. Neonicotinoid insecticides, agonists of nicotinic acetylcholine receptors (nAChRs), act on the alpha subunit of the receptors, which increases their postsynaptic potential. These kind of insecticides show selective toxicity for insects over vertebrates because they act on different subunits of the nAChRs from those in vertebrates. Pyrethroid insecticides act mainly on the sodium channels, keeping the channels open leading to the blocking of signal transmission. In addition, pyrethroids can inhibit the activity of calcium channels and interfere with the release of glutamates and dopamines. The selective toxicity of pyrethroids for insects probably resulted from configuration differences of the sodium ion channels in nerve cells between insects and mammals. Avermectin insecticides can cause the release of gammaaminobutyric acid (GABA) and enhance the affinity of GABA with GABA receptors, leading to chloride influx and postsynaptic hyperpolarization. Owing to the difficulty of penetrating the blood brain barrier to bind to GABA receptors in central nervous system (CNS) of vertebrates, the toxicity of the avermectins to vertebrates is much lower than to insects. Spinosad insecticides act not only on the nAChRs in the CNS of insects, inducing long-term release of the Ach, but also on the GABA receptors, affecting the function of GABA gated chloride ion channels.

Bacillus thuringienses (Bt) is a widely used bio-insecticide. The Bt receptor protein is very important to the toxicity expression of Bt in insects, and it has been suggested that change of binding ability between this receptor protein and Bt may be the main mechanism of Bt resistance. In this paper, the separation, identification and binding dynamics of the insect Bt receptor protein, and the relationships between Bt toxicity, Bt resistance, receptor proteins, and molecular nature are reviewed.

This paper describes the spermatozoon ultrastructure in Mecopoda nipponensis (De Haan). Spermatozoon of this species were examined by transmission electron microscopy after double fixation of live material in glutaric-aldehyde and osmic acid. Its acrosomal complex lies to the side of the flat, dense nucleus and partially embraces it. Two broad bean shaped accessory bodies are located laterally to the axoneme, which is of a typical 9+9+2 pattern. Two almost completely crystallized mitochondrial derivatives are oval in cross-section. There are three connecting bands between mitochondrial derivatives and axoneme. Two flat membranous cisterns close to mitochondrial derivatives are S-shaped in cross-section. A character peculiar to this species, an additional bi-layer membrane, appears around organelles of the tail in some cross-sections.