Determination of diel periodicity of sex pheromone release in three species of Lepidoptera by ‘closed-loop-stripping’

Summary By means of closed-loop-stripping and subsequent GC analyses the diel periodicity of release of (Z)-11-hexadecenyl acetate, (E)-8-dodecenyl acetate, and (Z)-9-tetradecenyl acetate, the main constituents of the respective sex pheromone blends ofMamestra brassicae, Cryptophlebia leucotreta andSpodoptera sunia females, was determined.Pheromones, 64. For the 63rd contribution we have taken from: Szöcs, G., Toth, M., Bestmann, H. J., Vostrowsky, O., Heath, R. R., and Tumlinson, J. H., Z. Naturforsch.42c (1987) 165; Pheromones, 62: Bestmann et al.¹³.     

Detection of toxic metabolites in the hemolymph ofBeauveria bassiana infectedSpodoptera exigua larvae

Highly active metabolites have been detected in the hemolymph of the lepidopteranSpodoptera exigua infected with the mycopathogen,Beauveria bassiana. A combination of phenyl sepharose and CM ion exchange chromatography was utilized to extract the active metabolites from infected hemolymph samples. The active in vivo metabolites, having a molecular mass greater than 10 KDa, were thermolabile and were inactivated by proteinase K. These metabolites were characterized by their ability to disrupt metamorphosis, killing treated larvae at the wandering or pupal stage. Additionally, injection ofS. exigua larvae with active samples caused a reduction in the number of filopodial-producing hemocytes. The biological activities and biochemical properties suggest that novel compounds are produced duringB. bassiana mycosis.     

Induction of nicotine in tobacco by herbivory and its relation to glucose oxidase activity in the labial gland of three noctuid caterpillars

Tobacco Nicotiana tabacum L. is a host plant ofHelicoverpa armigera (Huibner), Helicoverpa assulta Guenee and Spodoptera litura (Fabricius) (Lepidoptera, Noctuidae). The difference in leaf nicotine response to the feeding by these three larvae and the mechanical simulation of their feeding was examined by HPLC. Results indicated that nicotine induction was suppressed by H. armigera and H. assulta larvae feeding or by simulated damage treated with their labial glands extracts. The production of nicotine was also suppressed by the glucose oxidase from Aspergillus niger when it was treated on mechanically wounded leaf area. On the contrary, the nicotine production was stimulated by S. litura larva feeding or by simulated damage treated with its labial gland extract. Heat denature can not counteract the stimulation effect of the S. litura labial gland extracts to tobacco nicotine production. The glucose oxidase activity was detected in labial gland extracts of both H. armigera and H. assulta, but the activity in H. armigera was significantly higher than that in H. assulta. No glucose oxidase activity was detected in labial gland extracts of S. litura. It is shown that the glucose oxidase activity in labial glands of caterpillars plays an important role in the nicotine response to herbivory. The glucose oxidase was mainly contained in the labial gland of H. armigera larva, and had the highest activity at pH 7.0. D-Glucose was the optimal substrate of the glucose oxidase. Labial gland glucose oxidase activities varied daily during larval development with high activities found when larvae were actively feeding.     

Apoptosis of Spodoptera litura larval hemocytes induced by heavy metal zinc

By adding different amount of zinc into the artificial medium of the insect larvae, the zinc-induced apoptosis of the larvae haemocytes of the herbivorous insect Spodoptera litura Fabricius was investigated with flow cytometer. The results showed that the increase of zinc dose in the artificial feed led to the accumulations of zinc in the larval hemolymph and fat body, and more zinc was accumulated in fat body than in hemolymph. The apoptosis of hemocytes was significantly induced at high zinc concentration （1000 mg·kg^-1） in the insect diet, and the apoptosis rate was 63.63%, which was remarkably higher than that at control and lower concentrations （50--500 mg·kg^-1）. This suggests that the high dose of zinc in the artificial diet of S. litura larvae could induce the apoptosis of the larval hemocytes of S. litura.     

Nickel accumulation and its effects on the survival rate of Spodoptera litura Fabricius under continuous nickel stress

The artificial diets mixed with various concentrations of nickel were offered to the larvae of the phytophagous insect Spodoptera litura Fabricius for 3 generations. Nickel accumulations in the 6th instar larvae, pupae and newly emerged adults of the corresponding generations of S. litura were investigated by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), and the effects of nickel accumulations on the survival rate of S. litura were also evaluated by individual rearing. The results showed that nickel accumulated in the 6th instar larvae, pupae and adults of S. litura, and the accu- mulated nickel in all the tested developmental stages within a generation increased with the increase of the nickel doses in the treated diets and showed significant dose-dependent relationship with the nickel doses in the artificial diets. The results also indicated that the nickel accumulations in the 6th instar larvae, pupae, and newly emerged adults from the 3rd generation were higher than those from the 2nd generation, which were also higher than those from the 1st generation. Nickel concentrations in pupae and adults were significantly lower than those in larvae, which indicated that the excessive nickel might be excreted during metamorphosis. Furthermore, larval survival rate, pupation rate and eclosion rate of S. litura in the tested three generations all decreased with the increase of the nickel doses in the treated diets.     

SlNPV PK基因的部分序列分析

ＳｌＮＰＶ基因组ＤＮＡ的ＨｉｎｄⅢ－Ｘｂａ片段上含有部分的ＰＫ基因，ＳｌＮＰＶＰＫ的氨基酸序列与ＨａＮＰＶ，ＨｚＮＰＶＳｐｌｉＮＰＶ，ＡｆＮＰＶ，ＡｃＮＩＶ，ＬｄＮＰＶＰＫ氨基酸序列的同源性分别为４５％，４４％，８９％，３７％，３８％和３７％，其上含有蛋白激酶的特征序列ＩＶＨＡＮＤＶＫＬＥＮＶＬ。     

云南草地贪夜蛾区域生态防控思想与对策

云南是中国草地贪夜蛾（Spodoptera frugiperda）危害最严重的省份，统筹云南草地贪夜蛾区域防控对于全国草地贪夜蛾防控具有重要战略意义.作者提出并阐述了云南草地贪夜蛾区域生态防控思想，将云南草地贪夜蛾发生地划分为七大发生区，以边境防控、虫源地防控和通道防控作为典型案例，探讨了区域生态防控对策.研究将为制定云南草地贪夜蛾科学防控方案提供理论依据和科学指导.     

Growth inhibitory,insecticidal and antifeedant effects of some antileukemic and cytotoxic quassinoids on two species of agricultural pests

Summary Several quassinoids, obtained by isolation and derivatization fromSimaba multiflora andSoulamea soulameoides, were evaluated for growth inhibitory and insecticidal effects against the tobacco budworm (Heliothis virescens) and for antifeedant effects againstH. virescens and the fall armyworm (Spodoptera frugiperda). The relative activity of the quassinoids as insect growth inhibitors generally paralleled their known relative potency as antileukemic and cytotoxic agents.Phytochemical aspects of this work were supported by Contract CM-97295 with the Division of Cancer Treatment, National Cancer Institute, National Institutes of Health, Bethesda, Md. Insects were kindly supplied by the agency of the United States Department of Agriculture at Brownsville, TX.     

斜纹夜蛾前胸腺的生长发育研究

 通过解剖观察4龄至蛹期斜纹夜蛾前胸腺,对其形态特点和生长发育规律进行了研究,主要结果如下：发现斜纹夜蛾前胸腺由53个左右的圆形或椭圆型细胞成串组成,Y型,成对,外围包裹一层透明鞘膜,位于胸部第一气门的气管丛内;在斜纹夜蛾4龄到蛹期的发育过程中,前胸腺不发生有丝分裂,细胞数量基本恒定;前胸腺细胞直径在幼虫发育期间不断增大,斜纹夜蛾幼虫在4龄第1天的前胸腺直径为(28.80±0.47) μm,而到了6龄末期,则增加到(92.22±2.43) μm;幼虫期的斜纹夜蛾前胸腺细胞直径和虫体体质量呈显著相关,r=0.826,P=0.000,拟合曲线方程为Y=82.1X ^0.263;此外,幼虫期的斜纹夜蛾前胸腺细胞直径和虫体体长也呈现出显著相关,r=0.886,P=0.000,拟合曲线方程： Y=e^{(4.781-1.863/Z)}。     

红秋葵上斜纹夜蛾的发生规律及控制技术研究

研究了红秋葵上斜纹夜蛾的发生规律及控制技术。结果表明,斜纹夜蛾是红秋葵上发生的主要害虫,其自然种群数量随季节变动,在7—8月达为害的高峰,温度升高明显有利于其种群数量的增长．种群数量变动与温度呈密切正相关,其回归关系式为：Y。=17．4924＋0．2031X．-0．0005942X;;浓度为1gDW／l（10mL的柑橘、艾蒿提取物喷施后．药后3d的校正防效分别为83．69％、82．22％,其次是曼陀罗、蓖麻和蛇床子提取物喷施后,药后3d的校正防效分别为78．81％、72．96％和71．04％。