Host microhabitat location by stem-borer parasitoidCotesia flavipes: the role of herbivore volatiles and locally and systemically induced plant volatiles

The origin of olfactory stimuli involved in the host microhabitat location inCotesia flavipes, a parasitoid of stem-borer larvae, was investigated in a Y-tube olfactometer. The response of femaleC. flavipes towards different components of the plant-host complex, consisting of a maize plant infested with two or more larvae of the stem borerChilo partellus, was tested in dualchoice tests. The concealed lifestyle of the stem-borer larvae did not limit the emission of volatiles attractive to a parasitoid. A major source of the attractive volatiles from the plant-host complex was the stem-borer-injured stem, including the frass produced by the feeding larvae. Moreover, the production of volatiles attractive to a parasitoid was not restricted to the infested stem part but occurs systemically throughout the plant. The uninfested leaves of a stem-borer-infested plant were found to emit volatiles that attract femaleC. flavipes. We further demonstrate that an exogenous elicitor of this systemic plant response is situated in the regurgitate of a stem-borer larva. When a minor amount of regurgitate is inoculated into the stem of an uninfested plant, the leaves of the treated plant emit volatiles that attract femaleC. flavipes.     

The pheromone of the eastern tent caterpillar,Malacosoma americanum (F.) (lepidoptera,Lasiocampidae)

The pheromone system of the eastern tent caterpillar,M. americanum, has been identified as a mixture of (E,Z)-5,7-dodecadienal and the corresponding alcohol. Field data on the attractiveness of the aldehyde alone were not consistent, but mixtures of aldehyde and alcohol in varying proportions were attractive to males. Addition of small amounts ofE,Z acetate toE,Z aldehyde had no effect on male response, but larger amounts reduced trap catch. Traps baited withZ,E, E,E, orZ,Z aldehydes were not more attractive than blank traps. Pherocon IC traps fortified with extra adhesive and baited with lures consisting of 500 µg (E,Z)-5,7-dodecadienal with either 250 or 100 µg of the corresponding alcohol trapped as many as 100 males/trap/night with means of 15–20. Lures prepared from purified (94%E,Z) aldehyde and alcohol were more attractive than those prepared from unpurified (58%E,Z) materials.DeceasedMention of a company name or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture.     

Chemical correlates of α-tocopherol (Vitamin E) alteredMalacosoma disstria herbivory inFraxinus pennsylvanica var.Subintegerrinia,green ash

The antioxidant -tocopherol (vitamin E), applied in a basal trunk band to the green ash tree,Fraxinus pennsylvanica var.subintergerrinia, elicited an alteration of foliar feeding byMalacosoma disstria larvae (Lepidoptera: Lasiocampidae). The bioassayed effects were dependent on the dosage of elicitor, the time after elicitation, and the position in the tree. Leaves for chemical analysis were collected from trees receiving two dosages and at two intervals after elicitation. Compounds in the ethyl acetate extractables from the ash tree leaves were separated by TLC and HPLC. TLC separations showed differences in the nonhydrolyzed extractables attributable to elicitor dosage and time after elicitation. TLC-resolved differences were also evident among acid-hydrolyzed samples. HPLC-resolved profiles revealed eight peaks in the nonhydrolyzed extractables that were quantitatively negatively correlated with larval feeding preference between elicited versus control foliage on at least one of the two sampling dates. Results from this study and other investigations reported in the literature indicate that the antioxidant-tocopherol (vitamin E) can function as an environmental-stress elicitor of alterable defensive chemistry in green ash and other plants.     

毛毛虫形粗旦仿毛锦纶6纤维的生产工艺

对毛毛虫形粗旦仿毛锦纶6的生产工艺进行了研究分析,发现合理控制纺丝速度、纺丝温度、侧吹风、热辊温度和拉伸比等工艺参数,改进上油方式,可以生产出物性指标良好,并具有较好仿毛手感的粗旦仿毛锦纶6FDY。试验表明:纺速在4000~4300m/min,拉伸比1.1~1.3,热拉伸温度150~170℃,侧吹风速0.10~0.18m/s,下调上油位置,延缓上油时间,可以生产出外观好、染色均匀、性能指标好、仿毛手感好的粗旦仿毛锦纶6全拉伸丝。     

机器人控制系统

目前,移动机器人具有很大的开发空间。无线控制成为移动机器人必不可少的控制方式。机器人的机械结构决定了移动机器人的功能,由此来确定合适的驱动系统。再利用强抗干扰能力的无线收发一体传输MODEM模块PTR2000芯片,通过单片机对机器人关节步进电机和驱动电机进行控制,实现了数据的无线传输,来控制机器入的运作。     

Simultaneous determination of free ergosterol and ergosteryl esters in Cordyceps sinensis by HPLC

The caterpillar-shaped Chinese medicinal mushroom Cordyceps sinensis consists of the fruiting body (CsA) and the host caterpillar (CsB). Ergosterol is a principal sterol in fungi and can indicate the level of mycelia of C. sinensis. Ergosterol is present in two forms, as free ergosterol and esterified ergosterol, which have different physiological functions. The relative abundances of free to esterified ergosterol are different among the various species. In the present study, a gradient reversed-phase high-performance liquid chromatography (HPLC) method was developed for the simultaneous determination of free and esterified ergosterol in CsA and CsB of C. sinensis. The results showed that CsA and CsB had similar ergosterol compositions, but the level of ergosteryl esters in CsB was much higher than that in CsA, indicating that CsA and CsB might be in different growth phase or have different physiological functions for the growth and multiplication of C. sinensis.     

论导轨式爬架在高层施工中的应用

以太原市西华苑小区3号住宅楼工程为例,从导轨式爬架的爬升原理、性能指标、布置方案、安装、升降操作及安全保证措施等方面进行了研究论述,从而为导轨式爬架的推广应用奠定了基础。     

EBJ120掘进机行走机构的设计

以EBJ120型悬臂式掘进机为例,首先依据EBJ120型掘进机行走机构的组成和功能,介绍了其设计要求以及设计掘进机的主要技术参数。然后,确定掘进机行走机构的主要技术参数,最后对行走机构主要部件履带架等进行了设计和计算。该研究为掘进机的设计提供了指导。     

Are Chemical Compounds Important for Soybean Resistance to <Emphasis Type="Italic">Anticarsia gemmatalis</Emphasis>?

The identification and quantification of flavonoids (rutin and genistin) present in extracts of soybean genotypes, and their effects on the biology and physiology of Anticarsia gemmatalis Hübner (Lep.: Noctuidae) were studied. Analysis of covariance and bicoordinate utilization plots were used to remove the effect of feeding time from pupal weight and consumption as well as to separate pre- and postingestive effects of treatment on A. gemmatalis growth. Genotypes PI 274454, PI 227687, and “IAC-100” extracts in general, caused higher mortality, negatively influenced initial larval and pupal weight, and elongated larval cycle. Larvae fed on the “IAC-100” extract diet ingested larger amounts of food per unit of time, but were less efficient in its conversion to biomass. Leaf extracts of PI 227687 had the largest concentration of rutin (quercitin 3-O-rhamnosylglucoside), followed by PI 274454, and “IAC-100”; PI 74454 also had the highest genistin (genistein 7-O-glucoside) content. The susceptible cultivar “BR-16” showed only a kaempferol-based flavonoid in its chemical profile, indicating that after successive crosses, secondary compounds responsible for plant defenses were eliminated. Genotypes PI 274454, PI 227687, and “IAC-100” showed accentuated resistance characteristics and were considered inadequate sources for the development of A. gemmatalis. Considering rutin and genistin concentration in these genotypes, it is suggested that flavonoids are important factors conferring resistance to A. gemmatalis.     

Specificity of trail markers of forest and eastern tent caterpillars

Exploratory trails deposited on paper strips by the forest tent caterpillar (FTC),Malacosoma disstria Hubner, and the eastern tent caterpillar (ETC),M. americanum (Fabricius), as well as extracts of these trails, readily elicited interspecific trail-following behavior. In 2-choice tests involving simple Y mazes constructed from these paper strips, the caterpillars of both species preferred by approximately 31 the trails of the FTC. Studies involving whole colonies of the ETC maintained under nearnatural conditions in the laboratory, however, indicated that the trails deposited by successful foragers of the ETC as they returned to their tent from feeding sites were more attractive than the exploratory trails of either the ETC or FTC. The pronounced interspecific response of these congeners to each other's trails suggests that they utilize either qualitatively similar or identical trail-marking chemicals. Both species preferred their own trails to those ofArchips cerasivoranus (Fitch) (Tortricidae), providing the first evidence that more distantly related lepidopterous larvae utilize distinct trails.