Genetic variations in a population of herbivorous mites Tetranychus urticae in the production of the induced volatiles by kidney bean plants

Abstract

This study tested whether a population of herbivorous mites Tetranychus urticae exhibits genetic variation in the production of induced plant volatiles in kidney bean plants (Phaseolus vulgaris L.). We selected two T. urticae genotypes based on their dispersal behavior (early- and late-disperser) in two plant lines (Line-1 and Line-2). In both lines, plants infested by the early-disperser produced large amounts of induced volatiles after the spider mite population peaked on the plants, whereas those infested by the late-disperser emitted the largest amount of induced volatiles at the population peak. The possible manipulation of the production of herbivore-induced plant volatiles by herbivores is discussed.     

二斑叶螨危害对棉花应激防御酶活性的影响

探明二斑叶螨取食对棉花叶片内应激防御性酶活性的影响。在棉苗5-6叶期接种不同数量(10-40头)的二斑叶螨雌成虫,取食1-4 d后采摘不同处理的叶片,利用分光光度计测定过氧化氢酶(CAT)、过氧化物酶(POD)、多酚氧化酶(PPO)、脂氧合酶(LOX)和苯丙氨酸解氨酶(PAL)活性。结果表明二斑叶螨取食后,棉花叶片CAT活性显著升高,且随诱导时间的延长其活性变化呈先上升后下降的趋势,为害3 d时,10、20、H(每株接棉蚜跟叶螨各40头)头/叶的CAT活性达到最高峰,显著高于对照(P0.05);POD、PAL活性也随诱导时间的延长和螨口数量的增加呈上升趋势,为害4 d时达到最高峰;而PPO、LOX活性随着时间的增加呈现上升后下降趋势,且为害2 d时达到最高峰,仍显著高于对照(P0.05)。棉叶应激防御酶活性随着二斑叶螨为害时间与螨口密度的增加而增加,表明二斑叶螨的危害胁迫能诱导寄主植物产生一系列应激生化反应,不同的酶活性表现有所不同。     

苹果园二斑叶螨药剂防治技术研究

通过田间药剂筛选和防治试验,总结报道了在苹果园应用20％螨死净(Apollo),2.5％天王星(Talstar)、15％扫螨净(Pyridaben)、10％苯丁锡(Fenbutatin oxide)、5％尼索朗(Hexythiazox)和20％灭扫利(Fenpropathrin)防治二斑叶螨的效果及持效期,并且提出了2个关键防治时期。     

飞机草提取物对红脉穗螟的产卵忌避及杀卵活性

为探讨飞机草提取物对红脉穗螟Tirathaba rufivena Walker的防控潜力,采用室内生物测定法,研究了飞机草提取物对红脉穗螟的产卵忌避作用和杀卵活性。结果表明,飞机草乙酸乙酯提取物对红脉穗螟的忌避效果最好,选择性和非选择性忌避率分别为41.85%和46.84%;不同提取物处理红脉穗螟的卵后,均造成卵孵化率降低和初孵幼虫的死亡,其中乙酸乙酯提取物对红脉穗螟卵的影响最大,孵化率和1龄幼虫死亡率分别达到65.89%和40.37%。对飞机草乙酸乙酯提取物进行分级萃取测试各萃取物的活性发现,正己烷萃取物对红脉穗螟的产卵忌避作用和杀卵活性最强。田间试验表明,采用正己烷萃取物稀释50倍和100倍浓度进行田间喷雾,药后15 d对红脉穗螟的种群控制率可达到50%以上。     

二斑叶螨为害对草莓叶片H2O2、MDA含量以及部分防御酶活性的影响

本文旨在探究二斑叶螨Tetranychus urticae为害对草莓Fragaria×ananassa Duch.叶片内过氧化氢（H2O2）、丙二醛（MDA）含量以及部分防御酶活性的影响。在草莓苗上接种不同数量（5~25头）的二斑叶螨,分别在接种后的24 h、48 h和72 h取样,分析草莓叶片内H2O2、MDA的含量以及部分防御酶的活性。结果显示,二斑叶螨为害的草莓叶片内H2O2和MDA的含量以及超氧化物歧化酶（SOD）的活性随着时间的延长而呈现先升后降的趋势,在二斑叶螨持续为害草莓叶片24 h、48 h和72 h时,受损草莓叶片中H2O2的含量均显著高于对照（P<0.05）,不同密度二斑叶螨为害的草莓叶片中H2O2的含量均显著高于对照（P<0.05）,但与取食时间关系不大。当为害时间达到48 h时,MDA的含量和SOD的活性均达到最高峰,此时它们均与二斑叶螨的密度密切相关。当二斑叶螨为25头/叶时,MDA的含量和SOD的活性分别约是对照的3.6倍和10倍。过氧化物酶（POD）和过氧化氢酶（CAT）的活性随时间延长不断升高,均在二斑叶螨为害72 h时达到最高峰。同时,二斑叶螨的为害时间和为害密度之间存在一定的交互作用。以上结果表明草莓叶片主要通过调节其体内H2O2和MDA的含量以及各种防御酶活性的变化,对二斑叶螨的为害产生应激反应。     

Metapopulation dynamics of a persisting predator–prey system in the laboratory: time series analysis

The scarcity of experimental evidence for the persistence of predator–prey systems at the metapopulation level inspired us to develop a simple predator–prey experiment that could be used for testing several theoretical predictions concerning persistence and its causes. The experimental system used consisted of one or several islands with small bean plants, the phytophagous mite Tetranychus urticae and the predatory mite Phytoseiulus persimilis. In the first experiment, one large system was used consisting of 90 small bean plants, prey and predators. The system persisted for only 120 days. Second, a system was used consisting of eight islands with ten plants each where the islands were connected by bridges. Two replicate experiments showed persistence for at least 393 days. The difference between the first and the second experiments suggests that the longer persistence is caused by a limited migration between the eight islands. Despite efforts to start both replicates of the second experiment with similar initial conditions, the dynamics of both replicates varied substantially. In one replicate the prey and predator numbers showed a trend through time, whereas the numbers fluctuated around a fixed value in the other replicate. A time series analysis of the data of the prey and predators showed the presence of periodicity with a lag of 8.5 weeks in one replicate, whereas such cyclic behaviour was not found in the other replicate. The differences between the two replicates suggest that it is difficult to perform experiments where one replicate is perturbed and the other serves as an undisturbed control. We suggest using a longer time series, where a system is disturbed only during the second half of the experiment. The data from the first and second halves can subsequently be used to estimate the effect of the perturbation. The advantages and disadvantages of this method are discussed. This revised version was published online in November 2006 with corrections to the Cover Date.     

Sublethal effects of Beauveria bassiana on life table parameters of two–spotted spider mite,Tetranychus urticae (Acari: Tetranychidae)

Effects of the entomopathogenic fungus Beauveria bassiana were studied on life table parameters of two-spotted spider mite, Tetranychus urticae feeding on bean and cucumber under laboratory conditions. The developmental periods for all immature stages were not affected by fungal infection on each host plant but the duration of larval stage was significantly longer on bean. The female and male longevity, oviposition period and fecundity were significantly lower on fungus-treated mites but were not different between two host plants. Significant reductions were found on the intrinsic rate of increase (r _m ), the net reproductive rate (R ₀), the finite rate of increase (λ), the mean generation time (T _c ) and the population doubling time (D _t ) as a result of mycosis. Only the mean generation time (T _c ) was influenced considering the effect of host plant, which was shorter on cucumber.     

二斑叶螨对六种植物的选择性及生长发育

采用“Y”形嗅觉仪研究二斑叶螨Tetranychus urticae Koch对接骨木(Sambucus williamsii Hance)、苹果(Malus pumila Mill.)、木瓜(Chaenomeles sinensis Koehne)、苦楝(Melia azedarach L.)、火炬树(Rhus typhina Torner)、大叶黄杨(Euonymus japonica Thunb)6种植物的嗅觉选择性差异。结果表明,该螨对苹果叶片的气味表现明显的趋向性,对木瓜叶片的气味表现明显的忌避性,而对其余4种叶片无趋向性或者表现中性。采用海绵水盘法研究在6种植物上的生长发育差异,该螨在接骨木、苹果、苦楝、火炬树上均能正常生长发育至成螨,且具有一定的繁殖力。但在木瓜和大叶黄杨上发育状况较差,繁殖力较差。     

Factors determining the host plant range of the phytophagous mite, Tetranychus urticae (Acari: Tetranychidae): a method for quantifying host plant acceptance

The host plant acceptance of the phytophagous mite Tetranychus urticae was experimentally quantified. Host plant acceptance is described as the proportion of adult females settling on the test plant on which they have been placed. On the other hand, the host plant suitability of T. urticae on different plant species is expressed as the mean number of eggs produced by the females within 5 days (hereafter 'fecundity'). An inbred T. urticae line was tested with regard to host plant acceptance and fecundity on 11 potential host plants. These two variables were positively correlated across host plants; host plant species on which the fecundity was low were also those on which females settled less readily compared to host plants with high fecundity. The characteristics of host plant acceptance of the T. urticae are discussed in light of their potential food resource under natural conditions.     

Different concentrations of Melia azedarach L. (Meliaceae) ethanolic extract on the developmental time and egg laying of Tetranychus urticae Koch

The use of plant-derived chemicals is a new recommended method to control Tetranychus urticae. According to recent studies, Melia azedarach has several compounds which could be effective on insects and mites. The effect of the extract on the fertility and pre-mature period of the mites were investigated at concentrations of 1, 3, 4 and 5?mg mL^?1 of the extract under laboratory conditions. The effect of chemicals extracted from plants was determined using the spraying bioassay method. The leaves being the location of the mites’activity, were sprayed with ethanol extract, then the mites were placed on the discs. In this experiment, the results show that all concentrations were effective, but extract concentrations 4 and 5?mg mL^?1 caused a reduction of more than 50% in the egg laying of the mites and a significant increase in their pre-mature period.     

二斑叶螨发生危害特点及防治对策

本文介绍了二斑叶螨在我国的危害情况和发生规律 ,分析了其发生与危害的特点 ,并提出了有效防治对策     

Phytochemical,acaricidal and biological activity of Dodonaea viscosa L. against the two spotted spider mite Tetranychus urticae Koch

Alcohol extract, saponins and flavones fractionated from Dodonaea viscosa leaves were tested for their acaricidal activity against the adult females of Tetranychus urticae Koch. It was found that crude alcohol extract was more potent than the isolates obtained. At LC₅₀ and LC₉₀ levels, the crude extract ranked the first. All the biotic factors are significantly affected. The fecundity was seriously reduced however, the hatchability of eggs was not affected. Two flavonoids were identified as Querectin 3–0-glucose 7-0-rhamnoside and the other as Querectin 3-0 arabinose 7-0 rhammoside from the ethyl acetate fraction of the alcohol extract.     

6种植物提取物对酪氨酸酶活性的影响

近年来,中草药美容由于疗效显著、毒副作用小而风靡全球。与此同时,中外众多研究者从中国古代治疗皮肤病的方剂中筛选出多种中药,以现代实验手段探讨它们的作用机理,从而更有效地指导美容用品的研制开发,植物药对酪氨酸酶活性的影响便是其中的研究课题之一。已有证据表明,酪氨酸酶在黑色素生成过程中起着极为关键的作用,用药物调节酪氨酸酶的活性,能医治相关的皮肤病[1]。Ｙｕｋｉｍｉｔｓｕ等[2]选用26种在古方中用于皮肤增白的中药进行了酪氨酸酶活性的抑制性试验;雷铁池等[3]用计算机从古今中医治疗色素增加性皮肤病方剂中精选69首进…     

Inhibitory activity of different medicinal extracts from Thuja leaves,ginger roots,Harmal seeds and turmeric rhizomes against Fig leaf mottle-associated virus 1 (FLMaV-1) infecting figs in Mecca region

Fig leaf mottle-associated virus-1 (FLMaV-1) is a closterovirus newly identified in fig trees, in the Mecca region, suffering from mosaic disease symptoms and apparently is compromising the fig plantation in the country. In the present study, we demonstrated the efficiency of two in vivo experiments including pre and post treatments using Thuja leaf, ginger roots, Harmal seeds and turmeric rhizome extracts on symptoms expression of rooted cuttings infected with FLMaV-1- and their impact on virus multiplication. Results showed that individual treatments with ginger roots and turmeric rhizomes in pre-grafting experiments and Thuja extract following Harmal seeds in post grafting experiments were efficient against symptom development. In addition, results showed that the total photosynthesis pigments; total soluble intracellular proteins and total phenol contents were higher in infected treated cuttings compared with healthy ones, thus it was taken as evidence on a mutual interaction between these extracts and virus multiplication.     

火炬树(Rhus typhina)叶挥发性成分及其对两种叶螨选择行为的影响

火炬树为我国于1959年引进的速生绿化观赏性植物,其生长快,长势旺盛,抗病虫害和抗螨能力强,但还未见到其抗螨性和抗螨机理的研究报道.测定了火炬树叶挥发性成分及其对二斑叶螨Tetranychus urticae Koch和山楂叶螨Tetranychus viennensis Zacher选择行为的影响,利用固相微萃取(Solid phase microextraction, SPME)采集、GC-MS测定火炬树叶挥发物,\"Y\"型嗅觉仪分别测定挥发物对两种叶螨选择行为的影响.结果表明,火炬树叶挥发性成分含量由高至低依次为4,6-二特丁基-2-甲基苯酚、4-庚醇、3,7,11-三甲基-2,6,10-二十二三烯-1-醇、丁基化羟基甲苯、α-法呢烯、十八烯、4-甲基-1-丙烯-3-醇、水杨酸甲酯和苯甲酸乙酯等;在两组气味源(火炬树叶与苹果树叶、火炬树叶与空气)中,二斑叶螨对火炬树叶的选择率分别为9.3%和28.9%,山楂叶螨则分别为5.6%和28%,与对照差异显著,但种间差异不显著.因此可以看出,火炬树叶挥发物对叶螨的选择行为具有一定的影响.