麦蚜虫霉流行病的初始侵染源及传播途径观察

在河南省原阳县麦区于2002年4~5月期间自空中诱捕到迁飞性有翅麦蚜共1092头, 其中麦长管蚜(Sitobion avenae)415头, 禾谷缢管蚜(Rhopalosiphum padi)642头, 麦无网长管蚜(Metopolophium dirhodum)22头, 麦二叉蚜(Schizaphis graminum)13头. 每日诱获的有翅蚜带回室内在试管麦苗上单头饲养7 d, 共发病死亡341头(麦长管蚜224头, 禾谷缢管蚜106头, 麦二叉蚜3头, 麦无网长管蚜8头), 全部在饲养的前5天死亡, 其中前3天的死亡占78.9%, 有翅蚜的总带菌率为31.2%. 病死有翅蚜经逐头镜检确认病因, 全系虫霉感染所致, 其中新蚜虫疠霉(Pandora neoaphidis)占84.6%, 普朗肯虫霉(Entomophthora planchoniana)占5.5%, 暗孢耳霉(Conidiobolus obscurus)占9.9%, 另有4例为新蚜虫疠霉和暗孢耳霉的复合感染. 基于迁飞性有翅麦蚜高比例带菌和田间麦蚜虫霉流行病的调查资料, 可以认为麦蚜的虫霉流行病可能主要借有翅蚜的迁飞定殖而异地传播, 并讨论了这种传播方式对蚜虫流行病研究与利用的启示.     

烟蚜茧蜂随寄主有翅桃蚜迁飞而被携带扩散的模拟实验

蚜虫寄生蜂的广泛分布可能与有翅蚜的迁飞有关。为了证明这一假说, 本研究利用微小昆虫飞行磨系统, 分数十批(≤16头/批)对被烟蚜茧蜂Aphidius gifuensis Ashmead单头寄生后的有翅桃蚜Myzus persicae (Sulzer)进行模拟飞行并系统观察了飞行后有翅桃蚜的单头定殖情况。对实验观察数据按飞行时间和飞行距离进行归类, 采用单因素方差分析方法分析飞行时间和飞行距离对有翅桃蚜定殖后的存活和生殖力、烟蚜茧蜂发育等变量的影响; 采用多项式回归分析对所有变量和归类的数据进行统计和分析。结果表明: 成功飞行并定殖的有翅桃蚜有378头, 其中239头有翅桃蚜定殖后形成僵蚜。形成僵蚜的有翅桃蚜在飞行实验时平均飞行时间和飞行距离分别为2.63 h和2.16 km, 定殖后平均存活了6.11 d, 定殖第6天和第14天平均产若蚜累计数量分别为8.5头和162头。形成僵蚜和未形成僵蚜的有翅蚜的模拟飞行数据和定殖观察数据无显著差异。形成僵蚜的239头有翅桃蚜中, 最终成功育出烟蚜茧蜂205头, 僵蚜出蜂率为85.8%。雌雄性比为1∶5.2。结论认为, 专性寄生蚜虫的烟蚜茧蜂可以利用有翅蚜的迁飞而被携带扩散传播, 有翅蚜迁飞在蚜虫寄生蜂扩散中具有重要作用。     

云南高原地区马铃薯田有翅蚜种类及迁飞动态

2008-2010年,在云南省马铃薯种薯基地会泽县和香格里拉县采用黄皿诱集法开展马铃薯田蚜虫种类及其有翅蚜迁飞消长特征研究,结果表明:(1)两地共采集到18种有翅蚜,分属于3科10属。其中,滇东北会泽县有3科10属18种,滇西北香格里拉县有2科5属6种。桃蚜Myzus persicae Sulzer、棉蚜Aphis gossypii Glover和甘蓝蚜Brevicoryne brassicae Linnaeus是两地的优势种,占总诱集量的60.9%-97.8%。(2)在会泽县,薯田优势种蚜虫迁飞全年有2个发生高峰期,首个高峰期为5月上旬-6月中旬,诱集量1.6头/皿-4.7头/皿,第2次迁飞峰期为6月下旬-8月中旬,诱集量0.7头/皿-7.3头/皿,桃蚜的迁飞要稍早于甘蓝蚜和棉蚜。(3)在香格里拉县,薯田有翅蚜迁飞峰期晚于会泽县,3种蚜虫每年呈现2次迁飞峰期。首次迁飞峰期为6月底至8月初,诱集量0.2头/皿-6.0头/皿,第2次迁飞峰期为7月中至8月底,诱集量0.3头/皿-8.3头/皿,棉蚜迁飞早于桃蚜和甘蓝蚜。     

黄板诱蚜试验初报

试验早已证明,蚜虫超飞时是向着天空的短波光飞翔的;但在降落时,却受植物表面所反射的黄色等长波光吸引。黄板诱蚜,就是利用有翅蚜降落时对黄色趋性的原理,来防治蚜虫的。实践证明,大面积开展黄板诱蚜,是消灭蚜虫的有效办法之一。 1975年4月,我们在利用黄板测报棉蚜由越冬寄主迁向棉苗时,看到黄颜色对有翅蚜的诱集力很强。在第一次迁飞高峰期4月26—30日,五天中,一块黄板两面共诱获有翅蚜202头。因此,5月中旬刈麦后,在孔东公社六大队1,037亩棉地上普遍开展黄板诱蚜。仅在棉蚜第二次迁飞高峰期5月23—29日七天中,每块黄板共诱获有翅蚜337头。在6月份,棉田中棉蚜     

蚜虫迁飞的研究进展

蚜虫的迁飞能造成危害扩展、病毒病传播和防碍人们的正常生活。蚜虫迁飞有其生理生态基础。寄主营养、蚜群拥挤度、天敌以及气候条件是刺激有翅蚜产生的主因素。蚜虫迁飞与卵巢发育存在明显的共轭关系。蚜虫迁飞多发生在晴朗的白天 ,并且温度、光照和风是影响迁飞行为的主导因子。蚜虫可上升到逆温层并随气流迁飞到上百公里以外的地方。目前 ,昆虫雷达观察、天气学分析和分子生物学方法已应用于蚜虫迁学的研究中 ,文章对蚜虫迁飞的生理生态基础、迁飞行为、影响迁飞的生态因子以及研究方法进行了综述 ,以期为蚜虫这类小型昆虫的迁飞研究提供指导     

棉蚜迁飞型和居留型及其杂交后代飞行特性的比较研究

为了明确棉蚜种群飞行能力发生分化的遗传基础,本文对春季木槿上有翅棉蚜中的起飞个体和不起飞个体分别进行连续4代次和2代次的起飞特性选择。结果表明,棉蚜的起飞比率和起飞角度特性表现出了明显的选择响应,并筛选出了棉蚜的迁飞型(M)和居留型(S)。通过对棉蚜性蚜的诱导,摸索出了棉蚜性蚜交配及卵孵化的条件。对迁飞型(M)、居留型(S)、迁飞型和居留型的正反交后代（M♀×S♂,S♀×M♂）、夏季木槿上的滞留蚜（H）等5类棉蚜的起飞特性进行了比较研究。结果表明,迁飞型和居留型的正反交后代的起飞比率显著高于居留型,且稍高于迁飞型。迁飞型雌蚜与居留型雄蚜的杂交后代的起飞角度显著高于居留型和夏季木槿上的滞留蚜。居留型产生有翅蚜的比率低于迁飞型及其与居留型的正反交后代。棉蚜的起飞角度、起飞比率及有翅蚜产生能力表现出了较强的遗传效应。平均起飞时间虽然表现出迁飞型雌蚜与居留型雄蚜的杂交后代显著短于迁飞型雄蚜与居留型雌蚜的杂交后代及夏季木槿上的滞留蚜,但与迁飞型和居留型之间却无显著差异,表现出棉蚜起飞时间特性的遗传效应不明显。     

麦长管蚜有翅成蚜母代饥饿对其后代发育和繁殖的影响

【目的】分析麦长管蚜Sitobion avenae有翅成蚜饥饿胁迫下的母性效应,为迁飞性有翅蚜在新栖息地的成功定殖和种群延续研究提供依据。【方法】以正常取食个体为对照,观察麦长管蚜有翅成蚜饥饿24, 48, 72, 96, 120和144 h后的存活率以及恢复取食后24 h之内初产后代数、个体大小和随后生长发育与繁殖情况,评价母代饥饿胁迫对后代的潜在影响。【结果】在同一处理时间,饥饿组麦长管蚜有翅成蚜的存活率均低于正常取食对照,且在饥饿胁迫期间很少产仔,但恢复取食后24 h之内初产后代数高于正常取食对照。随母代饥饿时间延长,恢复取食后24 h之内初产后代的个体大小随饥饿时间延长而减小,当饥饿时间≥96 h,有翅成蚜初产后代的个体大小显著小于同一时间取食个体的初产后代。将恢复取食后24 h之内的初产后代在正常取食条件下单头饲养,发现随母代饥饿胁迫时间延长,其后代的若虫历期显著延长,其中母代经120 h和144 h饥饿胁迫后,相比于同一时间取食有翅成蚜的后代若虫历期,分别延长了15.1%和15.8%,差异达显著水平。但母代饥饿时间并不影响恢复取食后24 h之内所产后代的若虫存活率、无翅蚜率以及成虫寿命和产仔量。【结论】麦长管蚜有翅成蚜母代饥饿可使其存活率降低,但恢复取食后24 h之内初产后代数高于同一时间正常取食个体;母代饥饿时间延长,恢复取食后24 h之内初产后代的个体大小减小,若虫历期延长,而对恢复取食后24 h之内所产后代的若虫存活率、无翅蚜率以及成虫寿命和产仔量并无影响,这种适应性反应可能是迁飞性有翅蚜在新栖息地成功定殖的重要因素之一。     

豆蚜有翅蚜产生的原因

本文研究拥挤、寄土质量、温度和蚜型等因子对大豆蚜(Ahis glyeines)有翅蚜产生的影响。结果表明：1.大豆蚜无翅胎生成好个体间的拥挤是有翅蚜产生的主要原因。在低密度下拥挤反应随密度增大而增强,但过度拥挤会导致反应的降低。无翅若好间的拥挤不能导致其本身发育为有翅胎生蚜。 2.寄主质量能改变无翅胎生成蚜对拥挤的反应。每笼2头经成熟叶片处理的无翅胎生成蚜后代中有姻蚜的比例高于幼嫩叶片和对照(无叶片)处理,且饥饿不能促进有翅蚜的产生。3.温度能影响有翅蚜的产生。较高的温度(30℃和25℃)较21℃对有翅胎生蚌的产生有较强的抑制作用。4.不同母蚜型产生有翊蚜的能力不同。有翅胎生蚜间的拥挤也能使其在后代中产生少量的有翊蚜,但对拥挤的敏感程度低于无翅胎生蚜。     

浅谈蚜虫对其高密度种群的适应

蚜虫是一种多态性昆虫,其繁殖量的多少和蚜型的分化在很大程度上受种群密度的影响,当种群的数量达到环境容纳量时,不同种类的蚜虫便会采取各种措施以降低繁殖力,使整个种群的数量基本保持在平衡密度的水平上。这些措施包括分化出缺乏繁殖力的兵蚜,产生有翅蚜迁飞到其他的寄主上以及降低产仔量和缩短寿命等。采取这些策略能够使整个种群避免食物不充足而持续的繁衍下去．是蚜虫对环境适应的一种表现。     

菜蚜迁飞期短期预测的研究Ⅰ

在1961年及1963—65年,我们在北京和天津对十字花科蔬菜上的两种蚜虫——桃蚜Myzus persicae(Sulzer)和菜缢管蚜Hyadaphis erysimi pseudobrassicae(Davis)——分别在留种白菜、留种萝卜、甘蓝、苤蓝、小白菜、小油菜、秋白菜,以及春天的风障菠菜上进行了系统的蚜群分析。研究表明,在蚜群中出现有翅若蚜前,繁殖力有下降趋势;因而若蚜与成蚜数量的比值亦逐渐下降。降到一定的比值,蚜群中即将出现有翅若蚜。因此,可以通过系统调查,用统计蚜群中若蚜与成蚜的数量比,来作蚜虫迁飞期的短期预测。 数量分析表明:桃蚜出现有翅若蚜前4—6天,其若蚜与成蚜的数量比为2.17—2.91(95%置信限)或2.03—3.05(99%置信限)。菜缢管蚜有翅若蚜出现前5—6天其比值为8.56—9.76(95%置信限)或8.29—10.03(99%置信限)。     

Characteristics of the membranes of the pellicle of the ciliatePseudomicrothorax dubius

Summary The membranes of the pellicle of the ciliatePseudomicrothorax dubius are investigated using thin section electron microscopy and freeze-fracture replicas. The plasma membrane is covered by a surface coat and is connected to the outer alveolar membrane by short, sometimes branched, bridges. The inner alveolar membrane is coated on both sides. The epiplasm lies in intimate contact with the cytoplasmic surface of this membrane, and there is a corresponding deposit on the other surface. This deposit is regularly striated.The epiplasmic layer and the alveoli are interrupted at sites of cytotic activity,e.g., the attachment sites of trichocysts, the cytoproct, and the parasomal sacs. The striated deposit ends where the epiplasm ends, indicating a direct relationship between these two epimembranous layers.There is a deposit along the sides of the first part of the tip of the trichocysts, and in this region the trichocyst membrane is free of intramembranous particles.The membrane of the parasomal sacs has a coat on both surfaces. That on the extraplasmic surface is similar to the surface coat of the plasma membrane. The origin of the cytoplasmic coat is unknown. The cytotic activity of these sacs is indicated by their highly irregular profiles.     

The early development of the tail and the transformation of the shape of the nucleus of the spermatid of the domestic fowl,Gallus gallus

Summary The differentiation of the spermatid, especially in reference to the formation of the flagellum, and transformation of the shape of the nucleus was investigated in the domestic fowl.In the early stage of the spermatid, a prominent Golgi apparatus appears around the centrioles. The Golgi vesicles then surround the axial-filament complex which develops from the distal centriole. These vesicles fuse to form continuous membrane at the earliest stage of flagellar formation, and in the succeeding stage Golgi lamellae are attached to the plasma membrane of the developing flagellum. From these observations, it is assumed that Golgi apparatus may be a source of the membrane system of the flagellum.The microtubules distributed around the nucleus form the circular manchette. The anterior region of the nucleus with the manchette is cylindrical in shape and the posterior region without it remains irregular in shape. When the circular manchette has been completed, the whole nucleus acquires a slender cylindrical shape. The circular manchette then changes into the longitudinal manchette. The nuclei of spermatids without a longitudinal manchette are abnormal in shape. In view of these observations it is assumed that the nuclear shaping of the spermatid may be accomplished by circular manchette and the maintenance of shape of the elongated nucleus by longitudinal manchette.The authors wish to thank Mr. Takayuki Mori for his helpful suggestions and technical advices     

Characterization of the composition of the aqueous humor and the vitreous body of the eye of the frog Rana temporaria L

This study aimed to analyze the aqueous humor (AH) and the vitreous body (VB) of the eye of the adult frog Rana temporaria L. as a representative species of amphibians, which lead a semi-terrestrial life. The presence of collagen, albumin, uric acid and electron donors was shown in both media; however, there are slight differences in their concentrations. To determine collagen, a spectral-fluorescent probe, cyanine dye, was used. The presence of collagen in AH of the frog was found at the first time. The total content of electron donors (ascorbic and uric acids, tryptophan, and tyrosine) in VB and HA was roughly estimated at ~ 1.5 × 10^− 4 mol/L. Both VB and AH absorb light in similar UV regions. The total protein and albumin contents in AH were found to be somewhat higher than those in VB. The uric acid content was at an equally low level in both intraocular media. It is supposed that the similarity of VB and AH compositions shown in this work is due to some exchange between VB and AH contents in the course of accommodation. The role of intraocular fluids in physiological functions of the eye and in protecting the retina against UV light is discussed.     

Observations on the permeability of the choriocapillaris of the eye

Summary The choriocapillaris is a fenestrated capillary bed located posterior to the retinal pigment epithelium. It serves as the main source of supply to the photoreceptors, retinal pigment epithelium, and other cells of the outer retina. The permeability of these capillaries to intravenously injected ferritin (MW — approx. 480,000; mol. diam. 11 nm) was examined in the mouse, rabbit, and guinea pig, each of which is characterized by a different type of retinal vascularization. In all three species, the bulk of the ferritin remained in the capillary lumina, where it appeared to be blocked at the level of the diaphragmed fenestrae. Some ferritin was present in endothelial cell vacuoles. The results confirm previous work on the rat choriocapillaris and indicate that the barrier function of the choriocapillary endothelium is present even among species in which the retinal circulation differs significantly.Supported by NIH grant EY03418