捕食植物的捕食结构

据统计,全世界能捕食动物的捕食植物约有五百多种.广泛分布在世界各地,自然界中存在的这种特殊类型的捕食方式,是由于它们所处的特殊自然环境所决定的。它们往往生存在氮素和其他矿质养料较匮乏、自然条件并不十分优越的环境中,单纯地靠体内叶绿体进行光合作用,只能维持短暂的生活,必须靠捕食动物来补充体内的营养物质,维持自身的生存,在长期的自然选择中,这种适应不断被巩固和加强,其形态结构变得更有利于巧妙和有效地捕捉动物,这类捕食结构的特化,主要表现在以下几个方面:     

有扩散的捕食与被捕食动力系统

本文证明带有扩散的捕食与被捕食Ｌｏｔｋａ－Ｌｏｌｔｅｒｒａ模型的如下性质：该模型的一切正解是持续生存的;当扩散率较小时该系统的正平平衡点是稳定的;当扩散率增大且位于某一区间内变化时该系统的正平衡点是不稳定的,而且分支出唯一的小振幅空间周期解;当扩散率继续增大时该系统的正平衡点又变为稳定的。     

Lotka-Volterra捕食-被捕食系统的脉冲控制

本文利用脉冲微分方程的比较原理,通过状态和输出反馈研究了Lotka-Volterra捕食－被捕食系统的脉冲控制问题。得到了所研究模型的非负平衡点渐近稳定的充分条件。对于所实施的使系统渐近稳定的脉冲控制,给出了脉冲控制时间间隔的上界估计值。     

牛蛙捕食麻雀

牛蛙（bullfrog，Rana catesbeiana）原产于北美洲洛基山脉以东地区，体大而粗壮，体长150～160mm．最大者可达200mm。生活于暖温带的水域中，主要以水生昆虫、无脊椎动物、小鱼、小型蛙类及蝌蚪等为食，也有捕食蛇、幼鳄、小型兽类以及雏鸭和雀类的报道。已知文献报道的牛蛙捕食鸟类，多是基于解剖胃的内容物而得知的。由于其食用价值很高，近百年来已被广泛引入到世界各地人工饲养，甚至野放到自然水域内生存。[第一段]     

具有捕食正效应的捕食-食饵系统

在经典的捕食食饵系统中考虑到由于捕食效应对食饵种群带来的正向调节作用后,提出了具有捕食正效应的捕食-食饵系统.通过对模型的动力学行为的分析,从理论上说明了正向调节作用对系统的影响,并就第一象限内平衡点存在时的相图解释了捕食正效应的作用.结果表明:(1)捕食系统中适当的正向调节作用会增加系统的稳定性;(2)当捕食正效应达到一定的程度后系统拥有一个不稳定的极限环;(3)当捕食正效应过大时会使系统的稳定性发生变化,使捕食者种群与食饵种群同时趋向无穷,出现了调节放纵现象.这些结果在保护生物学中具有重要的意义.     

捕食线虫真菌

捕食线虫真菌是一类通过捕食器官捕食线虫的生物,在自然界是影响线虫数量的主要因子。对捕食线虫真菌的捕食器官、捕食机制、捕食线虫真菌的形态及其在植物线虫的生物防治进行了简要论述。     

一类具连续时滞的捕食-被捕食生态系统

本文讨论了一类具有强连续时滞的捕食-被捕食模型,分析了各非负平衡点的稳定性,利用区域连续收缩方法,得出非负平衡点全局稳定的充分条件,给出正平衡点全局稳定的充分条件,并给出系统出现Hopf的分支值．     

具时滞的捕食与被捕食系统的动力分析

研究了具有时滞的捕食与被捕食系统,分析了系统的正不变集、边界平衡点性质、全局渐近稳定性和持久生存性.当时滞(?)很小时,系统在正平衡点是局部渐近稳定的,当(?)从0增到(?)_0时,系统在正平衡点附近产生Hopf分支.     

猫科动物的捕食策略

<正>外表美丽的猫科动物无一例外的都是肉食性的掠食者,它们处在食物链的顶端,属于一级消费者,控制着食草动物和其他动物的数量,从而维系着大自然中的生态平衡。百万年以来,现存的猫科动物自身均进化出了一套精良的"武器设备",它们大都有完美的保护色、出色的身体柔韧性与惊人的爆发力,加上     

水蛭捕食两栖类卵

许多卵生动物具有对付食卵者的精巧策略以降低死亡率,因为早期发育阶段的捕食压力能显著影响具复杂生活史动物的生存。两栖动物卵被水蛭等很多物种所捕食。我们查阅了水蛭捕食两栖类卵的文献,发现27篇论文。在所报道的水蛭捕食两栖类卵的例子中,无尾类(3.6%,n=591)明显多于有尾类(1.6%,n=255)。此外,我们第一次记录到水蛭捕食四趾螈(Salamandrina perspicillata)卵,这也是西欧有尾类的第一例报道。我们没有发现两个两栖动物类群间存在差异。然而,当我们分别分析来自北美、欧洲和亚洲三个地区的数据时,发现北美的有尾类和无尾类间存在显著差异。水蛭可捕食各生活史阶段的两栖动物,因此,水蛭应归为一些两栖类的天敌。     

Mutual interference between predatory anthocorids

• 1 The way in which the predator Anthocoris confusus reacts to the presence of other individuals of the same species is described.
• 2 Mutual interference between adult A.confusus leads to a density-dependent decrease in egg production, due mainly to an increased tendency to migrate from areas of high predator density.
• 3 Even when ten first instar predators were present in a 2 cm diameter cage they did not interfere with each other unless the amount of food available was inadequate for survival.
• 4 Mutual interference between A.confusus adults promotes stability in populations of the predator and will lead to even exploitation of an unevenly distributed food source.

     

The predatory behavior of Pheidole megacephala

We studied the foraging and predatory behaviors of the invasive African myrmicine ant, Pheidole megacephala (F.) in its native range. Workers can singly capture a wide range of insects, including relatively large prey items. For still larger prey, they recruit at short range those nestmates situated within reach of an alarm pheromone and together spread-eagle the insect. These behaviors are complimented by a long-range recruitment (of nestmates remaining in the nest) based on prey size. P. megacephala scouts also use long-range recruitment when they detect the landmarks of termites and competing ant species, thus permitting them to avoid confronting these termites and ants solitarily.     

Egg dumping by predatory insects

Synovigenic insects resorb oocytes when food is scarce and mature oocytes when food is plentiful. These two antagonistic processes allow an optimal allocation of resources to reproduction and somatic functions. Unlike hymenopteran parasitoids, ladybirds cannot resorb mature oocytes present in the oviducts. Is the energy contained in these oocytes lost or is there a mechanism for recovering it when needed? Females of two species of ladybird beetles Adalia bipunctata (L.) and Adalia decempunctata (L.) that are starved for >24 h lay single infertile eggs, which they immediately eat, and these eggs comprise the mature oocytes in the oviducts at the onset of starvation. This behaviour has some similarities to egg dumping reported in herbivorous insects and is part, in ladybird beetles, of a process to retrieve energy invested in reproduction. Such behaviour may exist in other predatory synovigenic insects species that do not invest in maternal care.     

Hibernation of predatory arthropods in semi-natural habitats

Non-crop habitats provide important resources for natural enemies. Many natural enemies hibernate in non-crop habitats, from which they may colonise arable fields in the spring. Spring colonisation ensures annual repopulation of the crop with natural enemies, allowing them to keep pace with the development of pest populations. The availability of non-crop habitats can, therefore, be crucial to successful conservation biological control. We quantified the density of overwintering natural enemies near organic Brussels sprout crops in five different non-crop habitats (short grassy field margin, herbaceous field margin, herbaceous field margin under a tree line, ditch and forest). Soil and litter samples of non-crop habitats were taken at two sites. One site was located in an open agricultural landscape, the other in a landscape dominated by mixed forest. Insects belonging to Staphylinidae, Araneae, Carabidae, Coccinellidae and Dermaptera were the most abundant. Mean densities of predatory arthropods were higher in the open agricultural landscape (290 predators m⁻²) than in the forested landscape (137 predators m⁻²). Herbaceous habitat types supported the highest densities of overwintering predators (up to 400 predators m⁻²), whereas densities in the forest were lowest (10 predators m⁻²). These results indicate that herbaceous non-crop habitats are important refugia for predators and may play a vital role in conservation biological control. Handling Editor: Arne Janssen.     

捕食性天敌昆虫控害作用定量评价方法

天敌昆虫田间捕食作用与能力的研究,通常采用田间种群数量调查与分析的方法或笼罩试验来评价其控制作用,但往往与实际情况不符,尤其是对可捕食多种猎物的非专食性天敌,很难说明其在田间对某一特定猎物的控制作用究竟有多大,而分子生物学技术为捕食者-猎物关系评价研究提供了新途径。本文系统介绍了基于种特异性SS-PCR标记技术和TaqMan-MGB实时荧光定量PCR技术的捕食性天敌控害作用定量评价方法及其优缺点,旨在为害虫天敌的种类筛选及其保护利用提供技术指导。     

In search of artificial domatia for predatory mites

Banker plants can enhance biological pest control by providing both floral resources and appropriate oviposition sites, e.g. through acarodomatia, to predator species. The use of materials mimicking domatia i.e. artificial domatia may be an economically favourable alternative to the use of banker plants bearing domatia. The aim of the present study was to identify materials that are able to host eggs of the Neoseiulus californicus predatory mite but not those of the Tetranychus urticae pest mite. In a laboratory experiment, the oviposition of predatory and phytophagous mites were compared in Petri dishes containing leaves. The different modalities compared were (i) natural domatia of Viburnum tinus or (ii) one of twelve potential artificial domatia materials. The overall oviposition response of predatory mites to all artificial domatia was similar to that of the natural domatia. The oviposition of the Tetranychus urticae pest mite did not increase in response to the artificial domatia. Five artificial domatia hosted as many eggs of the predatory mite as observed in the natural domatia. The effect of the physical properties of artificial domatia was also tested and N. californicus was found to favour the artificial domatia that had high heat retention capacities for oviposition. Three of these artificial domatia were tested on rose plants in a greenhouse experiment; none of which enhanced the biological control on the plants under these conditions. The present study highlights the difficulty in identifying and using suitable artificial domatia as substitutes to banker plants in biological pest control efforts.