Department of Zoology, School of Natural Sciences, National University of Ireland, University Rd, Galway, Ireland.
J Insect Physiol. 2012 Jun;58(6):874-80. doi: 10.1016/j.jinsphys.2012.03.014. Epub 2012 Apr 7.
Many animal phyla contain clades in which most or all species are venom-injecting predators. An example, in the arthropods, is the class Chilopoda, containing the approximately 3500 species of centipedes. Very little ecological or behavioural work yielding quantitative data has been conducted on centipede predation. Here, we describe a study of this kind. Our experiments employed one centipede species - a large tropical one, Scolopendra subspinipes mutilans - and two species of prey - a cricket, Gryllus assimilis, and a locust, Schistocerca gregaria. We conducted two experiments. The first was aimed at investigating the extent to which the centipedes attacked prey in particular tagmata as opposed to at random over the whole body surface. The results showed that the centipedes were highly selective, preferring to attack the head or thorax rather than the abdomen; indeed, they often reoriented the prey in order to achieve this. A possible explanation of this behaviour is to maximize the speed with which the neurotoxins in the venom reach either the brain or the thoracic ganglia that control limb movement. The second experiment was aimed at investigating the effect of venom-extraction on the attack rate, and specifically at testing if the magnitude of any such effect differed between the two types of prey, which differ considerably in size. The results showed a major effect of venom extraction in relation to both types of prey, but with the time taken to return to a 'normal' attack rate being longer in the case of the larger prey-type, namely the locust. We discuss these results in relation to the 'venom optimization hypothesis' and, more generally, to the principle of minimizing the production/use of venom, which is an energetically expensive resource.
许多动物门包含大多数或所有物种都是注射毒液的捕食者的进化枝。节肢动物门中的一个例子是多足纲，其中包含大约 3500 种蜈蚣。对蜈蚣捕食行为进行了很少的生态或行为学研究，也没有产生定量数据。在这里，我们描述了这样的一项研究。我们的实验使用了一种蜈蚣物种——一种大型热带蜈蚣，Scolopendra subspinipes mutilans——以及两种猎物——一种蟋蟀，Gryllus assimilis，和一种蝗虫，Schistocerca gregaria。我们进行了两项实验。第一项实验旨在调查蜈蚣在特定体节攻击猎物的程度，而不是随机攻击整个身体表面。结果表明，蜈蚣具有高度的选择性，更喜欢攻击头部或胸部，而不是腹部；事实上，它们经常重新定向猎物，以便达到这个目的。这种行为的一种可能解释是最大限度地提高毒液中的神经毒素到达大脑或控制肢体运动的胸部神经节的速度。第二项实验旨在调查毒液提取对攻击率的影响，特别是测试这种影响的大小是否在两种类型的猎物之间有所不同，这两种猎物在大小上有很大的差异。结果表明，毒液提取对两种猎物都有很大的影响，但对于较大的猎物型，即蝗虫，恢复到“正常”攻击率所需的时间更长。我们将这些结果与“毒液优化假说”以及更普遍的最小化毒液产生/使用原则进行了讨论，毒液是一种能量消耗大的资源。
