Altered host behaviour: manipulation or energy depletion in tapeworm-infected copepods?
Altered host behaviour: manipulation or energy depletion in tapeworm-infected copepods?
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DOI：
10.1017/s0031182002001932
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发表时间：
2002-08-01
期刊：
影响因子：
2.4
通讯作者：
Kurtz, J
中科院分区：
文献类型：
--
作者：
Franz, K;Kurtz, J
寄生虫能够以一种优化它们的生长和传播到下一宿主的方式来影响中间宿主。在感染实足血吸虫(Cestoda)时，白色大环藻的逃逸能力降低，一般活动增加。这便于后续宿主--三刺刺鱼--的捕食。然而，与绦虫对宿主的适应性操纵不同，改变的桡足类行为可能更简单地解释为感染的限制。能量消耗可能会导致肌肉性能下降，并增加寻找食物的活动。此外，感染后宿主组织之间的资源分配可能会发生变化。因此，我们分析了实验感染前后储存脂质和肌肉组织的数量。为了确定肌肉的数量，我们开发了一种新的偏振显微镜技术。不考虑感染，血脂和肌肉是预测桡足类存活的因素。然而，我们没有发现寄生虫感染对肌肉或血脂的影响，也没有迹象表明这些组织之间的资源分配发生了变化。我们的研究表明，受感染的桡足类动物的行为变化是由一种不同于能量耗竭或肌肉和脂肪之间的资源重新分配的机制来调节的。我们更倾向于认为绦虫直接操控桡足类动物的行为。
Parasites are able to influence intermediate hosts in a way that optimizes their growth and transmission to the next host. Macrocyclops albidus (Copepoda) suffer from a reduced escaping ability and an increased level of general activity, when infected with Schistocephalus solidus (Cestoda). This facilitates predation by the subsequent host, the three-spined stickleback. However, instead of adaptive host manipulation by the tapeworm, the altered copepod behaviour might be explained more simply as a constraint of the infection. Energy depletion could lead to decreased muscle performance and increased food searching activity. Furthermore, resource allocation among host tissues might change after infection. We therefore analysed the amount of storage lipids and muscle tissue before and after experimental infection. To determine the amount of muscles, we developed a new polarization-microscopic technique. Irrespective of infection, lipids and muscles were predictors of copepod survival. However, we found no effect of the parasite infection on muscles or lipids, and no indication of a change in resource allocation between these tissues. Our study suggests that behavioural changes in infected copepods are mediated by a mechanism different from energy depletion or a re-allocation of resources between muscles and lipids. We rather propose that the tapeworms directly manipulate copepod behaviour.