Fighting parasites and predators: How to deal with multiple threats?
Fighting parasites and predators: How to deal with multiple threats?
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DOI：
10.1186/1472-6785-12-12
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发表时间：
2012-07-24
期刊：
影响因子：
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通讯作者：
Wolinska, Justyna
中科院分区：
文献类型：
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作者：
Hesse, Olivia;Engelbrecht, Wolfgang;Wolinska, Justyna
背景资料：虽然诱导防御已经被广泛研究，只有很少有人知道寄生虫的存在可能会干扰这些反捕食者的适应。寄生虫和捕食者都是影响生态系统群落结构和物种组成的重要因素。在这里，我们同时将大型蚤暴露在捕食者的暗示下，（释放的蝌蚪虾，Triops，或由鱼）和孢子的酵母寄生虫Metschnikowia sp.，以确定如何生活史和形态诱导防御对这两种截然不同的类型的捕食者受到感染。水蚤失去了产生更多更大后代的能力，这是对Triops捕食的生活史适应。与此相反，寄生虫没有抑制诱导防御对鱼：诱导（导致较小的体长的母亲以及他们的后代）和感染加性作用的测量特性。因此，鱼类诱导的防御可能是成本较低的诱导防御小无脊椎动物的捕食者，如Triops;后者的防御不能再表达时，主机已经投入了战斗的parasita.Conclusions：总之，我们的研究表明，作为特定的诱导防御不同的成本，有些可能会被抑制，如果目标猎物是另外感染。因此，将寄生虫压力加入到捕食者-被捕食者系统中有助于阐明诱导防御的成本。
Background: Although inducible defences have been studied extensively, only little is known about how the presence of parasites might interfere with these anti-predator adaptations. Both parasites and predators are important factors shaping community structure and species composition of ecosystems. Here, we simultaneously exposed Daphnia magna to predator cues (released by the tadpole shrimp, Triops, or by a fish) and spores of the yeast parasite Metschnikowia sp. to determine how life history and morphological inducible defences against these two contrasting types of predators are affected by infection.Results: The parasite suppressed some Triops-induced defences: Daphnia lost the ability to produce a greater number of larger offspring, a life-history adaptation to Triops predation. In contrast, the parasite did not suppress inducible defences against fish: induction (resulting in smaller body length of the mothers as well as of their offspring) and infection acted additively on the measured traits. Thus, fish-induced defences may be less costly than inducible defences against small invertebrate predators like Triops; the latter defences could no longer be expressed when the host had already invested in fighting off the parasite.Conclusions: In summary, our study suggests that as specific inducible defences differ in their costs, some might be suppressed if a target prey is additionally infected. Therefore, adding parasite pressure to predator-prey systems can help to elucidate the costs of inducible defences.