Parasite-induced change in host behavior of a freshwater snail: parasitic manipulation or byproduct of infection?
Parasite-induced change in host behavior of a freshwater snail: parasitic manipulation or byproduct of infection?
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DOI：
10.1093/beheco/10.3.234
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发表时间：
1999-05-01
影响因子：
2.4
通讯作者：
Levri, EP
中科院分区：
文献类型：
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作者：
Levri, EP
由于寄生而引起的宿主行为变化通常被认为是寄生虫的适应。然而，寄生虫的行为效应可能是对寄生的一般性反应，并且仅巧合地有利于寄生虫的传播。出于这个原因，应检验操纵假设的替代假设。以前的工作表明，吸虫寄生虫Microphallus SD影响蜗牛Potamopyrgus antipodarum的行为的方式，可能会增加传播的概率。在这里，我报告的工作进行测试替代操纵假说。在一项实地研究中，将Microphallus对行为的影响与其他两种去势寄生虫群体进行了比较，以确定行为变化是否只是寄生的副产品。此外，在有和没有食物资源的情况下，检查了感染和未感染蜗牛的觅食行为，以确定感染小茎蜗牛的饥饿水平是否可以解释寄生虫引起的行为变化。首先，在白天，在岩石顶部发现感染了微茎线虫的蜗牛的频率低于其他两种寄生虫。这一证据表明，由Microphallus引起的行为变化是特定于Microphallus感染的蜗牛。第二，感染了小茎线虫的蜗牛对食物缺乏的反应与未感染的蜗牛不同。当食物来源从岩石顶部移走时，未感染的蜗牛会撤退到岩石下更安全的位置，而感染了Microphallus的蜗牛则会留在岩石顶部，那里被最终宿主消耗的风险更大。与以前的研究一起，这些结果表明，微阴茎感染导致增强寄生虫传播的行为。
Host behavioral changes due to parasitism are often assumed to be adaptations of the parasite. However behavioral effects of parasites may be a generalized response to parasitism and only coincidentally beneficial for parasite transmission. For this reason, alternatives to the manipulation hypothesis should be tested. Previous work demonstrated that the trematode parasite Microphallus SD influences the behavior of the snail Potamopyrgus antipodarum in a way that may increase the probability of transmission. Here I report work conducted to test alternatives to the manipulation hypothesis. In a field study, the effect of Microphallus on behavior was compared to that of two other castrating parasite groups to determine if the behavioral change is simply a byproduct of parasitism. Also, the foraging behaviors of infected and uninfected snails were examined in the presence and absence of food resources to determine if the hunger level of Microphallus-infected snails could account for the parasite-induced behavioral change. First, Microphallus-infected snails were found on top of rocks during the day less often than the two other parasite groups. This evidence suggests that the behavioral change caused by Microphallus is specific to Microphallus-infected snails. Second, Microphallus-infected snails responded to the lack of food differently from uninfected snails. Uninfected snails retreated to safer positions under rocks when the food source was removed from the top of the rocks, while Microphallus-infected snails remained on top of the rocks where the risk of consumption by the final host is greater. Taken together with previous studies, these results suggest that infection by Microphallus results in behavior that enhances parasite transmission.