The effects of parasite age and intensity on variability in acanthocephalan-induced behavioural manipulation
The effects of parasite age and intensity on variability in acanthocephalan-induced behavioural manipulation
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DOI：
10.1016/j.ijpara.2008.01.003
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发表时间：
2008-08-01
影响因子：
4
通讯作者：
Rigaud, Thierry
中科院分区：
文献类型：
--
作者：
Franceschi, Nathalie;Bauer, Alexandre;Rigaud, Thierry
许多具有复杂生命周期的寄生虫能够操纵其中间宿主的行为，从而增加其向终末宿主的营养传递。Pomphorhynchus laeuis是一种棘头类寄生虫，已知它可以逆转其端足类中间宿主钩虾的趋光行为，从而增加鱼类宿主的捕食。然而，自然感染的gammarids表现出的行为操纵水平是非常可变的，一些人被强烈操纵，而另一些人几乎不受感染的影响。为了调查寄生虫的年龄和寄生虫强度作为这种变化的潜在来源，我们进行了控制实验感染gammrids使用寄生虫从两个不同的人群。我们首先确定，寄生虫的强度与暴露剂量增加，但没有发现感染和宿主死亡率之间的关系。重复的措施证实，寄生虫改变主机的行为，只有当它达到囊棘虫阶段，这是感染的最终主机。他们还首次揭示了，我们相信，越老的囊棘鱼，它就越能操纵它的宿主。因此，寄生虫的年龄是寄生虫操作变异的主要来源。宿主体内寄生虫的数量也是变异的一个来源。操纵是较高的两个寄生虫感染的主机比在单一感染的，但以上的强度，操纵并没有增加。由于寄生虫的发育时间也不同，根据寄生虫的强度（它是在双重感染的主机比在单感染的，但没有增加更多的多感染的主机），个别寄生虫健身可能取决于开发时间和操作效率之间的妥协。最后，测试的两种寄生虫种群诱导的行为操纵程度略有不同。(C)2008年澳大利亚寄生虫学会由爱思唯尔有限公司出版。保留所有权利。
Numerous parasites with complex life cycles are able to manipulate the behaviour of their intermediate host in a way that increases their trophic transmission to the definitive host. Pomphorhynchus laeuis, an acanthocephalan parasite, is known to reverse the phototactic behaviour of its amphipod intermediate host, Gammarus pulex, leading to an increased predation by fish hosts. However, levels of behavioural manipulation exhibited by naturally-infected gammarids are extremely variable, with some individuals being strongly manipulated whilst others are almost not affected by infection. To investigate parasite age and parasite intensity as potential sources of this variation, we carried out controlled experimental infections on gammarids using parasites from two different populations. We first determined that parasite intensity increased with exposure dose, but found no relationship between infection and host mortality. Repeated measures confirmed that the parasite alters host behaviour only when it reaches the cystacanth stage which is infective for the definitive host. They also revealed, we believe for the first time, that the older the cystacanth, the more it manipulates its host. The age of the parasite is therefore a major source of variation in parasite manipulation. The number of parasites within a host was also a source of variation. Manipulation was higher in hosts infected by two parasites than in singly infected ones, but above this intensity, manipulation did not increase. Since the development time of the parasite was also different according to parasite intensity (it was longer in doubly infected hosts than in singly infected ones, but did not increase more in multi-infected hosts), individual parasite fitness could depend on the compromise between development time and manipulation efficiency. Finally, the two parasite populations tested induced slightly different degrees of behavioural manipulation. (C) 2008 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.