An acanthocephalan parasite boosts the escape performance of its intermediate host facing non-host predators
An acanthocephalan parasite boosts the escape performance of its intermediate host facing non-host predators
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棘头动物寄生虫提高其中间宿主面对非宿主捕食者的逃逸性能
DOI：
10.1017/s0031182008004447
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发表时间：
2008
期刊：
影响因子：
2.4
通讯作者：
J. Beisel
中科院分区：
文献类型：
--
作者：
V. Médoc;J. Beisel
摘要 在寄生对宿主条件的潜在影响中，“宿主能力增强”假说是一种违反直觉的模式，可能在复杂生命周期的寄生虫中被预测到。在营养性传播的情况下，寄生虫提高了其中间宿主面对非宿主捕食者的性能，从而提高了其传播到适当的最终宿主的可能性。在本研究中，我们研究了棘头动物多形体感染对其中间宿主甲壳类Gammarus roeseli的运动/逃逸性能的影响。这种寄生虫改变了中间宿主的行为，使其更容易受到鸟类最终宿主的捕食。我们使用压力处理评估了伽马的游泳速度以及它们在捕食压力下的逃生能力。尽管 P. minutus 在其中间宿主的腹部包囊，但受感染的片足类动物的游泳速度明显高于未受感染的片足类动物（增加高达 35%）。此外，当与非宿主甲壳类捕食者 Dikerogammarus villosus 相互作用时，观察到寄生动物的最高逃逸速度和无脊椎动物覆盖的最大距离。在被操纵的无脊椎动物中观察到的行为改变支持了“宿主能力增强”的假设，该假设迄今为止尚未经过实验测试。讨论了提高受感染中间宿主逃避非宿主物种潜在捕食企图的能力的策略。
SUMMARY Among the potential effects of parasitism on host condition, the ‘increased host abilities’ hypothesis is a counterintuitive pattern which might be predicted in complex-life-cycle parasites. In the case of trophic transmission, a parasite increasing its intermediate host's performance facing non-host predators improves its probability of transmission to an adequate, definitive host. In the present study, we investigated the cost of infection with the acanthocephalan Polymorphus minutus on the locomotor/escape performance of its intermediate host, the crustacean Gammarus roeseli. This parasite alters the behaviour of its intermediate host making it more vulnerable to predation by avian definitive hosts. We assessed the swimming speeds of gammarids using a stressful treatment and their escape abilities under predation pressure. Despite the encystment of P. minutus in the abdomen of its intermediate host, infected amphipods had significantly higher swimming speeds than uninfected ones (increases of up to 35%). Furthermore, when interacting with the non-host crustacean predator Dikerogammarus villosus, the highest escape speeds and greatest distances covered by invertebrates were observed for parasitized animals. The altered behaviour observed among the manipulated invertebrates supported the ‘increased host abilities’ hypothesis, which has until now remained untested experimentally. The tactic of increasing the ability of infected intermediate hosts to evade potential predation attempts by non-host species is discussed.