Life cycle abbreviation in the trematode Coitocaecum parvum:: can parasites adjust to variable conditions?
Life cycle abbreviation in the trematode Coitocaecum parvum:: can parasites adjust to variable conditions?
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DOI：
10.1111/j.1420-9101.2006.01277.x
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发表时间：
2007-05-01
影响因子：
2.1
通讯作者：
Poulin, R.
中科院分区：
文献类型：
--
作者：
Lagrue, C.;Poulin, R.
寄生虫复杂的生命周期被认为是从简单的单宿主周期进化而来的，通过引入新的宿主。然而，复杂的发育途径为寄生虫提供了一系列极不可能的传播事件，以完成其生命周期。一些吸虫如Coitocaecum parvum使用兼性生命周期缩写来对抗营养传播到最终宿主的可能性。采用生命周期截短的寄生虫具有在其中间宿主内繁殖的能力，使用子代，而不需要到达最终宿主。通常，在同一种群的寄生虫中观察到缩短的和正常的生命周期。在这里，我们通过实验证明，C。寄生虫可以调节其在端足类中间宿主中的发育，并根据当前的传播机会或个体寄生虫之间宿主内竞争的程度而采用缩短的或正常的生活周期。在其捕食性的最终宿主的线索的存在下，寄生虫是显着不太可能通过progenesis比在没有这样的线索。当寄生虫暴露于来自非宿主捕食者的线索时，获得中间响应。然而，当两个寄生虫共享资源有限的中间宿主时，采用子代的可能性较小。这些结果表明，具有复杂发育途径的寄生虫具有比以前认为的更复杂的传播策略和感知能力。
The complex life cycles of parasites are thought to have evolved from simple one-host cycles by incorporating new hosts. Nevertheless, complex developmental routes present parasites with a sequence of highly unlikely transmission events in order to complete their life cycles. Some trematodes like Coitocaecum parvum use facultative life cycle abbreviation to counter the odds of trophic transmission to the definitive host. Parasites adopting life cycle truncation possess the ability to reproduce within their intermediate host, using progenesis, without the need to reach the definitive host. Usually, both abbreviated and normal life cycles are observed in the same population of parasites. Here, we demonstrate experimentally that C. parvum can modulate its development in its amphipod intermediate host and adopt either the abbreviated or the normal life cycle depending on current transmission opportunities or the degree of intra-host competition among individual parasites. In the presence of cues from its predatory definitive host, the parasite is significantly less likely to adopt progenesis than in the absence of such cues. An intermediate response is obtained when the parasites are exposed to cues from non-host predators. The adoption of progenesis is less likely, however, when two parasites share the resource-limited intermediate host. These results show that parasites with complex developmental routes have transmission strategies and perception abilities that are more sophisticated than previously thought.