Nematomorph parasites drive energy flow through a riparian ecosystem
Nematomorph parasites drive energy flow through a riparian ecosystem
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DOI：
10.1890/09-1565.1
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发表时间：
2011-01-01
期刊：
影响因子：
4.8
通讯作者：
Lafferty, Kevin D.
中科院分区：
文献类型：
--
作者：
Sato, Takuya;Watanabe, Katsutoshi;Lafferty, Kevin D.
寄生虫在自然系统中无处不在，生态系统水平的影响应与寄生虫改变的生物量或能量流的数量成正比。在这里，我们量化了一种操纵性寄生虫改变森林溪流生态系统能量流动的程度。在日本的一条源头河流中，如果被线虫寄生虫（Gordionus spp.）感染，骆驼蟋蟀和蚱蜢（直翅目）进入河流的可能性增加了20倍，这也是线虫操纵宿主寻找水源的有力证据，而寄生虫在那里以自由生活的成虫出现。濒临灭绝的日本鳟鱼（Salvelinus leucomaenis）很容易吃这些受感染的直翅目，这是由于他们的丰富，占60%的鳟鱼人口的年能量摄入量。鳟鱼在秋天生长得最快，这时线虫把能量丰富的直翅目动物赶进了小溪。当受感染的直翅目，鳟鱼不吃底栖无脊椎动物的比例，他们的丰度，导致潜在的级联，间接影响，通过森林流生态系统。这些结果提供了第一个定量证据，表明操纵性寄生虫可以显著改变生态系统中的能量流动。
Parasites are ubiquitous in natural systems and ecosystem-level effects should be proportional to the amount of biomass or energy flow altered by the parasites. Here we quantified the extent to which a manipulative parasite altered the flow of energy through a forest-stream ecosystem. In a Japanese headwater stream, camel crickets and grasshoppers (Orthoptera) were 20 times more likely to enter a stream if infected by a nematomorph parasite (Gordionus spp.), corroborating evidence that nematomorphs manipulate their hosts to seek water where the parasites emerge as free-living adults. Endangered Japanese trout (Salvelinus leucomaenis japonicus) readily ate these infected orthopterans, which due to their abundance, accounted for 60% of the annual energy intake of the trout population. Trout grew fastest in the fall, when nematomorphs were driving energy-rich orthopterans into the stream. When infected orthopterans were available, trout did not eat benthic invertebrates in proportion to their abundance, leading to the potential for cascading, indirect effects through the forest-stream ecosystem. These results provide the first quantitative evidence that a manipulative parasite can dramatically alter the flow of energy through and across ecosystems.