Experimental exposure of juvenile snails (Potamopyrgus antipodarum ) to infection by trematode larvae (Microphallus sp.): infectivity, fecundity compensation and growth
Experimental exposure of juvenile snails (Potamopyrgus antipodarum ) to infection by trematode larvae (Microphallus sp.): infectivity, fecundity compensation and growth
复制标题
幼年蜗牛（Potamopyrgus antipodarum）暴露于吸虫幼虫（Microphallus sp.）感染的实验：感染性、繁殖力补偿和生长
作者：
Amy C. Krist;C. Lively
摘要导致宿主阉割的宿主与寄生虫相互作用在进化上类似于捕食者与猎物的相互作用，因为这两种相互作用都会终止宿主或猎物的繁殖。然而，宿主-寄生虫相互作用不同于捕食者-猎物相互作用，因为受感染的宿主仍然活着，并且可能在阉割完成之前对其生活史策略进行调整。在这里，我们暴露的幼年蜗牛（Potamopyrgus antipodarum）感染的双殖吸虫（Microphallus sp.）以确定：（1）生殖前个体可能被感染，（2）暴露于感染的个体将资源转移到早期生殖（生殖力补偿），（3）感染个体相对于未感染个体表现出改变的生长速率。我们发现，青少年容易感染，因此，P. antipodarum可以选择在感染风险高的人群中较早成熟。我们还发现，繁殖力补偿不会发生在这种蜗牛。最后，我们发现，感染了微茎线虫的蜗牛表现出改变的生长速度;个体感染的青少年有较低的生长速度，比未感染的蜗牛更小。这些结果表明，生长的吸虫寄生虫的感染，但未感染的蜗牛的繁殖是不诱导暴露于吸虫卵的改变。
Abstract Host-parasite interactions that result in host castration are evolutionarily similar to predator-prey interactions because both interactions terminate reproduction for the host or prey. Yet, host-parasite interactions differ from predator-prey interactions in that infected hosts remain alive and potentially can make adjustments to their life-history strategy before castration is complete. Here we exposed juvenile snails (Potamopyrgus antipodarum) to infection by a digenetic trematode (Microphallus sp.) in order to determine whether: (1) pre-reproductive individuals could be infected, (2) individuals that were exposed to infection shifted resources to early reproduction (fecundity compensation), and (3) infected individuals exhibit altered growth rates relative to uninfected individuals. We found that juveniles are susceptible to infection; hence P. antipodarum could be selected for earlier maturation in populations where the risk of infection is high. We also found that fecundity compensation does not occur in this snail. Finally, we found that Microphallus-infected snails exhibit altered growth rates; individuals infected as juveniles have lower growth rates and are smaller than uninfected snails. These results suggest that growth is altered by infection of a trematode parasite but reproduction in uninfected snails is not induced by exposure to trematode eggs.