Université de Bourgogne, UMR CNRS 5561 Biogéosciences, Equipe Ecologie Evolutive, 6 Bd Gabriel, 21000 Dijon, France.
Parasitology. 2010 Jan;137(1):137-47. doi: 10.1017/S0031182009991077. Epub 2009 Sep 21.
Biological invasions expose parasites to new invasive hosts in addition to their local hosts. However, local parasites are often less successful in infecting and exploiting their new hosts. This may have major consequences for the competitive ability of hosts, and finally on the fate of the parasite-host community. In Burgundy (Eastern France), the acanthocephalan parasite, Pomphorhynchus laevis, infects 2 amphipod species living in sympatry: the native Gammarus pulex and the invasive Gammarus roeseli. While P. laevis affects the behaviour and the immunity of G. pulex, G. roeseli seems unaffected by the infection. In this study, we examined in detail the ability of the parasite to affect the immune system and resource storage of both gammarid species. We found that the infection was associated with a general decrease of the prophenoloxidase activity, haemocyte density, resistance to an artificial bacterial infection and level of sugar reserves in G. pulex, but not in G. roeseli. These results demonstrate a differential ability of P. laevis to exploit its local and its invasive gammarid hosts. Potential mechanisms of these differential physiological alterations and their potential consequences on the coexistence of both gammarid species in sympatry are discussed.
生物入侵除了使寄生虫接触到新的入侵宿主外，还会使寄生虫接触到当地宿主。然而，当地寄生虫往往在感染和利用新宿主方面的成功率较低。这可能对宿主的竞争能力产生重大影响，并最终影响寄生虫-宿主群落的命运。在法国东部的勃艮第地区，棘头虫寄生虫 Pomphorhynchus laevis 感染了两种共生的片脚类动物：本地的螯虾 Gammarus pulex 和入侵的螯虾 Gammarus roeseli。虽然 P. laevis 会影响 G. pulex 的行为和免疫力，但 G. roeseli 似乎不受感染的影响。在这项研究中，我们详细研究了寄生虫影响两种螯虾物种免疫系统和资源储存的能力。我们发现，感染与螯虾 G. pulex 的原酚氧化酶活性、血球密度、对人工细菌感染的抵抗力和糖储备水平的普遍下降有关，但在 G. roeseli 中则没有。这些结果表明，P. laevis 有能力利用其当地和入侵的螯虾宿主。讨论了这些差异生理变化的潜在机制及其对两种螯虾在同域共存的潜在影响。
