Centre d'Ecologie Fonctionnelle et Evolutive, UMR CNRS 5175, 1, 1919 route de Mende, 34293 Montpellier cedex 5, France.
Int J Parasitol. 2013 Sep;43(10):795-803. doi: 10.1016/j.ijpara.2013.04.009. Epub 2013 Jul 11.
We investigated the host specificity of two cryptic microsporidian species (Anostracospora rigaudi and Enterocytospora artemiae) infecting invasive (Artemia franciscana) and native (Artemia parthenogenetica) hosts in sympatry. Anostracospora rigaudi was on average four times more prevalent in the native host, whereas E. artemiae was three times more prevalent in the invasive host. Infection with An. rigaudi strongly reduced female reproduction in both host species, whereas infection with E. artemiae had weaker effects on female reproduction. We contrasted microsporidian prevalence in native A. franciscana populations (New World) and in both invaded and non-invaded Artemia populations (Old World). At a community level, microsporidian prevalence was twice as high in native compared with invasive hosts, due to the contrasting host-specificity of An. rigaudi and E. artemiae. At a higher biogeographical level, microsporidian prevalence in A. franciscana did not differ between the invaded populations and the native populations used for the introduction. Although E. artemiae was the only species found both in New and Old World populations, no evidence of its co-introduction with the invasive host was found in our experimental and phylogeographic tests. These results suggest that the success of A. franciscana invasion is probably due to a lower susceptibility to virulent microsporidian parasites rather than to decreased microsporidian prevalence compared with A. parthenogenetica or to lower microsporidian virulence in introduced areas.
我们调查了两种隐生性微孢子虫（Anostracospora rigaudi 和 Enterocytospora artemiae）在入侵种（Artemia franciscana）和本地种（Artemia parthenogenetica）宿主中共生时的宿主特异性。Anostracospora rigaudi 在本地宿主中的平均流行率高四倍，而 E. artemiae 在入侵宿主中的流行率高三倍。感染 An. rigaudi 强烈降低了两种宿主的雌性繁殖力，而感染 E. artemiae 对雌性繁殖力的影响较弱。我们比较了微孢子虫在本地 A. franciscana 种群（新世界）和入侵和非入侵 Artemia 种群（旧世界）中的流行率。在群落水平上，由于 An. rigaudi 和 E. artemiae 的宿主特异性相反，本地宿主的微孢子虫流行率比入侵宿主高两倍。在更高的生物地理水平上，入侵种群和用于引入的本地种群的 A. franciscana 中的微孢子虫流行率没有差异。尽管 E. artemiae 是在新世界和旧世界种群中都发现的唯一物种，但在我们的实验和系统地理学测试中没有发现其与入侵宿主共同引入的证据。这些结果表明，A. franciscana 入侵的成功可能是由于对毒力强的微孢子虫寄生虫的敏感性较低，而不是与 A. parthenogenetica 相比微孢子虫流行率降低或引入地区的微孢子虫毒力降低所致。
