Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland.
INVAS Biosecurity Ltd., 82 Lakelands Close, Stillorgan, Co Dublin, Ireland.
J Helminthol. 2020 Sep 14;94:e191. doi: 10.1017/S0022149X20000759.
Invasive species lose parasites in the process of invasion and tend to be less parasitized than conspecifics in the native range and sympatric native species in the invasive range (enemy release). We evaluated enemy release in an invasive freshwater fish in Ireland, common dace Leuciscus leuciscus, using helminth parasite community surveys at the core and front of the invasive range of common dace. Furthermore, we undertook a systematic literature review of helminth infection in common dace across its native range in Great Britain and Europe and invasive range in Ireland. The helminth parasite community survey revealed that invasive common dace were infected with fewer helminth species at the invasion front than at the core. Four helminth taxa - Acanthocephala, Monogenea, Digenea and Nematoda - were present in dace at the invasion core compared to only a single helminth species (Pomphorhynchus tereticollis) at the front. The systematic review revealed that invasive common dace in Ireland hosted fewer species of helminths than common dace in the native range. We report a total of three helminth species in common dace in Ireland compared to 24 in Great Britain and 84 in Continental Europe. Our results support the hypotheses that invasive populations are less parasitized than native populations and that more recently established populations host fewer parasites. However, we demonstrate that invasive species may continue to experience release from parasites long after initial invasion.
入侵物种在入侵过程中会失去寄生虫，并且与原生范围内的同种生物和入侵范围内的同域原生物种相比，它们受到的寄生虫感染通常较少（天敌释放）。我们评估了爱尔兰入侵淡水鱼类——普通亚口鱼（Leuciscus leuciscus）的天敌释放现象，方法是在普通亚口鱼入侵范围的核心区和前沿区进行寄生虫群落调查。此外，我们对普通亚口鱼在英国和欧洲原生范围以及爱尔兰入侵范围的寄生虫感染进行了系统文献综述。寄生虫群落调查显示，入侵的普通亚口鱼在入侵前沿的寄生虫物种数量少于核心区。在核心区，有 4 种寄生虫类群——棘头动物门、单殖吸虫门、复殖吸虫门和线虫门——存在于亚口鱼体内，而在前沿区只有 1 种寄生虫（Pomphorhynchus tereticollis）。系统综述表明，爱尔兰的入侵普通亚口鱼所携带的寄生虫物种少于原生范围内的普通亚口鱼。我们报告在爱尔兰的普通亚口鱼中共有 3 种寄生虫，而在英国有 24 种，在欧洲大陆有 84 种。我们的研究结果支持以下假设：入侵种群受到的寄生虫感染较少，而最近建立的种群寄生虫种类较少。然而，我们也证明，入侵物种在最初入侵后很长一段时间内仍可能继续从寄生虫中释放出来。
