Parasites are often key players in biological invasions since they can mediate the impact of host invasions or can themselves become invasive species. However, the nature and extent of parasite‐mediated invasions are often difficult to delineate. Here, we used individual‐based, weighted bipartite networks to study the roles (degrees of interactions of individuals in a modular network according to their within‐ and among‐module connections) played by native and invasive host individuals to their parasite communities. We studied two phylogenetically and ecologically close fish species, Mugil cephalus s.l. and Planiliza haematocheilus (Teleostei: Mugilidae). Planiliza haematocheilus is native to the Sea of Japan and invasive in the Sea of Azov whereas, M. cephalus s.l. is native to both seas. Based on the common evolutionary history that drives native host–parasite networks, we hypothesised that 1) native networks have higher modularity than invaded ones; and 2) invasive hosts in the invaded area play a peripheral role to structure parasite communities. We analysed the whole parasite community and subsets based on transmission strategy and host specificity of the parasite species to establish whether modularity and host roles are related to these features in the native and invaded areas. All networks were found to be modular. However, modularity tended to be higher in networks of the native area rather than those of the invaded area. Host individuals of both fish species played similar roles in the native area, whereas invasive hosts played a peripheral role in the networks of the invaded area. We propose that long‐term monitoring of the roles of invasive hosts in parasite communities can be a useful proxy for estimating the maturity of the establishment of the invasive hosts in an ecosystem.

中文翻译：

---

原生和侵入性宿主在宿主-寄生虫网络中扮演不同的角色

寄生虫通常是生物入侵的关键参与者，因为它们可以调节宿主入侵的影响，或者它们本身可以成为入侵物种。然而，寄生虫介导的入侵的性质和程度通常难以描述。在这里，我们使用基于个体的加权二分网络来研究本地和入侵宿主个体对其寄生虫社区所扮演的角色（模块化网络中个体的交互程度，根据其模块内和模块间的连接）。我们研究了两种系统发育和生态学上接近的鱼类，Mugil cephalus sl 和 Planiliza haematocheilus（Teleostei：Mugilidae）。Planiliza haematocheilus 原产于日本海并侵入亚速海，而 M. cephalus sl 原产于两海。基于驱动原生宿主 - 寄生虫网络的共同进化历史，我们假设：1）原生网络比入侵网络具有更高的模块化；2) 入侵区域的入侵宿主在构建寄生虫群落方面发挥外围作用。我们根据寄生虫物种的传播策略和宿主特异性分析了整个寄生虫群落和子集，以确定模块化和宿主角色是否与本地和入侵区域的这些特征有关。发现所有网络都是模块化的。然而，在原生地区的网络中，模块性往往高于入侵地区的网络。两种鱼类的寄主个体在本地地区扮演着相似的角色，而入侵宿主在入侵地区的网络中扮演着外围角色。