Species interactions may vary considerably across space as a result of spatial and environmental gradients. With respect to host–parasite interactions, this suggests that host and parasite species may play different functional roles across the different networks they occur in. Using a global occurrence database of helminth parasites, we examine the conservation of species' roles using data on host–helminth interactions from 299 geopolitical locations. Defining species' roles in a two-dimensional space which captures the tendency of species to be more densely linked within species subgroups than between subgroups, we quantified species' roles in two ways, which captured if and which species' roles are conserved by treating species' utilization of this two-dimensional space as continuous, while also classifying species into categorical roles. Both approaches failed to detect the conservation of species' roles for a single species out of over 38 000 host and helminth parasite species. Together, our findings suggest that species' roles in host–helminth networks may not be conserved, pointing to the potential role of spatial and environmental gradients, as well as the importance of the context of the local host and helminth parasite community.

This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.

由于空间和环境梯度的原因，物种之间的相互作用可能在整个空间中存在很大差异。关于宿主 - 寄生虫相互作用，这表明宿主和寄生虫物种可能在它们出现的不同网络中发挥不同的功能作用。 使用蠕虫寄生虫的全球发生数据库，我们使用宿主数据检查物种角色的保护——来自 299 个地缘政治地点的蠕虫相互作用。在二维空间中定义物种的角色，该空间捕捉物种在物种亚群内比在亚群之间更紧密地联系的趋势，我们以两种方式量化了物种的角色，这两种方式捕捉了if和which通过将物种对该二维空间的利用视为连续的，同时还将物种分类为类别角色，物种的角色得到了保护。两种方法都未能从超过 38 000 种寄主和蠕虫寄生虫物种中检测到物种对单一物种的保护作用。总之，我们的研究结果表明，物种在宿主 - 蠕虫网络中的作用可能不会得到保护，这表明空间和环境梯度的潜在作用，以及当地宿主和蠕虫寄生虫群落背景的重要性。

本文是主题问题“传染病宏观生态学：全球寄生虫多样性和动态”的一部分。