A growing body of research is focused on the extinction of parasite species in response to host endangerment and declines. Beyond the loss of parasite species richness, host extinction can impact apparent parasite host specificity, as measured by host richness or the phylogenetic distances among hosts. Such impacts on the distribution of parasites across the host phylogeny can have knock-on effects that may reshape the adaptation of both hosts and parasites, ultimately shifting the evolutionary landscape underlying the potential for emergence and the evolution of virulence across hosts. Here, we examine how the reshaping of host phylogenies through extinction may impact the host specificity of parasites, and offer examples from historical extinctions, present-day endangerment, and future projections of biodiversity loss. We suggest that an improved understanding of the impact of host extinction on contemporary host–parasite interactions may shed light on core aspects of disease ecology, including comparative studies of host specificity, virulence evolution in multi-host parasite systems, and future trajectories for host and parasite biodiversity.

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

越来越多的研究集中在寄生虫物种因宿主濒危和衰退而灭绝的问题上。除了寄生虫物种丰富度的丧失之外，宿主灭绝还会影响明显的寄生虫宿主特异性，这是通过宿主丰富度或宿主之间的系统发育距离来衡量的。这种对寄生虫在宿主系统发育中分布的影响可能会产生连锁反应，可能会重塑宿主和寄生虫的适应能力，最终改变宿主之间出现和毒力进化潜力的进化景观。在这里，我们研究通过灭绝重塑宿主系统发育如何影响寄生虫的宿主特异性，并提供历史灭绝、当前濒危和生物多样性丧失的未来预测的例子。我们建议，更好地了解宿主灭绝对当代宿主与寄生虫相互作用的影响可能有助于阐明疾病生态学的核心方面，包括宿主特异性的比较研究、多宿主寄生虫系统的毒力进化以及宿主和寄生虫的未来轨迹。寄生虫的生物多样性。

本文是“传染病宏观生态学：全球寄生虫多样性和动态”主题的一部分。