Dispersal in a patchy landscape reveals contrasting determinants of infection in a wild avian malaria system

1. Understanding exactly when, where and how hosts become infected with parasites is critical to understanding host-parasite coevolution. However, for host-parasite systems in which hosts or parasites are mobile (for example vector-borne diseases), the spatial location of infection, and the relative importance of parasite exposure at successive host life-history stages, are often uncertain. 2. Here, using a six-year longitudinal dataset from a spatially referenced population of blue tits, we test the extent to which infection by avian malaria parasites is determined by conditions experienced at natal or breeding sites, as well as by postnatal dispersal between the two. 3. We show that the location and timing of infection differs markedly between two sympatric malaria parasite species. For one species (P. circumflexum), our analyses indicate that infection occurs after birds have settled on breeding territories, and because the distribution of this parasite is temporally stable, hosts co...1. 精准解析宿主感染寄生虫的时间、位点与路径，是阐释宿主-寄生虫协同进化（host-parasite coevolution）机制的核心前提。然而，对于宿主或寄生虫具有移动性的宿主-寄生虫系统（例如虫媒传染病（vector-borne diseases）），感染的空间分布，以及宿主连续生活史阶段中寄生虫暴露的相对重要性，往往难以确定。2. 本研究依托一项针对空间参考种群（spatially referenced population）蓝山雀（blue tits）的6年纵向监测数据集（longitudinal dataset），探究禽疟原虫（avian malaria parasites）的感染程度分别受繁殖地、出生地（natal site）环境，以及二者间产后扩散（postnatal dispersal）过程的影响程度。3. 本研究发现，两种同域分布的疟原虫物种的感染位点与感染时间存在显著差异。针对其中一种疟原虫（P. circumflexum），分析结果显示其感染发生于鸟类定居繁殖领地之后；由于该寄生虫的分布具有时间稳定性，宿主...