Sarquis-Adamson Yanina, MacDougall-Shackleton Elizabeth A
Department of Biology , University of Western Ontario , London , Ontario , Canada.
R Soc Open Sci. 2016 Aug 10;3(8):160216. doi: 10.1098/rsos.160216. eCollection 2016 Aug.
Hosts and parasites interact on both evolutionary and ecological timescales. The outcome of these interactions, specifically whether hosts are more resistant to their local parasites (sympatric) than to parasites from another location (allopatric), is likely to affect the spread of infectious disease and the fitness consequences of host dispersal. We conducted a cross-infection experiment to determine whether song sparrows () have an advantage in dealing with sympatric parasites. We captured birds from two breeding sites 437 km apart, and inoculated them with avian malaria ( spp.) cultured either from their capture site or from the other site. Infection risk was lower for birds exposed to sympatric than to allopatric lineages, suggesting that song sparrows may have a home-field advantage in defending against local parasite strains. This pattern was more pronounced at one capture site than at the other, consistent with mosaic models of host-parasite interactions. Home-field advantage may arise from evolutionary processes, whereby host populations become adapted to their local parasites, and/or from ecological interactions, whereby host individuals develop resistance to the local parasites through previous immune exposure. Our findings suggest that greater susceptibility to novel parasites may represent a fitness consequence of natal dispersal.
宿主与寄生虫在进化和生态时间尺度上相互作用。这些相互作用的结果，特别是宿主对本地寄生虫（同域的）的抗性是否高于对来自其他地点的寄生虫（异域的），可能会影响传染病的传播以及宿主扩散对适合度的影响。我们进行了一项交叉感染实验，以确定歌带鹀在应对同域寄生虫方面是否具有优势。我们从相距437公里的两个繁殖地点捕获鸟类，并给它们接种从其捕获地点或另一个地点培养的禽疟原虫（疟原虫属）。暴露于同域谱系的鸟类感染风险低于暴露于异域谱系的鸟类，这表明歌带鹀在抵御本地寄生虫菌株方面可能具有主场优势。这种模式在一个捕获地点比在另一个捕获地点更明显，这与宿主 - 寄生虫相互作用的镶嵌模型一致。主场优势可能源于进化过程，即宿主种群适应其本地寄生虫，和/或源于生态相互作用，即宿主个体通过先前的免疫暴露对本地寄生虫产生抗性。我们的研究结果表明，对新寄生虫的易感性增加可能是出生扩散对适合度的一个影响。
