Metapopulation Research Group, PO Box 65 (Viikinkaari 1), Department of Biosciences, FI-00014 University of Helsinki, Finland.
Evolution. 2013 Nov;67(11):3362-70. doi: 10.1111/evo.12182. Epub 2013 Jul 11.
Trade-offs in life-history traits is a central tenet in evolutionary biology, yet their ubiquity and relevance to realized fitness in natural populations remains questioned. Trade-offs in pathogens are of particular interest because they may constrain the evolution and epidemiology of diseases. Here, we studied life-history traits determining transmission in the obligate fungal pathogen, Podosphaera plantaginis, infecting Plantago lanceolata. We find that although traits are positively associated on sympatric host genotypes, on allopatric host genotypes relationships between infectivity and subsequent transmission traits change shape, becoming even negative. The epidemiological prediction of this change in life-history relationships in allopatry is lower disease prevalence in newly established pathogen populations. An analysis of the natural pathogen metapopulation confirms that disease prevalence is lower in newly established pathogen populations and they are more prone to go extinct during winter than older pathogen populations. Hence, life-history trade-offs mediated by pathogen local adaptation may influence epidemiological dynamics at both population and metapopulation levels.
生活史特征的权衡是进化生物学的一个核心原则，但它们在自然种群中实现适应性的普遍性和相关性仍然存在争议。病原体之间的权衡特别有趣，因为它们可能限制疾病的进化和流行病学。在这里，我们研究了决定专性真菌病原体 Podosphaera plantaginis 感染 Plantago lanceolata 传播的生活史特征。我们发现，尽管在同域的宿主基因型上特征呈正相关，但在异域的宿主基因型上，侵染性和随后的传播特征之间的关系发生了变化，甚至变成了负相关。这种异域生活史关系变化的流行病学预测是新建立的病原体种群中疾病流行率较低。对自然病原体复合种群的分析证实，新建立的病原体种群中的疾病流行率较低，并且它们在冬季比旧的病原体种群更容易灭绝。因此，由病原体局部适应介导的生活史权衡可能会影响种群和复合种群水平的流行病学动态。
