Clark Nicholas J, Clegg Sonya M
School of Veterinary Science, The University of Queensland, Gatton, Qld, 4343, Australia.
Environmental Futures Research Institute, Griffith University, Gold Coast, Qld, 4111, Australia.
Mol Ecol. 2017 Jun;26(11):3074-3086. doi: 10.1111/mec.14101. Epub 2017 Apr 3.
The range of hosts a pathogen infects (host specificity) is a key element of disease risk that may be influenced by both shared phylogenetic history and shared ecological attributes of prospective hosts. Phylospecificity indices quantify host specificity in terms of host relatedness, but can fail to capture ecological attributes that increase susceptibility. For instance, similarity in habitat niche may expose phylogenetically unrelated host species to similar pathogen assemblages. Using a recently proposed method that integrates multiple distances, we assess the relative contributions of host phylogenetic and functional distances to pathogen host specificity (functional-phylogenetic host specificity). We apply this index to a data set of avian malaria parasite (Plasmodium and Haemoproteus spp.) infections from Melanesian birds to show that multihost parasites generally use hosts that are closely related, not hosts with similar habitat niches. We also show that host community phylogenetic ß-diversity (Pßd) predicts parasite Pßd and that individual host species carry phylogenetically clustered Haemoproteus parasite assemblages. Our findings were robust to phylogenetic uncertainty, and suggest that phylogenetic ancestry of both hosts and parasites plays important roles in driving avian malaria host specificity and community assembly. However, restricting host specificity analyses to either recent or historical timescales identified notable exceptions, including a 'habitat specialist' parasite that infects a diversity of unrelated host species with similar habitat niches. This work highlights that integrating ecological and phylogenetic distances provides a powerful approach to better understand drivers of pathogen host specificity and community assembly.
病原体感染的宿主范围（宿主特异性）是疾病风险的一个关键因素，它可能受到宿主的系统发育历史和预期宿主的共享生态属性的影响。系统发育特异性指数根据宿主亲缘关系对宿主特异性进行量化，但可能无法捕捉到增加易感性的生态属性。例如，栖息地生态位的相似性可能会使系统发育上不相关的宿主物种接触到相似的病原体组合。我们使用一种最近提出的整合多种距离的方法，评估宿主系统发育距离和功能距离对病原体宿主特异性（功能 - 系统发育宿主特异性）的相对贡献。我们将这个指数应用于来自美拉尼西亚鸟类的禽疟原虫（疟原虫属和血变原虫属物种）感染数据集，以表明多宿主寄生虫通常利用亲缘关系密切的宿主，而非具有相似栖息地生态位的宿主。我们还表明，宿主群落系统发育β多样性（Pßd）可预测寄生虫的Pßd，并且单个宿主物种携带系统发育聚类的血变原虫寄生虫组合。我们的发现对系统发育不确定性具有稳健性，并表明宿主和寄生虫的系统发育祖先在推动禽疟宿主特异性和群落组装方面发挥着重要作用。然而，将宿主特异性分析限制在近期或历史时间尺度上发现了显著的例外情况，包括一种“栖息地专性”寄生虫，它感染了多种具有相似栖息地生态位的不相关宿主物种。这项工作强调，整合生态距离和系统发育距离为更好地理解病原体宿主特异性和群落组装的驱动因素提供了一种强有力的方法。
