School of Biological Sciences, The University of Queensland, Brisbane, Australia.
Evolution. 2019 Jul;73(7):1330-1340. doi: 10.1111/evo.13716. Epub 2019 Mar 18.
Parasites often jump to and become established in a new host species. There is much evidence that the probability of such host shifts decreases with increasing phylogenetic distance between donor and recipient hosts, but the consequences of such preferential host switching remain little explored. We develop a computational model to investigate the dynamics of parasite host shifts in the presence of this phylogenetic distance effect. In this model, a clade of parasites evolves on an evolving clade of host species where parasites can cospeciate with their hosts, switch to new hosts, speciate within hosts or become extinct. Our model predicts that host phylogenies are major determinants of parasite distributions across trees. In particular, we predict that trees consisting of few large clades of host species and those with fast species turnover should harbor more parasites than trees with many small clades and those that diversify more slowly. Within trees, large clades are predicted to exhibit a higher fraction of infected species than small clades. We discuss our results in the light of recent cophylogenetic studies in a wide range of host-parasite systems.
寄生虫经常跳跃并在新的宿主物种中定居。有大量证据表明，这种宿主转移的可能性随着供体和受体宿主之间的系统发育距离的增加而降低，但这种优先宿主转换的后果仍很少被探索。我们开发了一个计算模型来研究在存在这种系统发育距离效应的情况下寄生虫宿主转移的动态。在这个模型中，寄生虫的一个进化枝在一个进化的宿主物种的进化枝上进化，寄生虫可以与它们的宿主协同进化，转而寄生到新的宿主上，在宿主内部形成新种，或灭绝。我们的模型预测，宿主系统发育是寄生虫在整个树上分布的主要决定因素。具体来说，我们预测由少数大的宿主物种进化枝组成的树和那些物种更替速度较快的树比那些有许多小进化枝和那些进化速度较慢的树应该有更多的寄生虫。在树内，大的进化枝预计比小的进化枝有更高比例的受感染物种。我们根据最近在广泛的宿主-寄生虫系统中进行的共进化研究来讨论我们的结果。
