Host lifespan and the evolution of resistance to multiple parasites
Host lifespan and the evolution of resistance to multiple parasites
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DOI：
10.1111/jeb.13025
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发表时间：
2017-03-01
影响因子：
2.1
通讯作者：
Boots, M.
中科院分区：
文献类型：
--
作者：
Donnelly, R.;White, A.;Boots, M.
宿主通常受到多种寄生虫的挑战，但迄今为止，关于耐药性进化的理论主要集中在单一感染上。我们开发了一系列模型，在假设寄生虫在宿主种群规模上由于重复感染而共存的情况下，研究多种寄生虫对耐药性进化的影响。通过这种方式，我们能够明确地检查生态动力学对进化结果的影响。我们使用我们的模型来解决宿主寿命如何影响对多种寄生虫的抗性投资的关键问题。我们表明，对代价高昂的耐药性的投资取决于免疫反应的特异性，以及局灶寄生虫是否比共循环寄生虫导致更急性的感染。一个关键的发现是，当免疫反应变得更加普遍时，对耐药性的投入总是会增加，而与最积极地利用宿主的是焦点寄生虫还是共循环寄生虫无关。在一般抗性和对相对急性的局灶性寄生虫的特异性抗性方面，寿命长的宿主总是比寿命短的宿主投入更多。然而，对于不像共循环寄生虫那样急性的寄生虫的特异性抗性，预计短命宿主的投入最多。我们表明，这些结果适用于任何防御模式，即无论是通过回避还是通过增加恢复，有或没有获得性免疫，还是通过获得性免疫本身。总的来说，我们的研究结果强调了考虑多种寄生虫在生态进化系统中确定最佳免疫投资的重要性。
Hosts are typically challenged by multiple parasites, but to date theory on the evolution of resistance has mainly focused on single infections. We develop a series of models that examine the impact of multiple parasites on the evolution of resistance under the assumption that parasites coexist at the host population scale as a consequence of superinfection. In this way, we are able to explicitly examine the impact of ecological dynamics on the evolutionary outcome. We use our models to address a key question of how host lifespan affects investment in resistance to multiple parasites. We show that investment in costly resistance depends on the specificity of the immune response and on whether or not the focal parasite leads to more acute infection than the co-circulating parasite. A key finding is that investment in resistance always increases as the immune response becomes more general independently of whether it is the focal or the co-circulating parasite that exploits the host most aggressively. Long-lived hosts always invest more than short-lived hosts in both general resistance and resistance that is specific to relatively acute focal parasites. However, for specific resistance to parasites that are less acute than co-circulating parasites it is the short-lived hosts that are predicted to invest most. We show that these results apply whatever the mode of defence, that is whether it is through avoidance or through increased recovery, with or without acquired immunity, or through acquired immunity itself. As a whole, our results emphasize the importance of considering multiple parasites in determining optimal immune investment in eco-evolutionary systems.