Parker Benjamin J, McLean Ailsa H C, Hrček Jan, Gerardo Nicole M, Godfray H Charles J
Department of Zoology, University of Oxford, Oxford, UK
Department of Zoology, University of Oxford, Oxford, UK.
Biol Lett. 2017 May;13(5). doi: 10.1098/rsbl.2017.0016.
Animal-associated microbial communities have important effects on host phenotypes. Individuals within and among species differ in the strains and species of microbes that they harbour, but how natural selection shapes the distribution and abundance of symbionts in natural populations is not well understood. Symbionts can be beneficial in certain environments but also impose costs on their hosts. Consequently, individuals that can or cannot associate with symbionts will be favoured under different ecological circumstances. As a result, we predict that individuals within a species vary in terms of how well they accept and maintain symbionts. In pea aphids, the frequency of endosymbionts varies among host-plant-associated populations ('biotypes'). We show that aphid genotypes from different biotypes vary in how well they accept and maintain symbionts after horizontal transfer. We find that aphids from biotypes that frequently harbour symbionts are better able to associate with novel symbionts than those from biotypes that less frequently harbour symbionts. Intraspecific variation in the ability of hosts to interact with symbionts is an understudied factor explaining patterns of host-symbiont association.
与动物相关的微生物群落对宿主表型具有重要影响。物种内部和物种之间的个体所携带的微生物菌株和种类存在差异，但自然选择如何塑造自然种群中共生体的分布和丰度，目前尚不清楚。共生体在某些环境中可能有益，但也会给宿主带来成本。因此，在不同的生态环境下，能够或不能与共生体共生的个体将受到青睐。结果，我们预测一个物种内的个体在接受和维持共生体的能力方面存在差异。在豌豆蚜中，内共生体的频率在与宿主植物相关的种群（“生物型”）中有所不同。我们表明，来自不同生物型的蚜虫基因型在水平转移后接受和维持共生体的能力方面存在差异。我们发现，经常携带共生体的生物型中的蚜虫比很少携带共生体的生物型中的蚜虫更能与新的共生体共生。宿主与共生体相互作用能力的种内变异是一个尚未充分研究的因素，可用于解释宿主 - 共生体关联模式。
