The effect of spatial heterogeneity and parasites on the evolution of host diversity
The effect of spatial heterogeneity and parasites on the evolution of host diversity
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DOI：
10.1098/rspb.2003.2556
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发表时间：
2004-01-07
影响因子：
4.7
通讯作者：
Buckling, A
中科院分区：
文献类型：
--
作者：
Brockhurst, MA;Rainey, PB;Buckling, A
空间异质性和剥削者（寄生虫和捕食者）都被认为是推动人口多样化的关键生态因素。然而，尚不清楚这些因素如何相互作用。我们使用常见的植物定殖细菌荧光假单胞菌来解决这个问题，该细菌已被证明在实验室微观世界中繁殖时能够迅速多样化为空间生态位专业基因型。复制群体在有或没有病毒寄生虫（噬菌体）的空间同质和异质环境（分别为摇动和静态微观世界）中进化了大约 60 个细菌世代。与之前的发现一致，开发者通过放松资源竞争的强度来减少异构环境中的多样性。相比之下，剥削者在同质环境中增加了多样性，而在同质环境中，通过资源竞争几乎没有多样化。竞争实验表明，多样性的增加是剥削者抵抗力和竞争能力之间适应性权衡的结果。在这两种环境中，剥削者都增加了异域多样性，这可能是由于种群之间对抵抗力的不同选择的结果。噬菌体增加了同质环境中的总多样性，但在异质环境中没有净效应。在未来的研究中解决多样化和共存问题时，需要考虑关键生态变量之间的这种相互作用。
Both spatial heterogeneity and exploiters (parasites and predators) have been implicated as key ecological factors driving population diversification. However, it is unclear how these factors interact. We addressed this question using the common plant-colonizing bacterium Pseudomonas fluoreseens, which has been shown to diversify rapidly into spatial niche-specialist genotypes when propagated in laboratory microcosms. Replicate populations were evolved in spatially homogeneous and heterogeneous environments (shaken and static microcosms, respectively) with and without viral parasites (bacteriophage) for approximately 60 bacterial generations. Consistent with previous findings, exploiters reduced diversity in heterogeneous environments by relaxing the intensity of resource competition. By contrast, exploiters increased diversity in homogeneous environments where there was little diversification through resource competition. Competition experiments revealed this increase in diversity to be the result of fitness trade-offs between exploiter resistance and competitive ability. In both environments, exploiters increased allopatric diversity, presumably as a result of divergent selection for resistance between populations. Phage increased total diversity in homogeneous environments, but had no net effect in heterogeneous environments. Such interactions between key ecological variables need to be considered when addressing diversification and coexistence in future studies.