Evolution of dispersal in a spatially heterogeneous population with finite patch sizes
Evolution of dispersal in a spatially heterogeneous population with finite patch sizes
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具有有限斑块大小的空间异质种群中的扩散演化
DOI：
10.1073/pnas.1915881117
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Wakano Joe Yuichiro
中科院分区：
文献类型：
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作者：
Parvinen Kalle;Ohtsuki Hisashi;Wakano Joe Yuichiro
扩散是生物体的基本生命史策略之一，因此了解塑造扩散特征的选择力非常重要。在赖特的岛屿模型中，即使分散的代价高昂，分散也是由于亲缘竞争而演变，并且传统上假设各地的生活条件都是相同的。为了研究空间异质性的影响，我们扩展了模型，使得斑块可以接收不同数量的移民，培育不同数量的个体，并赋予其中个体不同的繁殖效率。我们得到了适应度梯度的解析表达式，它表明方向选择由三个组成部分组成：在同质情况下，扩散的直接成本选择对抗扩散，而亲属竞争则促进扩散。额外的组成部分，空间异质性，更准确地说是所谓的相对繁殖潜力的方差，往往会选择反对扩散。我们还获得了适应度二阶导数的表达式，可用于确定是否存在破坏性选择：与同质情况不同，我们发现在异质情况下，通过进化分支可能出现性状分歧。我们的数值探索表明，斑块大小的差异比繁殖效率更能促进进化分支。我们的结果表明现实世界中现有的空间异质性作为扩散进化的关键决定因素的重要性。
Dispersal is one of the fundamental life-history strategies of organisms, so understanding the selective forces shaping the dispersal traits is important. In the Wright’s island model, dispersal evolves due to kin competition even when dispersal is costly, and it has traditionally been assumed that the living conditions are the same everywhere. To study the effect of spatial heterogeneity, we extend the model so that patches may receive different amounts of immigrants, foster different numbers of individuals, and give different reproduction efficiency to individuals therein. We obtain an analytical expression for the fitness gradient, which shows that directional selection consists of three components: As in the homogeneous case, the direct cost of dispersal selects against dispersal and kin competition promotes dispersal. The additional component, spatial heterogeneity, more precisely the variance of so-called relative reproductive potential, tends to select against dispersal. We also obtain an expression for the second derivative of fitness, which can be used to determine whether there is disruptive selection: Unlike the homogeneous case, we found that divergence of traits through evolutionary branching is possible in the heterogeneous case. Our numerical explorations suggest that evolutionary branching is promoted more by differences in patch size than by reproduction efficiency. Our results show the importance of the existing spatial heterogeneity in the real world as a key determinant in dispersal evolution.