Predictable patterns of disruptive selection in stickleback in postglacial lakes
Predictable patterns of disruptive selection in stickleback in postglacial lakes
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DOI：
10.1086/587805
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发表时间：
2008-07-01
影响因子：
2.9
通讯作者：
Lau, On Lee
中科院分区：
文献类型：
--
作者：
Bolnick, Daniel I.;Lau, On Lee
破坏性选择通常被认为是相对罕见的，因为它是动态不稳定的，因此应该是暂时的。然而，频率依赖的相互作用，例如种内竞争，可能会稳定适应度最小值，并使破坏性选择变得更加常见。这种选择有助于解释遗传变异的维持，甚至可能有助于同域物种形成。因此，人们对确定破坏性选择最有可能发生的时间和地点非常感兴趣。在这里，我们发现温哥华岛 14 个湖泊中的三刺刺鱼（Gasterosteus aculeatus）的营养形态存在弱破坏性选择的总体趋势。选择是根据观察推断的，在湖内，具有中间鳃耙形态的鱼比表型极端的个体表现出更慢的生长。先前已证明这种选择是由于种内对替代资源的竞争而产生的。然而，并非所有环境都同样有利于破坏性选择，这种破坏性选择在中等规模的湖泊中最为强烈，那里的沿海和远洋猎物大致平衡。此外，与理论一致，我们发现营养性状的性二态性往往会减轻破坏性选择。这些结果表明，有可能预测最有可能经历破坏性选择的环境和人群类型。
Disruptive selection is often assumed to be relatively rare, because it is dynamically unstable and hence should be transient. However, frequency-dependent interactions such as intraspecific competition may stabilize fitness minima and make disruptive selection more common. Such selection helps explain the maintenance of genetic variation and may even contribute to sympatric speciation. There is thus great interest in determining when and where disruptive selection is most likely. Here, we show that there is a general trend toward weak disruptive selection on trophic morphology in three-spine stickleback (Gasterosteus aculeatus) in 14 lakes on Vancouver Island. Selection is inferred from the observation that, within a lake, fish with intermediate gill raker morphology exhibited slower growth than phenotypically extreme individuals. Such selection has previously been shown to arise from intraspecific competition for alternate resources. However, not all environments are equally conducive to disruptive selection, which was strongest in intermediate-sized lakes where both littoral and pelagic prey are roughly balanced. Also, consistent with theory, we find that sexual dimorphism in trophic traits tends to mitigate disruptive selection. These results suggest that it may be possible to anticipate the kinds of environments and populations most likely to experience disruptive selection.