Svanbäck Richard, Schluter Dolph
Biodiversity Research Centre and Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
Am Nat. 2012 Jul;180(1):50-9. doi: 10.1086/666000. Epub 2012 May 22.
Phenotypic plasticity may be favored in generalist populations if it increases niche width, even in temporally constant environments. Phenotypic plasticity can increase the frequency of extreme phenotypes in a population and thus allow it to make use of a wide resource spectrum. Here we test the prediction that generalist populations should be more plastic than specialists. In a common-garden experiment, we show that solitary, generalist populations of threespine sticklebacks inhabiting small coastal lakes of British Columbia have a higher degree of morphological plasticity than the more specialized sympatric limnetic and benthic species. The ancestral marine stickleback showed low levels of plasticity similar to those of sympatric sticklebacks, implying that the greater plasticity of the generalist population has evolved recently. Measurements of wild populations show that those with mean trait values intermediate between the benthic and limnetic values indeed have higher morphological variation. Our data indicate that plasticity can evolve rapidly after colonization of a new environment in response to changing niche use.
如果表型可塑性能够增加生态位宽度，那么即使在时间上恒定的环境中，它在广食性种群中可能也会受到青睐。表型可塑性能够增加种群中极端表型的频率，从而使其能够利用广泛的资源谱。在此，我们检验了广食性种群应比专食性种群更具可塑性这一预测。在一项共同培养实验中，我们发现，栖息于不列颠哥伦比亚省小型沿海湖泊的三刺鱼独居广食性种群，比更具专业性的同域湖栖和底栖物种具有更高程度的形态可塑性。祖先海洋三刺鱼的可塑性水平较低，类似于同域三刺鱼，这意味着广食性种群更大的可塑性是近期进化而来的。对野生种群的测量表明，那些平均性状值介于底栖和湖栖值之间的种群确实具有更高的形态变异。我们的数据表明，在新环境定殖后，可塑性能够因生态位利用的变化而迅速进化。
