Division of Aquatic Ecology & Evolution, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland.
J Evol Biol. 2013 Mar;26(3):483-98. doi: 10.1111/jeb.12063. Epub 2013 Jan 3.
Parallel phenotypic divergence in replicated adaptive radiations could either result from parallel genetic divergence in response to similar divergent selection regimes or from equivalent phenotypically plastic response to the repeated occurrence of contrasting environments. In post-glacial fish, replicated divergence in phenotypes along the benthic-limnetic habitat axis is commonly observed. Here, we use two benthic-limnetic species pairs of whitefish from two Swiss lakes, raised in a common garden design, with reciprocal food treatments in one species pair, to experimentally measure whether feeding efficiency on benthic prey has a genetic basis or whether it underlies phenotypic plasticity (or both). To do so, we offered experimental fish mosquito larvae, partially burried in sand, and measured multiple feeding efficiency variables. Our results reveal both, genetic divergence as well as phenotypically plastic divergence in feeding efficiency, with the phenotypically benthic species raised on benthic food being the most efficient forager on benthic prey. This indicates that both, divergent natural selection on genetically heritable traits and adaptive phenotypic plasticity, are likely important mechanisms driving phenotypic divergence in adaptive radiation.
在复制的适应性辐射中，平行的表型趋异可能是由于对相似的趋异选择环境的平行遗传趋异，或者是由于对反复出现的对比环境的等效表型可塑性反应所致。在冰川后鱼类中，沿着底栖-洄游生境轴的表型趋异在复制中很常见。在这里，我们使用来自瑞士两个湖泊的两种底栖-洄游白鲑物种对，在一个共同的花园设计中饲养，并在一个物种对中进行了互惠的食物处理，来实验测量在底栖猎物上的摄食效率是否具有遗传基础，或者它是否是表型可塑性的基础（或者两者兼而有之）。为此，我们为实验鱼提供了部分埋在沙子里的蚊子幼虫，并测量了多个摄食效率变量。我们的结果揭示了摄食效率的遗传趋异和表型可塑性趋异，以底栖食物为食的表型底栖物种是底栖猎物的最有效觅食者。这表明，对遗传上可遗传性状的趋异自然选择和适应性表型可塑性，都是推动适应性辐射中表型趋异的重要机制。
