Data from: Adaptive plasticity and genetic divergence in feeding efficiency during parallel adaptive radiation of whitefish (Coregonus spp.)

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 postglacial 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.

在重复发生的适应性辐射（adaptive radiation）中，平行表型分化的成因可分为两类：一是针对相似歧化选择机制的平行遗传分化，二是针对反复出现的对比环境产生的等价表型可塑性（phenotypic plasticity）响应。在冰期后鱼类类群中，沿底栖-敞水生境轴（benthic-limnetic habitat axis）的重复表型分化现象十分常见。本研究选取源自瑞士两个湖泊的两组底栖-敞水白鲑物种对，采用共同花园（common garden）实验设计，其中一组物种对设置了交互食物处理，以此实验探究底栖猎物的摄食效率是否具有遗传基础，或受表型可塑性调控（或两者兼具）。为此，我们向实验鱼投喂部分掩埋于沙中的蚊幼虫，并对多项摄食效率指标进行了测定。本研究结果显示，摄食效率同时存在遗传分化与表型可塑性分化：以底栖食物饲养的表型底栖物种，在捕食底栖猎物时的觅食效率最高。这表明，针对可遗传性状的歧化自然选择与适应性表型可塑性，均为推动适应性辐射中表型分化的重要机制。