Functional basis of ecological divergence in sympatric stickleback.
Functional basis of ecological divergence in sympatric stickleback.
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DOI：
10.1186/1471-2148-13-277
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发表时间：
2013-12-31
影响因子：
3.4
通讯作者：
Wainwright PC
中科院分区：
文献类型：
--
作者：
McGee MD;Schluter D;Wainwright PC
密切相关物种的生态分化的进化是适应性辐射的关键组成部分。然而，在大多数适应性辐射的例子中，生态分歧的机制基础仍不清楚。一个典型的例子是不列颠哥伦比亚省的年轻底栖和湖沼刺鱼对。在每一对中，底栖物种以滨海大型无脊椎动物为食，而湖沼以中上层浮游动物为食。先前的研究表明，在短期摄食试验和长期围栏研究中，底栖动物和湖沼动物在自身资源上表现出增强的性能，但在其他物种资源上表现较差。我们利用应用于形态特征的鱼类摄食生物力学模型，研究了来自不列颠哥伦比亚省帕克斯顿湖的一对刺鱼生态分化的功能基础。我们使用喂鱼的高速视频检查了形态差异的后果。底栖刺鱼具有预示高吸力产生能力的形态特征，包括极度肥大的轴侧肌肉组织。相比之下，湖沼刺鱼具有被认为可以增强捕获逃避的浮游猎物的特征，包括比底栖动物更大的下颌突出以及下颌张开杠杆系统和鳃盖四连杆机构具有更大的位移优势。运动学数据支持形态学分析的预期，即湖沼刺鱼比底栖鱼表现出更快的攻击和更大的下巴突出，而底栖鱼对附着的猎物施加更大的吸力。我们揭示了一系列以前未知的复杂形态特征，这些特征影响同域刺鱼的快速生态分化。这些结果表明，冰期后棘鱼的分化涉及许多功能系统，并显示了研究适应性辐射中表型分化的功能后果的价值。
The evolution of ecological divergence in closely related species is a key component of adaptive radiation. However, in most examples of adaptive radiation the mechanistic basis of ecological divergence remains unclear. A classic example is seen in the young benthic and limnetic stickleback species pairs of British Columbia. In each pair the benthic species feeds on littoral macroinvertebrates whereas the limnetic feeds on pelagic zooplankton. Previous studies indicate that in both short-term feeding trials and long-term enclosure studies, benthics and limnetics exhibit enhanced performance on their own resource but fare more poorly on the other species’ resource. We examined the functional basis of ecological divergence in the stickleback species pair from Paxton Lake, BC, using biomechanical models of fish feeding applied to morphological traits. We examined the consequences of morphological differences using high speed video of feeding fish. Benthic stickleback possess morphological traits that predict high suction generation capacity, including greatly hypertrophied epaxial musculature. In contrast, limnetic stickleback possess traits thought to enhance capture of evasive planktonic prey, including greater jaw protrusion than benthics and greater displacement advantage in both the lower jaw-opening lever system and the opercular four-bar linkage. Kinematic data support the expectations from the morphological analysis that limnetic stickleback exhibit faster strikes and greater jaw protrusion than benthic fish, whereas benthics exert greater suction force on attached prey. We reveal a previously unknown suite of complex morphological traits that affect rapid ecological divergence in sympatric stickleback. These results indicate that postglacial divergence in stickleback involves many functional systems and shows the value of investigating the functional consequences of phenotypic divergence in adaptive radiation.