Two morphotypes of lacustrine threespine sticklehack, Gasterosteus aculeatus, in Benka Lake, Alaska
Two morphotypes of lacustrine threespine sticklehack, Gasterosteus aculeatus, in Benka Lake, Alaska
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DOI：
10.1007/bf00002526
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发表时间：
1996-04-01
影响因子：
1.4
通讯作者：
Baker, JA
中科院分区：
文献类型：
--
作者：
Cresko, WA;Baker, JA
在淡水鱼类中，最近已认识到身体形态和营养结构多样化的常见模式。两套不同的共现特征似乎使鱼类能够有效地以底栖无脊椎动物或浮游生物为食。对于三刺刺鱼 Gasterosteus aculeatus，这些特征组被标记为“底栖”和“湖沼”。这些形态在几个形态特征上有所不同，湖沼具有更纺锤形的形状、更大的眼睛、更长且更多的鳃耙以及更小、更管状的嘴。底栖和湖沼三脊刺鱼通常见于异域或近域，较少见于同域。在三刺刺鱼的范围内，大约有数万个湖泊种群，仅在不列颠哥伦比亚省乔治亚海峡的一个小区域内的六个湖泊中发现了底栖和湖沼形式的同域分布。我们提出了第一个证据，证明不列颠哥伦比亚省以外的三刺刺鱼存在同域形态类型。我们研究了这种多样化的性质和程度，并对这些形态类型的同域出现提出了可能的解释。我们还探讨了尽管存在数千个明显合适的湖泊，但记录的三刺鱼的同域底栖和湖沼形式数量较少的可能原因。
Within freshwater fishes, a common pattern of diversification of body form and trophic structure has recently been recognized. Two different suites of co-occurring characters appear to allow fish to efficiently forage on either benthic invertebrates or plankton. For threespine stickleback, Gasterosteus aculeatus, these suites of characters have been labeled 'benthic' and 'limnetic'. The forms differ in several morpholoical traits, with the limnetic having a more fusiform shape, larger eyes, longer and more numerous gill rakers, and a smaller more tubular mouth. Benthic and limnetic threespine stickleback are usually found in allopatry or parapatry, and less frequently in sympatry. Within the range of the threespine stickleback, which comprises perhaps tens of thousands of lacustrine populations, the sympatric occurrence of the benthic and limnetic forms has only been established for six lakes within a small region of the Strait of Georgia, British Columbia. We present the first evidence for the presence of sympatric morphotypes of threespine stickleback outside of British Columbia. We examine the nature and extent of this diversification, and present possible explanations for the sympatric occurrence of these morphotypes. We also explore possible reasons for the small number of documented sympatric benthic and limnetic forms of threespine stickleback despite the existence of thousands of apparently suitable lakes.