Department of Ecology and Evolutionary Biology, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan.
J Fish Biol. 2012 Jan;80(1):131-46. doi: 10.1111/j.1095-8649.2011.03161.x. Epub 2011 Dec 1.
Sexual dimorphism in geometric body shape and external morphology was compared between marine and stream-resident forms of three-spined stickleback Gasterosteus aculeatus collected from North America and Japan. Some aspects of sexual dimorphism were shared between ecotypes: males had larger heads than females with no significant effect of ecotype on the magnitude of sexual dimorphism. By contrast, a significant sex-by-ecotype interaction was found for body depth. Males tended to have deeper bodies than females in both forms, but the magnitude of sexual dimorphism was reduced in stream-resident forms. Although females were generally larger in standard length and had larger pelvic girdles, significant sexual dimorphism in these traits was not consistently found across populations or ecotypes. These results suggest that some aspects of sexual dimorphism were shared between ecotypes, while others were unique to each population. The results further suggest that ecology may influence the evolution of sexual dimorphism in some external morphological traits, such as body depth.
比较了来自北美的海洋和溪流定居形式的三种棘刺鱼的几何体型和外部形态的性别二态性。 一些性二态性方面在生态型之间是共同的：雄性的头部比雌性大，但生态型对性二态性的程度没有显著影响。 相比之下，对于体深，发现了一个显著的性别与生态型的相互作用。 在两种形式中，雄性的身体通常比雌性深，但在溪流定居形式中，性二态性的程度降低了。 尽管雌性在标准长度上通常更大，并且具有更大的骨盆带，但在种群或生态型中并不总是发现这些特征的显著性二态性。 这些结果表明，一些性二态性方面在生态型之间是共同的，而其他方面则是每个种群所特有的。 结果还表明，生态可能会影响某些外部形态特征（例如身体深度）的性二态性的进化。
