Meyer Christiane I, Kaufman Robert, Cech Joseph J
Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
Naturwissenschaften. 2006 Oct;93(10):495-9. doi: 10.1007/s00114-006-0134-x. Epub 2006 Jul 8.
Variation in melanin patterns among individuals, populations, and species is common in fishes of the genus Xiphophorus. In the variable platyfish, Xiphophorus variatus, variation in metabolic rate is associated with melanin coloration and the color morphs appear to be physiological specialists adapted to particular environmental conditions. This study investigates whether a melanin polymorphism in the green swordtail, Xiphophorus helleri, is likewise associated with variation in metabolic rate. We measured metabolic rate as oxygen consumption rate of both adult male and juvenile X. helleri in static respirometers. The oxygen consumption rate does not differ significantly between the spotted and nonspotted morphs in either group, suggesting that-unlike in X. variatus-selection on metabolic rate is not involved in maintaining the polymorphism in X. helleri. We suggest that explanations need to be sought for the evolution of melanophore diversity in Xiphophorus that are pertinent to each melanin pattern polymorphism or groups of similar polymorphisms.
剑尾鱼属鱼类中，个体、种群和物种间黑色素模式的差异很常见。在多变的剑尾鱼（Xiphophorus variatus）中，代谢率的变化与黑色素沉着有关，而且颜色变体似乎是适应特定环境条件的生理特化类型。本研究调查了绿剑尾鱼（Xiphophorus helleri）中的黑色素多态性是否同样与代谢率的变化有关。我们在静态呼吸仪中测量了成年雄性和幼年绿剑尾鱼的代谢率，以耗氧率表示。两组中斑点形态和无斑点形态的耗氧率均无显著差异，这表明与剑尾鱼不同，代谢率的选择并不参与维持绿剑尾鱼的多态性。我们建议，需要寻找与剑尾鱼中黑素细胞多样性进化相关的解释，这些解释应与每种黑色素模式多态性或相似多态性组相关。
