Department of Zoology, University of Oklahoma, Norman, OK, USA.
J Evol Biol. 2011 Mar;24(3):596-606. doi: 10.1111/j.1420-9101.2010.02194.x. Epub 2010 Dec 16.
Chronic environmental stress is known to induce evolutionary change. Here, we assessed male life-history trait divergence in the neotropical fish Poecilia mexicana from a system that has been described to undergo incipient ecological speciation in adjacent, but reproductively isolated toxic/nontoxic and surface/cave habitats. Examining both field-caught and common garden-reared specimens, we investigated the extent of differentiation and plasticity of life-history strategies employed by male P. mexicana. We found strong site-specific life-history divergence in traits such as fat content, standard length and gonadosomatic index. The majority of site-specific life-history differences were also expressed under common garden-rearing conditions. We propose that apparent conservatism of male life histories is the result of other (genetically based) changes in physiology and behaviour between populations. Together with the results from previous studies, this is strong evidence for local adaptation as a result of ecologically based divergent selection.
慢性环境压力已知会诱导进化改变。在这里，我们评估了来自一个系统的新热带鱼类墨西哥脂鲤的雄性生活史特征的分歧，该系统被描述为在相邻但具有生殖隔离的有毒/无毒和地表/洞穴栖息地中经历初生的生态物种形成。通过检查野外捕获和普通花园养殖的标本，我们研究了雄性 P. mexicana 所采用的生活史策略的分化和可塑性程度。我们发现，脂肪含量、标准长度和性腺体指数等特征存在强烈的特定地点的生活史分歧。大多数特定地点的生活史差异在普通花园养殖条件下也得到了表达。我们提出，雄性生活史的明显保守性是由于种群之间的其他（基于遗传的）生理和行为变化所致。结合之前研究的结果，这有力地证明了生态基础的分歧选择导致了局部适应。
