Population genetics and independently replicated evolution of predator-associated burst speed ecophenotypy in mosquitofish

Many species show replicated ecophenotypy due to recurring patterns of natural selection. Based on the presence or absence of pursuit predators, at least 17 species of fish repeatedly differentiated in body shape in a manner that increases burst swimming speed and the likelihood of predator escape. The predator-associated burst speed (PABS) ecophenotype is characterized by a small head and trunk and enlarged caudal region. Mechanisms promoting replicated phenotype-environment association include selection (without evolution), a single instance of adaptive evolution followed by biased habitat occupation, repeated instances of local adaptation, or adaptive phenotypic plasticity. Common garden rearing of mosquitofish, Gambusia affinis, demonstrated a likely heritable basis for PABS phenotypy, but it is unknown whether populations are otherwise genetically distinct or whether replicated ecophenotypy represents a single or replicated instances of adaptation. To genetically characterize the p...

许多物种因自然选择的重复模式而表现出复制性生态表型。基于追捕型捕食者的存在与否，至少17种鱼类的体型重复分化，该分化方式可提升突发游泳速度及逃脱捕食者的概率。与捕食者相关的突发速度（predator-associated burst speed, PABS）生态表型的特征为头部和躯干较小、尾部区域增大。促进复制性表型-环境关联的机制包括（无进化的）选择、适应性进化单次发生后偏向性栖息地占据、局部适应的重复发生或适应性表型可塑性。对食蚊鱼（Gambusia affinis）开展共同花园饲养实验表明，PABS表型可能具有可遗传基础，但种群在其他方面是否存在遗传差异、复制性生态表型代表单次还是重复的适应事件，目前仍不明确。为从遗传层面表征p...