Shape variation in the least killifish: ecological associations of phenotypic variation and the effects of a common garden

Studies of the adaptive significance of variation among conspecific populations often focus on a single ecological factor. However, habitats rarely differ in only a single ecological factor, creating a challenge for identifying the relative importance of the various ecological factors that might be maintaining local adaptation. Here we investigate the ecological factors associated with male body shape variation among nine populations of the poeciliid fish, Heterandria formosa, from three distinct habitats and combine those results with a laboratory study of three of those populations to assess the contributions of genetic and environmental influences to shape variation. Field-collected animals varied principally in three ways: the orientation of the gonopodium, the intromittent organ; the degree of body depth and streamlining; and the shape of the tail musculature. Fish collected in the spring season were larger and had a more anteriorly positioned gonopodium than fish collected in autu...针对同种种群间变异的适应性意义开展的研究，通常仅聚焦于单一生态因子。然而自然生境的差异极少仅局限于单一生态因子，这为甄别可能维持局地适应的各类生态因子的相对重要性带来了挑战。本研究针对源自3种不同生境的9个种群的花鳉科鱼类（poeciliid fish）美丽异鳉（Heterandria formosa）的雄性体型变异相关生态因子展开调查，并结合针对其中3个种群的实验室研究，以评估遗传与环境因素对体型变异的贡献。野外采集的样本主要存在三方面差异：其一为交尾器（gonopodium，雄性插入器官）的朝向；其二为体高与流线化程度；其三为尾部肌肉的形态。春季采集的个体体型更大，且交尾器位置较秋季采集的个体更靠前……