Variation in life-history traits among Daphnia and its relationship to species-level responses to phosphorus limitation

Currently organisms are experiencing changes in their environment at an unprecedented rate. Therefore the study of the contributions to and responses in traits linked to fitness is crucial, as they have direct consequences on a population’s success in persisting under such change. Daphnia is used as a model organism as the genus contains keystone primary consumers in aquatic food webs. A life-history table experiment (LHTE) using four species of Daphnia was conducted to compare variation in life-history traits among species across two different environmental conditions (high and low phosphorous availability). Results indicate that the food quality environment had the most impact on life-history traits, while genetic contributions to traits were higher at the species-level than clonal-level. Higher trait variation and species-level responses to P-limitation was more evident in reproductive traits, while growth traits were found to be less affected by food quality and had less variation....

当前，生物类群正以前所未有的速率经历栖息环境的剧烈变化。因此，探究与适合度（fitness）相关的性状的调控贡献与响应机制至关重要——此类性状直接决定了种群在这类环境变化下的存续成功率。水蚤属（Daphnia）物种是水生食物网中的关键初级消费者，常被用作模式生物。本研究选取4种水蚤开展生命表实验（life-history table experiment, LHTE），旨在对比两种不同环境条件（高、低磷有效性）下各物种间生活史性状的变异差异。研究结果显示，食物质量环境对生活史性状的影响最为显著；且性状的遗传贡献在物种水平上显著高于克隆水平。繁殖性状表现出更高的性状变异程度，且物种对磷限制的响应更为显著；而生长性状受食物质量的影响较弱，其变异程度也相对更低……