Effects of Rapid Consumer Evolution on Community Dynamics: Predictions and Tests in a (nearly) Natural Food Web

生物种群具有极强的适应环境变化的能力。适应性进化增加了具有特定特征(基因)的个体的相对丰度，这些基因使他们比那些具有不同特征的个体更好地生存和繁殖。生物体？S的基因决定了它与环境的相互作用，包括与其他物种的相互作用。种群中存在的基因类型的多样性，以及环境变化的程度，不仅决定了进化发生的速度有多快，而且还决定了随着环境的变化，种群的数量增加或减少的方式。数学理论和简单的实验室捕食者-猎物实验表明，种群进化的能力显著影响种群数量是否变化以及变化的速度有多快。在进化和不进化的情况下，捕食者和猎物丰度的周期看起来非常不同。这个项目测试这些进化的捕食者-猎物循环对于理解在更自然的条件下物种丰度的变化是否重要，在更自然的条件下，天气每天都在变化，季节来来去去，它们植根于一个由许多物种组成的群落中。这项研究将使用重复的实验池塘来记录淡水浮游植物丰度随时间的变化，这是由以浮游植物为食的动物水蚤丰度的增加和减少所驱动的。这项实验将操纵水蚤种群的遗传变异量，以改变它们的进化能力，并确定这如何影响浮游植物丰度和水体透明度的季节性变化。将开发基因组学方法来跟踪水蚤种群的进化变化。该项目在淡水湖管理中具有实用价值，因为水蚤进化的能力可能决定水蚤何时以及如何调节水的清晰度，这是湖泊环境质量的一个主要特征。该项目将为博士后学者以及研究生和本科生提供研究培训和职业指导。此外，高中生还将通过暑期研究体验参与进行实地实验。

Populations of organisms have a remarkable capacity to adapt to environmental change. Adaptive evolution increases the relative abundance of individuals with genes for particular traits (genotype) that allow them to survive and reproduce better than those with different traits. An organism?s genotype determines how it interacts with its environment, including with other species. The variety of genotypes present in a population, and how much the environment changes, dictate not only how fast evolution will occur, but also how that population increases or decreases in abundance as the environment changes. Mathematical theory and simple laboratory predator-prey experiments demonstrate that the ability of a population to evolve markedly affects whether, and how quickly, it changes in abundance. The cycles of predator and prey abundance look very different with and without evolution. This project tests whether these evolutionary predator-prey cycles are important in understanding changes in species abundance in more natural conditions where weather varies daily, seasons come and go, and they are imbedded in a community of many species. The research will use replicate experimental ponds to document changes over time of freshwater phytoplankton abundances driven by the increases and decreases in the abundance of Daphnia, an animal that feeds on phytoplankton. The experiment will manipulate the amount of genetic variation in the Daphnia populations in order to change their capacity to evolve, and to determine how that affects seasonal changes in phytoplankton abundance and water clarity. Genomic methods will be developed to track evolutionary changes in the Daphnia populations. This project has practical value in the management of freshwater lakes since the capacity for Daphnia to evolve may determine when and how Daphnia regulates water clarity, a major feature of environmental quality in lakes. This project will provide research training and career mentoring for a postdoctoral scholar, and for graduate and undergraduate students. In addition, high school students will participate in conducting the field experiments through summer research experiences.