Dissertation Research: Effects of a History of EnvironmentalHeterogeneity on Rates of Adaptation to a Novel Environment

环境异质性可能会影响与新环境中的表现相关的性状的加性遗传方差的量。这可能影响具有特定历史的人口跟踪环境变化和适应新环境的潜力。拟议的实验将测量环境异质性对性状选择的影响，通过正在变化的环境的特征。在这三个阶段的计划中，将使用双翅目潜叶蝇Liriomyza trifolii作为模型系统。在第一阶段，采用L.将建立trifolii。在第2阶段，基础种群的重复亚群将经受均匀或异质宿主植物条件20代。然后，将测量每个重复亚群中与新植物上的适合度相关的性状的遗传方差和协方差。在第3阶段，将在新植物上启动来自每个处理亚群的重复选择系。将测量所有品系对新植物的选择反应，并在环境异质性处理之间进行比较，以测试种群历史对进化动力学的影响。在对新植物进行10代自然选择后，将重新测量适合度分量中的遗传方差和协方差。将计算新植物在选择期间对这些群体施加的净选择。将测试对具有不同环境异质性历史的种群在面对新环境时的进化动力学的定性预测。

Environmental heterogeneity may influence the amount of additive genetic variance in traits relevant to performance in a novel environment. This can affect the potential of a population with a given history to track environmental change and to adapt to a new environment. The proposed experiments will measure the effect of environmental heterogeneity on traits under selection by the feature of the environment that is being varied. Liriomyza trifolii, a dipteran leafminer, will be used as a model system in this three phase program. In phase 1, a genetically variable base population of L. trifolii will be established. In phase 2, replicate subpopulations of the base population will be subjected to either uniform or heterogeneous host plant conditions for 20 generations. Then the genetic variances and covariances in each replicate subpopulation for characters related to fitness on a novel plant will be measured. In phase 3, replicate selection lines from each treatment subpopulation will be initiated on the novel plant. Responses to selection on the novel plant will be measured for all lines and compared among the environmental heterogeneity treatments in order to test the effects of population history on evolutionary dynamics. After 10 generations of natural selection on the novel plant, genetic variances and covariances in fitness components will be re- measured. Net selection imposed by the novel plant on these populations during the selection period will be calculated. Qualitative predictions about the evolutionary dynamics of populations with different histories of environmental heterogeneity when faced with a new environment will be tested.