Department of Animal Ecology and Physiology, Radboud University, Nijmegen, The Netherlands.
Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania.
J Anim Ecol. 2019 May;88(5):768-779. doi: 10.1111/1365-2656.12966. Epub 2019 Mar 18.
Changes in population dynamics due to interacting evolutionary and ecological processes are the direct result of responses in vital rates, that is stage-specific growth, survival and fecundity. Quantifying through which vital rates population fitness is affected, instead of focusing on population trends only, can give a more mechanistic understanding of eco-evolutionary dynamics. The aim of this study was to estimate the underlying demographic rates of aphid (Myzus persicae) populations. We analysed unpublished stage-structure population dynamics data of a field experiment with caged and uncaged populations in which rapid evolutionary dynamics were observed, as well as unpublished results from an individual life table experiment performed in a glasshouse. Using data on changes in population abundance and stage distributions over time, we estimated transition matrices with inverse modelling techniques, in a Bayesian framework. The model used to fit across all experimental treatments included density as well as clone-specific caging effects. We additionally used individual life table data to inform the model on survival, growth and reproduction. Results suggest that clones varied considerably in vital rates, and imply trade-offs between reproduction and survival. Responses to densities also varied between clones. Negative density dependence was found in growth and reproduction, and the presence of predators and competitors further decreased these two vital rates, while survival estimates increased. Under uncaged conditions, population growth rates of the evolving populations were increased compared to the expectation based on the pure clones. Our inverse modelling approach revealed how much vital rates contributed to the eco-evolutionary dynamics. The decomposition analysis showed that variation in population growth rates in the evolving populations was to a large extent shaped by plant size. Yet, it also revealed an impact of evolutionary changes in clonal composition. Finally, we discuss that inverse modelling is a complex problem, as multiple combinations of individual rates can result in the same dynamics. We discuss assumptions and limitations, as well as opportunities, of this approach.
由于相互作用的进化和生态过程引起的种群动态变化是生命率变化的直接结果，即特定阶段的生长、存活和繁殖。通过量化哪些生命率影响种群适应性，而不仅仅关注种群趋势，可以更深入地了解生态进化动态的机制。本研究的目的是估计蚜虫（Myzus persicae）种群的潜在人口统计学率。我们分析了未发表的带有笼养和未笼养种群的田间实验的阶段结构种群动态数据，在该实验中观察到了快速的进化动态，以及在温室中进行的个体生命表实验的未发表结果。使用随时间变化的种群丰度和阶段分布数据，我们使用逆建模技术在贝叶斯框架中估计了转移矩阵。适用于所有实验处理的模型包括密度以及克隆特异性笼养效应。我们还使用个体生命表数据为模型提供有关存活率、生长和繁殖的信息。结果表明，克隆在生命率方面存在很大差异，并且在繁殖和存活率之间存在权衡。对密度的反应也因克隆而异。发现生长和繁殖存在负密度依赖性，捕食者和竞争者的存在进一步降低了这两个生命率，而存活率估计值增加。在未笼养条件下，与纯克隆相比，进化种群的种群增长率增加。我们的逆建模方法揭示了生命率对生态进化动态的贡献程度。分解分析表明，进化种群中种群增长率的变化在很大程度上由植物大小决定。然而，它还揭示了克隆组成的进化变化的影响。最后，我们讨论了逆建模是一个复杂的问题，因为个体率的多种组合可以导致相同的动态。我们讨论了这种方法的假设、局限性以及机会。
