Siepielski Adam M, Nemirov Alex, Cattivera Matthew, Nickerson Avery
Am Nat. 2016 Apr;187(4):447-56. doi: 10.1086/685295. Epub 2016 Feb 22.
Determining how adaptive evolution can be coupled to ecological processes is key for developing a more integrative understanding of the demographic factors that regulate populations. Intraspecific competition is an especially important ecological process because it generates negative density dependence in demographic rates. Although ecological factors are most often investigated to determine the strength of density dependence, evolutionary processes such as local adaptation could also feed back to shape variation in the strength of density dependence among populations. Using an experimental approach with damselflies, a predaceous aquatic insect, we find evidence that both density-dependent intraspecific competition and local adaptation can reduce per capita growth rates. In some cases, the effects of local adaptation on reducing per capita growth rates exceeded the ecological competitive effects of a doubling of density. However, we also found that these ecological and evolutionary properties of populations are coupled, and we offer two interpretations of the causes underlying this pattern: (1) the strength of density-dependent competition depends on the extent of local adaptation, or (2) the extent of local adaptation is shaped by the strength of density-dependent competition. Regardless of the underlying causal pathway, these results show how eco-evolutionary dynamics can affect a key demographic process regulating populations.
确定适应性进化如何与生态过程相联系，是更全面理解调节种群的人口统计学因素的关键。种内竞争是一个尤为重要的生态过程，因为它会在人口统计学比率中产生负密度依赖。虽然生态因素通常是为了确定密度依赖的强度而进行研究，但诸如局部适应等进化过程也可能会反馈回来，从而塑造种群间密度依赖强度的变化。通过对豆娘（一种捕食性水生昆虫）采用实验方法，我们发现有证据表明，密度依赖的种内竞争和局部适应都会降低人均增长率。在某些情况下，局部适应对降低人均增长率的影响超过了密度翻倍所产生的生态竞争效应。然而，我们还发现种群的这些生态和进化特性是相互联系的，并且我们对这种模式背后的原因给出了两种解释：（1）密度依赖竞争的强度取决于局部适应的程度，或者（2）局部适应的程度由密度依赖竞争的强度所塑造。无论潜在的因果路径如何，这些结果都表明了生态进化动态如何影响调节种群的关键人口统计学过程。
