The Paradox of Coexistence: The Evolution of Ontogenetic Interactions

当两个物种对另一个物种产生负面影响时，它们是如何共存的？ 当一个新物种入侵一个栖息地时，我们如何预测它是否会与本地物种共存，是否会导致一个或多个物种灭绝，或者是否会被本地物种灭绝？这项研究将探讨共存是否是物种相互作用的进化属性。如果在第一次接触时不能共存的物种能够在彼此的特征上作为自然选择的代理人，使它们能够迅速进化以共存，那么这种情况就会发生。 了解这种进化何时以及如何发生，可以对我们预测入侵、物种重新放养和栖息地改变对生物多样性的影响的能力产生深远的影响。这项研究将吸引本科生研究人员，以及与外展网站的公众参与。这项研究的重点是最具挑战性的物种相互作用之一，当两个物种的成年人相互竞争食物时，每个人都会捕食另一个物种的幼仔。 这项研究将探讨如何哈特的鳉鱼和特立尼达孔雀鱼，以这种方式相互作用，以某种方式共存于较高海拔的溪流在特立尼达。 通常情况下，当孔雀鱼入侵仅容纳鳉鱼的位置时，孔雀鱼会遇到鳉鱼。 这项研究利用了这样一个事实，即可以在与孔雀鱼和从未遇到过孔雀鱼的种群共存的鳉鱼种群之间进行比较，沿着的是没有入侵鳉鱼的位置的孔雀鱼种群之间的比较，在最近的实验中已经引入这些位置的种群，以及与鳉鱼共存数十年的种群。 这项工作包括在人工溪流中混合和匹配这些种群的实验，以研究每个物种的适应性如何取决于其自身遗传背景和其他物种的遗传背景的组合。 它还包括在自然水池中进行实验，去除一个物种以测量其对另一个物种的净影响。 研究人员还将记录实验引入中孔雀鱼和鳉鱼的命运，以评估实际发生的进化程度。 此外，还将进行实验室实验，将物种内部和物种之间不同体型的个体配对，以了解竞争和捕食如何取决于相互作用个体的相对体型。 最后，该研究将综合这些结果与计算模型，描述生态和进化轨迹，这可以用来作为工具，了解在各种情况下的生物多样性的命运。

How do two species coexist when each has a negative impact on the other? When a new species invades a habitat, how can we predict whether it will coexist with the native species, drive one or more of them extinct, or be driven to extinction itself by the natives? This research will investigate whether coexistence is an evolved property of species interactions. This will happen if species that could not coexist on first contact can act as agents of natural selection on each other's features in a way that enables them to evolve rapidly to coexist. Understanding when and how this evolution occurs can have a profound effect on our ability to predict the results of invasions, species re-stocking, and habitat alteration on biodiversity. This research will engage undergraduate researchers, as well as engaging the public with an outreach website.This research focuses on one of the most challenging of species interactions, which occurs when the adults of two species compete with each other for food but each preys on juveniles of the other. This research will examine how Hart's killifish and Trinidadian guppies, which interact in this manner, somehow coexist in higher elevation streams in Trinidad. Typically, guppies encounter killifish when guppies invade locations that have held only killifish. This research exploits the fact that comparisons can be made among killifish populations that coexist with guppies and populations that have never encountered guppies, along with comparisons between guppy populations that have not invaded killifish-only locations, populations that have been introduced into those locations in recent experiments, and populations that have coexisted with killifish for decades. The work includes experiments in artificial streams that mix and match these populations to examine how fitness of each species depends on the combinations of its own genetic background and that of the other species. It also includes experiments in natural pools that remove one species to measure its net effect on the other. The researchers will also be documenting the fates of guppies and killifish in experimental introductions to assess how much evolution is actually occurring. There will also be laboratory experiments that pair individuals of different body sizes within and among species to understand how competition and predation depend on relative body sizes of interacting individuals. Finally, the research will synthesize these results with computational models that describe the ecological and evolutionary trajectories, which can be used as tools for understanding the fate of biodiversity in a variety of contexts.