RAPID: Testing the role of spatial sorting as an important driver of rapid adaptive divergence

生物体的特征，提高他们的传播速度可以在人口迅速殖民新的栖息地青睐。如果分散的个体与周围种群中相似的、高度移动的个体交配，情况尤其如此。这个过程被称为“空间分类”，产生的后代也是快速扩散者，而不管这些基因如何影响种群在新栖息地的适应性。该项目将进行第一次大规模的实地测试空间排序，以产生快速进化，使用红肩无患子虫（Jadera haematoloma）的种群，在过去的60年里，它已经从本地到非本地的食用植物扩展和适应。飓风哈维罕见的偶发性洪水提供了一个独特的机会，通过导致一些种群灭绝，而另一些种群仍然完好无损，来逆转肥皂虫种群的（短）进化时钟。这项研究的结果可用于了解入侵物种如何殖民新的栖息地，并最终取代本地种群。该项目还将支持关于殖民人口进化的外联公共教育。一个基本的问题是，J.血肿种群如何进化得如此之快？这个问题的答案可能来自最初殖民者的特征。无患子蝽表现出飞行多态性，其中有一个长翅膀的形式，这是一个较大的身体主要的传播者，和一个短翅膀的形式，不飞，身体较小。长翅变种也有更大的口器，这对新的非本地宿主植物是有益的。该项目将测试所观察到的从本地宿主植物（其中较小的口器是有利的）到非本地宿主植物（其中较大的口器是有利的）的快速适应是否是通过空间分选而不是通过来自常设表型变异的自然选择来促进的。为此，将进行实地观察研究、操纵移植实验、扩散表型遗传基础的实验室测试以及减少种群内遗传变异的遗传测试。

Traits of organisms that enhance their rates of dispersal can be favored in populations that are rapidly colonizing new habitats. This is especially true if the dispersing individuals mate with similar, highly mobile individuals from surrounding populations. This process, termed "spatial sorting", generates offspring that are also rapid dispersers, regardless of how those genes affect the population's fitness in the new habitat. This project will perform the first large-scale field tests of spatial sorting in generating rapid evolution using populations of the red-shouldered soapberry bug (Jadera haematoloma), which has expanded and adapted from native to non-native food plants in the last 60 years. The rare episodic flooding from Hurricane Harvey has provided a unique opportunity to roll back the (short) evolutionary clock on soapberry bug populations by causing some populations to go extinct while others are still intact. Results from this study can be applied to understanding how invasive species colonize new habitats and ultimately displace native populations. This project also will support outreach public education on evolution in colonizing populations. One fundamental question is how could J. haematoloma populations evolve so quickly? The answer to this question may emerge from features of the initial colonizers. Soapberry bugs exhibits a flight polymorphism, where there is a long-winged form that is the main disperser with a larger body, and a short-winged form that does not fly well with a smaller body. Long-wing morphs also have larger mouthparts that are beneficial on the new non-native host plant. This project will test whether the observed rapid adaptation from a native host plant, where smaller mouthparts are favored, to a non-native host plant, where larger mouthparts are favored, was promoted by spatial sorting as opposed to natural selection from standing phenotypic variation. To do this, field observational studies, a manipulative transplant experiment, lab tests of the genetic basis of dispersal phenotypes, as well as genetic tests for reductions in genetic variation within populations will be performed.