Dissertation Research - Cascading Speciation in a Parasitoid Wasp

该项目将探索一种涉及苹果蝇(Rhagoltis Pomonella)和一种捕食果蝇幼虫的寄生蜂(Diachasma Alleum)的“级联”物种形成事件。这两种生物的种群都从它们的祖先宿主山楂树转移到了引进的欧洲苹果上。过去的研究表明，这种转变已经导致了苹果和山楂相关的波蒙氏菌小种的形成，每个小种都适应了它们各自的宿主。人们认为，这些小种是形成不同物种的第一步。这项研究将通过黄蜂生活史、行为和遗传的差异来寻找异地黄蜂中平行小种形成的证据。这项研究的更广泛的意义在于，它将有助于形成对生物多样性潜在过程的更完整的理解。植食性(以植物为食)和寄生昆虫是地球上种类最多的生物。生物学的统一目标之一是揭开这种壮观多样性的来源。研究如此紧密的植物和昆虫生态网络的进化动力学，应该能弄清楚自然选择创造新物种的一些过程。此外，这项工作将引起进化生物学家的普遍兴趣，因为它涉及到在没有地理隔离的情况下的物种形成，对于这一事件，几乎没有确凿的例子。

This project will explore a "cascading" speciation event involving the apple maggot fly (Rhagoletis pomonella) and a parasitoid wasp (Diachasma alloeum) that hunts and consumes the fly's larvae. Populations of both of these organisms have made a shift from their ancestral host, the hawthorn tree, to introduced European apples. Past work has shown that this shift has resulted in the formation of apple- and hawthorn-associated "races" of R. pomonella, each adapted to their respective hosts. It is believed that these races are a first step towards formation of distinct species. This project will look for evidence of a parallel race formation in D. alloeum through differences in wasp life history, behavior and genetics.The broader significance of this research is that it will help to form a more complete understanding of the processes underlying biodiversity. Phytophagous (plant-feeding) and parasitic insects are the most diverse organisms on Earth. One of the unifying goals in biology involves uncovering the sources of this spectacular diversity. Studying the evolutionary dynamics of such a tight ecological network of plants and insects should make clear some of the processes through which natural selection acts to create new species. Furthermore, this work will be of general interest to evolutionary biologists because it involves speciation in the absence of geographic isolation, an event for which few conclusive examples exist.