Dissertation Research: Effect of phoretic dispersal on the structure of parasite populations

通过比较以不同方式传播的寄生虫种群遗传结构的差异，本研究将确定传播的增加和减少如何影响这种结构。了解种群结构的方式和原因是进化生物学家的主要目标，因为由此产生的种群遗传结构影响着当地适应、物种形成和灭绝的速度。这项研究将研究生活在鸽子羽毛上的虱子的种群遗传结构。由于地理或生态因素影响到两个个体交配的机会，自然种群通常被细分，或基因结构。影响种群遗传结构的一个主要因素是分散，即个体从一个地方迁移到另一个地方。当个体分散到新的种群时，它们会与新种群中的个体交配，从而降低种群的遗传结构。我们对扩散如何影响这种结构的大小知之甚少。宿主-寄生虫系统为研究不同的传播模式如何影响种群遗传结构提供了高度可处理的系统。这项研究将通过检查位于同一宿主个体上的不同寄生虫物种的种群遗传结构来做到这一点。此外，这项研究将产生一项针对中学生的探究式活动，“搭便车者城市指南：虱子的教训”，并将有助于研究生和本科生的培训。在这项研究中，研究人员将使用鸽子-虱子，宿主-寄生虫系统来研究两种寄生羽虱（目：Phthiraptera）之间种群遗传结构的差异，这两种寄生羽虱的传播能力不同。该研究将调查垂直传播和水平传播在岩鸽（Columba livia）身上发生的翼虱和体虱种群结构中的作用。虽然这些虱子在生态学上非常相似，但翼虱可以利用苍蝇进行传播，而体虱则不行。尽管假体普遍存在，但这种传播机制对这些生物种群结构的影响尚不清楚。研究人员将使用一种嵌套抽样设计，从世界不同地区的不同宿主个体、不同种群中收集虱子。他们将在有苍蝇的区域取样，在没有苍蝇和不能进行电泳的区域取样。他们将使用微卫星数据来确定垂直和水平传播在构成虱子种群中的相对作用。

By comparing differences in the population genetic structure of parasites that disperse in different ways, this study will determine how increases and decreases in dispersal influence that structure. Understanding how and why populations are structured is a major goal of evolutionary biologists because the resulting population genetic structure affects rates of local adaptation, speciation and extinction. This study will examine the population genetic structure of lice that live on the feathers of pigeons. Natural populations are typically subdivided, or genetically structured, because geographic or ecological factors influence the chance that two individuals will mate. One major factor that influences population genetic structure is dispersal, the movement of individuals from one place to another. When individuals disperse to new populations, they mate with individuals in the new population reducing population genetic structure. We know little about how dispersal affects the magnitude of this structure. Host-parasite systems offer highly tractable systems with which to study how different modes of dispersal influence population genetic structure. This study will do so by examining population genetic structure of different parasite species that are located on the same host individuals. In addition, this study will produce an inquiry-based activity aimed at middle-school students, "Hitchhikers guide to the city: Lessons from lice," and will contribute to the training of graduate and undergraduate students.In this study, researchers will use a pigeon-louse, host-parasite system to investigate how population genetic structure differs between two species of parasitic feather lice (Order: Phthiraptera) that differ in their ability to disperse. The study will investigate the role of vertical dispersal and horizontal dispersal in structuring the populations of wing lice and body lice that occur on Rock Pigeons (Columba livia). Although these lice are ecologically very similar, wing lice can disperse phoretically using flies, whereas body lice do not. Despite the pervasiveness of phoresy, the affect that this dispersal mechanism has on the population structure of these organisms is unknown. Researchers will use a nested sampling design to collect lice from different host individuals, in different flocks, in different regions of the world. They will sample in regions where flies are present, and where flies are not present and phoresis cannot occur. They will use microsatellite data to determine the relative role of vertical and horizontal-phoretic dispersal in structuring louse populations.