DISSERTATION RESEARCH: Predation and Disease: Examining Patterns of Predator Diversity and Parasite Infection in Nature

宿主-寄生虫的相互作用通常是在复杂的群落中进行的，在这些群落中，寄生虫的传播不仅依赖于宿主物种，而且依赖于捕食者等非宿主物种。最近的研究集中在捕食者通过控制宿主和媒介的种群密度来限制宿主暴露于其病原体的能力上。捕食者降低疾病风险的另一种机制是直接吞噬寄生虫自由生活的感染阶段。初步证据表明，这种机制可能在水生生态系统中很常见，在水生生态系统中，各种捕食者物种消耗自由生活阶段的寄生虫，包括吸虫等大型寄生虫。该项目的中心目标是确定捕食者的组合如何影响自然界中两栖动物的寄生虫感染，以及捕食者物种的消失是否会导致疾病动态的重大变化。这项研究扩展了最初的实验室发现，通过对水生多样性的广泛调查和在景观水平上对宿主感染和疾病的精确检查，在实地测试了对寄生虫捕食的假设。这项研究结合了数学建模、实验室实验和实地调查，将自然模式的观察与功能机制联系起来。由于吸虫是人类、家畜和野生动物的常见病原体，这项研究将促进对生物多样性的丧失，特别是捕食者的丧失如何可能是最近一些疾病出现的一个因素的理解。传播模型的发展、实地水生捕食者群落结构的评价以及疾病风险的计算将对野生动物和人类疾病的管理具有实际应用价值。该项目将为当地一所小学提供广泛的课外活动，该小学有许多学生来自科学领域代表性不足的群体，并通过博尔德县4-H开展的环境科学项目。本科生和高中生将参与研究并接受科学职业指导。

While often studied in isolation, host-parasite interactions are typically embedded within complex communities in which parasite transmission is dependent not just on the host species, but non-host species such as predators. Recent research has focused on the ability of predators to limit the exposure of hosts to their pathogens by controlling population density of hosts and vectors. An additional mechanism by which predators could lower the risk of disease is by directly consuming parasite free-living infective stages. Preliminary evidence suggests that this mechanism may be common in aquatic ecosystems where various predator species consume free-living stages of parasites, including macroparasites such as trematodes. The central goal of this project is to determine how assemblages of predators affect parasitic infection of amphibians in nature, and whether loss of predator species would cause significant changes to disease dynamics. This research extends initial laboratory findings by testing hypotheses of predation on parasites in the field through extensive surveys of aquatic diversity and precise examination of host infection and disease on the landscape level. This research combines mathematical modeling, laboratory experiments, and field surveys linking observations of natural patterns to functional mechanisms. Since trematodes are common pathogens of humans, domestic animals, and wildlife this study will advance understanding of how loss of biodiversity in general and predators in particular may be a factor in the recent emergence of some diseases. Development of the transmission models, evaluations of aquatic predator community structure in the field, and calculations of disease risk will be of practical application to management of wildlife and human diseases. This project will provide extensive outreach through after school programs for a local elementary school having many students from groups underrepresented in science, and through environmental science programs conducted by Boulder County 4-H. Undergraduate and high school students will be involved in the research and receive mentoring on science careers.