IRFP: Exploring the Impacts of Human Land Use on Parasite Transmission Dynamics in a Dung Beetle-Fecal Helminth Model System

国际研究奖学金计划使美国科学家和工程师能够在国外进行9到24个月的研究。该项目的奖项提供了联合研究的机会，并提供了使用国外独特或互补的设施、专业知识和实验条件的机会。这一奖项将支持伊丽莎白·尼科尔斯博士与英国兰开斯特大学肯尼斯·威尔逊教授合作的为期24个月的研究奖学金。寄生和自由生活的类群之间的生物相互作用是一系列生态系统过程的基础，包括调节群落中物种之间的寄生虫病传播。具有复杂生命周期的寄生虫(例如寄生虫)对全球热带地区的人和牲畜造成巨大的适应能力和经济代价。然而，环境变化如何影响涉及寄生虫传播的生物相互作用仍然知之甚少。拟议的项目旨在开发一种新的粪甲虫-粪便蠕虫模型系统，通过影响自由生活物种和寄生虫之间的相互作用，梳理土地利用变化影响寄生虫病传播的机制。由于许多甲虫物种广泛使用不同哺乳动物物种的粪便，热带农业景观中的甲虫群落通常与两种不同传播策略的粪便蠕虫(寄生蠕虫)相互作用：野生和家养食草动物的粪便-口腔蠕虫，以及野生和家养食肉动物的滋养传播蠕虫(当它们捕食成年甲虫时)。初步数据表明，甲虫粪便的处理通常会降低粪便-口腔蠕虫的传播成功率，但会增加营养传播蠕虫的传播，而甲虫通常充当中间宿主。这些截然不同的结果表明，改变甲虫群落多样性的土地利用变化可能同时抑制和维持或放大不同哺乳动物宿主物种之间的疾病传播。此外，这些影响的大小和方向可以通过一小组屎甲虫物种的特征来预测。该项目结合野外、实验和模拟方法，研究了寄生虫群落对寄生虫传播的调控和土地利用变化对传播动力学的影响之间的机制关系。在基础水平上，该研究将(1)提高我们对传播动力学的潜在机制及其对土地利用变化的响应的理解，(2)有助于开发一种新的模型系统，该模型系统可以在现有的单一微寄生虫传播模型的基础上扩展，以评估多种复杂的生活史寄生虫物种如何响应自由生活物种多样性的变化。蠕虫(寄生蠕虫)对热带农业景观的经济和健康影响是巨大的。在应用层面上，这项工作将提供有用的信息，说明农业区的环境变化如何影响那些与生态系统服务结果密切相关的物种相互作用，例如减少疾病传播。除了这些好处外，这项研究还将有助于发展国际和平研究所与兰开斯特大学、英国兰开斯特大学、拉夫拉斯联邦大学、巴西拉夫拉斯大学、S大学、巴西S圣保罗大学、美国纽约巴纳德学院和美国纽约自然历史博物馆的研究小组之间的新的国际合作。

The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twenty-four-month research fellowship by Dr. Elizabeth Nichols to work with Prof. Kenneth Wilson at Lancaster University, Lancaster UK. Biotic interactions between parasitic and free-living taxa are fundamental to a range of ecosystem processes, including the mediation of parasitic disease transmission between species in a community. Parasites with complex life-cycles (e.g. helminthes (parasitic worms)) exert enormous fitness and economic costs on humans and livestock across the global tropics. However how environmental change affects the biotic interactions involved in parasite transmission remains poorly understood. The proposed project seeks to develop a novel dung beetle - fecal helminth model system to tease apart the mechanisms by which land-use change influences parasitic disease transmission, by impacting interactions between free-living species and parasitic helminths. As many dung beetles species broadly use the feces of different mammal species, beetle communities in tropical agricultural landscapes commonly interact with fecal helminths (parasitic worms) of two distinct transmission strategies: the fecal-oral helminths of wild and domestic herbivores, and the trophically transmitted helminths of wild and domestic carnivores (when they eat the adult beetles). Preliminary data indicates that dung beetle feces processing often decreases the rate of successful transmission for fecal-oral helminths, yet increases the transmission of trophic transmissions helminths, for which beetles commonly act as intermediate hosts. These strikingly different outcomes suggest that land-use changes that alter dung beetle community diversity may simultaneously suppress and maintain or amplify disease transmission across different mammal host species. In addition, the magnitude and direction of these effects may be predicted by a small set of dung beetle species' traits. This project combines field, experimental and modeling approaches to characterize the mechanistic relationships between dung beetle community regulation of parasite transmission, and the impacts of land-use change on transmission dynamics.At a basic level, the research will (1) enhance our understanding of the mechanisms underlying transmission dynamics and their response to land-use change, and (2) contribute to the development of a novel model system that can expands upon extant single-microparasite transmission models to assess how multiple complex life-cycle parasite species respond changes in free-living species diversity. The economic and health impacts of helminths (parasitic worms) in tropical agricultural landscapes are tremendous. At an applied level, this work will provide useful information on how environmental change in agricultural areas influences those species interactions tightly linked to ecosystem service outcomes, such as reduced disease transmission. In addition to these benefits, this research will help develop new international collaboration between the PI and research groups at Lancaster University, Lancaster UK, the Federal University of Lavras, Lavras Brazil, the University of São Paulo, São Paulo, Brazil, Barnard College, New York, USA, and the American Museum of Natural History, New York, USA.