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至24个月的研究。该计划的奖项提供了联合研究的机会，以及使用国外独特或互补的设施，专业知识和实验条件。该奖项将支持伊丽莎白·尼科尔斯博士与英国兰开斯特兰开斯特大学的肯尼思·威尔逊教授一起工作的24个月研究奖学金。寄生和自由生活类群之间的生物相互作用是一系列生态系统过程的基础，包括介导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（例如蠕虫（寄生蠕虫））对全球热带地区的人类和牲畜产生巨大的适应性和经济成本。然而，环境变化如何影响寄生虫传播所涉及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蜣螂-粪便蠕虫模型系统，通过影响自由生活物种和寄生蠕虫之间的相互作用，梳理出土地利用变化影响寄生虫病传播的机制。由于许多蜣螂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（寄生虫）相互作用：野生和家养食草动物的粪口蠕虫，以及野生和家养食肉动物的营养传播蠕虫（当它们吃成虫时）。初步数据表明，粪甲虫粪便处理往往会降低粪口蠕虫的成功传播率，但会增加营养型传播蠕虫的传播，甲虫通常充当中间宿主。这些截然不同的结果表明，改变蜣螂群落多样性的土地利用变化可能同时抑制和维持或放大疾病在不同哺乳动物宿主物种之间的传播。此外，这些影响的大小和方向可以通过一小部分蜣螂物种的性状来预测。 本研究结合田间、实验和模拟方法，探讨了粪甲虫群落对寄生虫传播的调控机制，以及土地利用变化对传播动态的影响，在基础层面上，本研究将（1）加深我们对传播动态机制及其对土地利用变化的响应的理解，和（2）有助于开发一种新的模型系统，该系统可以扩展现有的单微寄生虫传播模型，以评估多个复杂的生命周期寄生虫物种如何响应自由生活物种多样性的变化。热带农业景观中蠕虫（寄生虫）的经济和健康影响是巨大的。在应用层面，这项工作将提供有用的信息，说明农业地区的环境变化如何影响与生态系统服务成果密切相关的物种相互作用，如减少疾病传播。除了这些好处，这项研究将有助于发展新的国际合作之间的PI和研究小组在兰开斯特大学，兰开斯特英国，拉夫拉斯的联邦大学，拉夫拉斯巴西，圣保罗大学，巴西圣保罗，巴纳德学院，纽约，美国和自然历史博物馆，纽约，美国。

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.