Collaborative research: Disease ecology in the midst of anthropogenic stressors: Exploring the influence of pesticides on host-parasite interactions

野生种群越来越多地受到人类活动的影响，包括栖息地破坏、引入物种和污染。随着人类人口的持续增长，以及我们对食物的需求，我们对杀虫剂控制各种害虫的依赖将会加剧。因此，农药对自然系统的污染将持续存在。最近的研究表明，一些暴露在杀虫剂下的野生种群可以在多个世代之间进化出耐受性，或者在一代内诱导耐受性。当接触杀虫剂时，这两种机制都可以提高存活率。然而，每种机制都可能导致不同的成本，从而改变生物体与其社区其他成员互动的方式。越来越多的研究集中在农药对寄主和寄生虫相互作用的影响上。然而，研究对农药的进化反应对疾病动态的影响的研究仍然有限。这项研究试图了解对污染物的进化反应可能如何影响水生群落中宿主与寄生虫的相互作用。具体地说，本研究提出了以下问题：(1)寄主和寄生虫能否进化出对农药的耐受性？2)寄主和寄生虫能否在一代内诱导对农药的耐受性？3)这两种不同的耐受机制如何影响寄主-寄生虫的相互作用？这项研究解决了两个社会关注的问题，如环境污染和病原体传播。此外，该项目的重点是全球正在减少的类群(即两栖动物)和日益受到保护关注的栖息地(即湿地)。调查人员将为K-12教育工作者开发一个教学模块。教学模块将突出进化论和生态学在现代毒理学中的作用。该研究还将为包括少数民族、女性和第一代大学生在内的本科生和研究生提供培训。总之，这项研究可以提供有价值的信息，可以用来从应用和基础研究的角度来理解农药的影响。本研究将以最近观察到的与农业邻近相关的进化和诱导的农药耐受性为基础，探索农药耐受性如何影响宿主-寄生虫的相互作用。这项研究将使用一种寄生虫(棘足虫)及其中间水生宿主物种(池塘蜗牛和幼虫林蛙)。利用这些寄主和寄生虫生活阶段的一系列毒性和宿主感染分析，拟议的研究将：(1)分析不同农业土地利用梯度的基线农药耐受性的景观格局。研究人员预测，农业较多的寄生虫和蜗牛种群的基线杀虫剂耐受性将高于农业较少的种群。(2)评价自然人群中诱导性农药耐药的发生情况。研究人员预计，在农业较少的人群中，诱导的杀虫剂耐受性比农业较多的人群更大。(3)确定原生性和诱导性农药耐受性对寄主-寄生虫相互作用的影响。研究人员预测，这种相互作用的结果将取决于宿主和寄生虫对杀虫剂的相对敏感性。

Wild populations are increasingly influenced by human activities including habitat destruction, introduced species, and pollution. As the human population continues to grow, along with our needs for food, our reliance on pesticides to control a variety of pests will intensify. Therefore, pesticides contamination of natural systems will persist. Recent research suggests that some wild populations exposed to pesticides can evolve tolerance over multiple generations or induce tolerance within a single generation. Both of these mechanisms can improve survival when exposed to pesticides. However, each mechanism may lead to different costs that alter the way organisms interact with other members of their community. An increasing number of studies have focused on the effects of pesticides on the interaction between host and their parasites. However, research that examines the influence of evolutionary responses to pesticides on disease dynamics remains limited. The study seeks to understand how evolutionary responses to contaminants may affect host-parasite interactions in aquatic communities. Specifically, the study asks the following questions: (1) Can hosts and parasites evolve tolerance to pesticides? 2) Can hosts and parasites induce tolerance to pesticides within a single generation? 3) How do the two different mechanisms of tolerance influence host-parasite interactions? This research tackles two issues of societal interest such as environmental contamination and transmission of pathogens. In addition, the project focuses on taxa that are declining globally (i.e. amphibians) and habitats that are of increasing conservation concern (i.e. wetlands). The investigators will develop a teaching module for K-12 educators. The teaching module will highlight the role of evolution and ecology in modern toxicology. The study will also provide training for undergraduate and graduate students including minorities, women, and first-generation college students. Overall, this study can provide valuable information that can be used to understand the effects of pesticides from both applied and basic research views.This research will use recent observations of evolved and induced pesticide tolerance in relation to proximity to agriculture as a foundation to explore how pesticide tolerance influences host-parasite interactions. The study will use a parasite (Echinoparyphium) and its intermediate aquatic host species (pond snail and larval wood frog). Using a series of toxicity and host-infection assays across these multiple hosts and parasite life stages, the proposed research will: (1) Analyze landscape patterns of baseline pesticide tolerance across a gradient of agricultural land use. The investigators predict that baseline pesticide tolerance will be higher in parasite and snail populations surrounded by more agriculture than in those surrounded by less agriculture. (2) Evaluate the occurrence of inducible pesticide tolerance in natural populations. The investigators expect a greater magnitude of induced pesticide tolerance in populations surrounded by less agriculture than in those surrounded by more agriculture. (3) Determine the effects of constitutive and inducible pesticide tolerance on host-parasite interactions. The investigators predict that the outcome of the interactions will depend on the relative sensitivity of the hosts and parasites to pesticides.