Evolution of pathogen avoidance behavior and downstream effects on physiological resistance

项目摘要 回避是一种针对病原体的寄主防御形式，它降低了寄主和 病原体。回避行为代表了动物对抗病原体的第一道防线，并在 在决定宿主-病原体相互作用是否以及如何进行方面起主要作用。然而，回避并没有 在为其他形式的防御而构建的丰富理论框架内进行了研究 病原体，如生理抗性。回避和抵抗都可以减少感染，因此它可以 可以认为，关于抗药性的大量文献可以简单地扩展到预测生态和 回避的进化动力学。然而，回避的演变可能不同于抵抗，特别是在 避免的成本要么更低，要么更多变。此外，作为寄主病原菌的守门人， 互作、回避可能对抗性的选择强度产生下游影响。 关于回避在确定宿主-病原体相互作用中的主要作用的预测已经得到证实 测试具有挑战性，因为回避和抗药性很难从经验上分开：感染结果是 两者兼而有之。这项研究通过理论和实证相结合的方式解决了这些知识差距 研究以生成和测试回避和抵抗的演变预测作为 “防御工事”理论方法将产生对统治的进化过程的预测 回避及其与抵抗的联系(目标1)。实验将在一个易于处理的系统中进行 哪些回避和抵抗不仅可以单独测量，而且可以单独进化： 模式生物秀丽线虫和细菌病原体粘质沙雷氏菌。化验和 实验选择方案将表征相对于以下方面的适应成本和避免的收益 抵抗(目标2)，并检查单独和组合防御模式的演变(目标3)。 总而言之，这种方法将打破防御级联的步骤，为 了解回避的进化及其对抗性进化的下游影响。这项研究 将使用一种新的方法来弥合行为生态学和病原体进化理论之间的鸿沟 辩护，为解决与避税相关的公共卫生决定奠定了基础 行为。通过拟议的研究，学员将发展复杂数学的技术技能 对线虫实验室进行建模和维护。学员还将专注于专业技能，如 导师关系和协作精神。培训将在加州大学生物系进行。 在两位成功的共同赞助者的监督下，他们将提供不同的观点，以及 有足够的资源支持实习生。通过这一奖学金，实习生将在她强大和 作为一名独立科学家和所在领域的领导者，她拥有多产的背景，以充分发挥其潜力。

Project Summary Avoidance is a form of host defense against pathogens that reduces the risk of initial contact between host and pathogen. Avoidance behaviors represent an animal's first line of defense against pathogens and play a primary role in determining whether and how a host-pathogen interaction will proceed. Yet avoidance has not been studied within the rich theoretical framework that has been built for other forms of defenses against pathogens, such as physiological resistance. Both avoidance and resistance reduce infection, and thus it could be argued that the extensive literature on resistance can be simply extended to predict the ecological and evolutionary dynamics of avoidance. However, avoidance may evolve differently from resistance, especially if the costs of avoidance are lower or more variable. Moreover, as the gatekeeper of the host-pathogen interaction, avoidance is likely to have downstream effects on the strength of selection on resistance. Predictions about the primary role of avoidance in determining host-pathogen interactions have proven challenging to test because avoidance and resistance are hard to separate empirically: infection outcomes are a product of both. This research addresses these knowledge gaps by combining theoretical and empirical research to generate and test predictions for the evolution of avoidance and resistance as components of a `defense cascade.' Theoretical approaches will generate predictions for the evolutionary processes that govern avoidance and its association with resistance (Aim 1). Experiments will be conducted in a tractable system in which avoidance and resistance not only can be measured separately, but also can be evolved separately: the model organism Caenorhabditis elegans and bacterial pathogen Serratia marcescens. Assays and experimental selection schemes will characterize the fitness costs and benefits of avoidance relative to resistance (Aim 2), and examine the evolution of defense modes separately and in combination (Aim 3). Together, this approach will break down the steps of the defense cascade, establishing a critical foundation for understanding the evolution of avoidance and its downstream impacts on resistance evolution. This research will use a novel approach to bridge the gap between behavioral ecology and evolutionary theory of pathogen defenses, laying a foundation to address questions relevant to public health decisions surrounding avoidance behaviors. Through the proposed research, the Trainee will develop technical skills for complex mathematical modeling and maintaining a C. elegans laboratory. The Trainee will also focus on professional skills such as mentorship and collaboration. The training will take place in the Department of Biology at the University of Virginia, under the supervision of two successful co-sponsors who will contribute diverse perspectives, and have the resources to support the Trainee. Through this fellowship, the Trainee will build on her strong and productive background to reach her full potential as an independent scientist and leader in her field.