Developing, unifying, and empirically testing theory for inducible and evolving defenses

在世界各地，被捕食的物种有各种各样的防御措施来避免被捕食者吃掉。塑料防御可以随着时间的推移而改变，这取决于存在多少捕食者，例如，当周围有更多的捕食者时，猎物可能会花更多的时间躲藏。进化的防御（如外壳厚度）会随着时间的推移而改变，这取决于父母存活下来繁殖并能够将其特征传递给后代。这些不同类型的防御会影响猎物及其捕食者的丰度，以及对环境变化的反应。然而，目前尚不清楚塑料和进化防御究竟有什么影响，以及塑料和进化防御对物种丰度及其对环境变化的反应是否有相似或不同的影响。发展这样的理解是很重要的，因为人类正在通过营养丰富和物种死亡戏剧性地改变环境。目前，还不可能预测不同类型的防御（可塑的或进化的）如何决定种群的反应。该项目使用实验室实验和数学模型来确定不同类型的塑料和进化防御如何影响种群丰度以及种群如何应对环境变化。该研究项目将培养社区生态学和数学生物学领域的本科生和研究生，让代表性不足的少数民族参与研究，并通过社区外展活动吸引公众。猎物对捕食压力的适应性反应在本质上可以是可塑性的，也可以是进化性的，两者都可以改变生态群落的动态和稳定性。该项目的目标是发展理论，解释不同类型的塑料防御和进化防御之间的机制差异如何塑造社区的动态。为了确定塑性防御和进化防御何时具有相似或不同的影响，将开发数学模型来解释塑性防御和进化防御如何影响系统稳定性和种群对营养富集和物种死亡率的反应。这一理论将通过实验室实验来验证，实验对象是一种被捕食物种（草履虫），它们有或没有塑料防御——行为和身体宽度的变化——这会改变它们被捕食者吃掉的速度。这项工作既扩展了目前的塑性防御理论，又将其与进化防御理论统一起来。该项目的理论-数据配对方法可能会在塑料防御和群落生态学理论方面取得重要进展。这项工作还将深入了解塑料与进化适应之间的联系。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Throughout the world, prey species have a variety of defenses to avoid being eaten by predators. Plastic defenses are those that can change over time based on how many predators are present, for example prey may spend more time hiding when there are more predators around. Evolving defenses (like shell thickness) change over time based on which parents survive to reproduce and are able to pass their traits to their offspring. These different types of defenses influence the abundances of prey and their predators, as well as responses to environmental change. However, it is unclear exactly what effects plastic and evolving defenses have and whether plastic and evolving defenses have similar or different effects on species abundances and their responses to environmental change. Developing such an understanding is important because humans are dramatically altering environments through nutrient enrichment and species mortality. At present, it is not possible to predict how different types of defense (plastic or evolving) determine how populations will respond. This project uses laboratory experiments and mathematical models to determine how different types of plastic and evolving defenses influence population abundances and how populations respond to environmental change. This research program will train undergraduate and graduate students in the fields of community ecology and mathematical biology, engage underrepresented minorities in research, and engage the public through community outreach activities. Adaptive responses in prey to predation pressure can be plastic or evolutionary in nature, and both can alter the dynamics and stability of ecological communities. The goal of this project is to develop theory that explains how mechanistic differences between different types of plastic defenses and evolving defenses shape the dynamics of communities. To identify when plastic and evolving defenses have similar versus different effects, mathematical models will be developed to explain how plastic and evolving defenses influence system stability and population responses to nutrient enrichment and species mortality. The theory will be tested via laboratory based experiments involving populations of a prey species (Paramecium) that do or do not have plastic defenses - changes in behavior and body width - that alter the rate at which they are consumed by predators. This work will both extend current theory for plastic defenses and unify it with the theory for evolving defenses. The theory-data pairing approach of this project is likely to generate important advances in the theory of plastic defenses and community ecology. This work will also yield insight into the connections between plastic and evolutionary adaptation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.