Ecological Factors Promoting Polyphagy in Insect Herbviores

因为大多数毛毛虫以其环境中非常小的一部分植物物种为食，所以饮食广泛的物种（通才）的存在是一个谜。在这个项目中，一组多面手森林毛虫将被用来测试两种关于它们如何维持广泛饮食的假设：“生态权衡假设”和“风险扩散假设”。为了验证这些假设，将在三年内在两个地点的八种不相关的寄主植物上检查四种毛毛虫的生存，生长和繁殖。将比较寄主植物在不同生命阶段遭受天敌（捕食者和寄生虫）攻击的风险。此外，还将通过在每个站点对毛虫进行实地普查，量化寄主植物偏好的背景模式，以确定昆虫偏好是否具有适应性。本研究结果将阐明天敌在昆虫食性广度进化中的重要性这一尚未解决的争论。由于大量的经济害虫是通用性的，发展我们对寄主植物关联如何发展和维持的理解有助于长期的生物防治工作。本项目的一个重要方面是昆虫进化生态学基础教育模块的开发和实施。此外，该项目还将培养一支从事生态研究的本科生队伍。

Because most caterpillars feed on a very small subset of the plant species in their environment, the existence of species with broad diets (generalists) is enigmatic. In this project, a set of generalist forest caterpillars will be used to test two alternative hypotheses for how their broad diets are maintained: the 'ecological tradeoffs hypothesis' and the 'risk-spreading hypothesis.' To test these hypotheses, the survival, growth, and reproduction of four caterpillar species will be examined on eight unrelated host plant at two sites over three years. The risk of attack from natural enemies (predators and parasites) will be compared among host plants at multiple life stages. In addition, the background pattern of host plant preference will be quantified through field censuses of caterpillars at each site to determine if insect preferences are adaptive. The results of this study will illuminate the unresolved debate over the importance of natural enemies in the evolution of insect diet breadth. Because a large number of economic pests are generalists, developing our understanding of how host plant associations develop and are maintained can aid long-term biological control efforts. An important facet of this project is the development and implementation of an elementary education module on insect evolutionary ecology. In addition, the project will train a team of undergraduates in ecological research.