Coevolution and Selective Abscission in the Yucca-Yucca Moth Interaction

生态专门化是推动生物多样性和物种形成的强大引擎。出于这个原因，理解专业化的途径是很重要的：新特征真正新颖的频率是多少，它们什么时候通过对已有特征的修改而产生？这个问题的答案对我们理解相互作用的进化可塑性有重大影响。这个问题将以高度专业化的丝兰和丝兰蛾为模型系统进行探讨。这些物种相互依赖繁殖，蛾是植物的唯一传粉者，丝兰种子是蛾幼虫的唯一食物。幼果的选择性脱落机制使植物能够平衡飞蛾对种子的破坏程度和授粉质量。该项目探讨了脱落机制的组成部分是新的还是对先前存在的性状的修改。首先，我们将进行实验，以检验丝兰家族中更多的基础成员是否存在基于授粉质量的选择性脱落。其次，通过实验方法研究丝兰蛾及其近缘种卵中化学因子对种子发育的影响，探讨其生理机制。这些实验的结果将提供对共同进化和预适应在生态特化中的作用的详细理解。这些问题的答案可以对应用生物学产生直接影响，例如，我们如何管理新的农业害虫。

9509056 Pellmyr Ecological specialization is a powerful engine driving diversification and species formation among organisms. For this reason, it is important to understand the pathways of specialization: how often are new traits truly novel, and when do they arise through modification of preexisting traits? Answers to this question have major bearing on our understanding the evolutionary plasticity of interactions. This issue will be explored using highly specialized yuccas and yucca moths as a model system. These species depend on each other for reproduction, with the moth being the sole pollinator of the plant and yucca seeds being the exclusive food of the moth's larvae. A mechanism of selective abscission of young fruit allows the plant to balance the degree of seed destruction caused by the moth against pollination quality. This project explores whether components of the abscission mechanisms are novel or modifications of preexisting traits. First, experiments will be performed to test whether selective abscission based on pollination quality exits in more basal members of the yucca family. Second, the physiological mechanism mediating abscission will be explored, using an experimental approach to test the effect of a chemical faator from eggs of yucca moths and their relatives on seed development. The results from these experiments should provide a detailed understanding of the role of coevolution and preadaptations in ecological specialization. The answers can have immediate implications for applied biology in, for example, how we manage new agricultural pests.