Evolution of Cheaters in an Obligate Mutualism: An Experimental Approach

0075944 Pellmyr互惠互动创造了被寄生虫利用的资源。这些寄生虫有时从互利主义者进化而来，它们可以极大地改变相互作用的动态。专性互惠，如种子寄生传粉者和它们的宿主之间的互惠，由于其简单性，成为研究这种逆转的极好模型。这项研究将使用最近进化的骗子丝兰蛾和它的授粉姐妹物种来测试它如何进化的任何专性互利共生的第一个明确的场景。在这种情况下，特定的生活史特征和生态环境，建议大大促进这种类型的多样化。该项目有三个目标。首先，该研究将使用基于mtDNA和形态测量数据的系统发育分析来测试关于在过去的200 - 300万年中作弊者，两种传粉者及其共享宿主之间的地理范围和共存历史变化的明确假设。其次，实验将被用来测试的假设，即传粉者，产生了骗子具有必要的行为可塑性和产卵器形态，使从传粉者到骗子的习惯比较容易的转变。第三，这项研究将测试一个假设，即共存的传粉者之间的偏移羽化物候促进了后来物种的欺骗进化。总之，这个项目将把一个多物种的互惠在其历史地理背景下，并使用一个非常近期的情况下，欺骗的进化互惠作为一个模板，实验测试具体的，但概括的假设，这在生态上重要的多样化过程。

0075944PellmyrMutualistic interactions create resources that are exploited by parasites. These parasites sometimes evolve from mutualists and they can greatly alter the dynamics of the interactions. Obligate mutualisms, such as those between seed-parasitic pollinators and their hosts, make excellent models for the study of such reversals because of their simplicity. This study will use a recently evolved cheater yucca moth and its pollinating sister species to test the first explicit scenario for any obligate mutualism of how it can evolve. In this scenario, specific life history traits and ecological context are suggested to greatly facilitate this type of diversification. The project has three objectives. First, the study will use phylogenetic analysis based on mtDNA and morphometric data to test explicit hypotheses about changing geographic ranges and history of coexistence between the cheater, two pollinators, and their shared host over the last 2-3 million years. Second, experiments will be used to test the hypothesis that the pollinator that gave rise to the cheater has requisite behavioral plasticity and ovipositor morphology to make the shift from pollinator to cheater habit comparatively easily. Third, the study will test a hypothesis suggesting that offset emergence phenology between coexisting pollinators facilitates the evolution of cheating in the later species. Taken together, this project would place a multi-species mutualism in its historical biogeographic context, and use a very recent case of evolution of cheating within that mutualism as a template to experimentally test specific but generalizable hypotheses about this ecologically important process of diversification.