SG: The role of species interactions and coevolution in speciation

植物和昆虫是拥有大量物种的群体，对自然和农业系统都有很大的影响。这些群体被认为如此多样化的一个原因是他们彼此之间的互动。植物的进化变化会影响昆虫的进化变化，这可能是新物种形成的一种机制，这是进化生物学研究的中心问题。这些相互的进化反应可能是由植物和昆虫之间的两种不同类型的相互作用引起的。一种类型的相互作用被称为互惠互利，对两个物种都是有利的。例如，昆虫传粉者在采集食物时在植物之间传递花粉，植物和昆虫都从这种类型的互动中受益。第二种类型的相互作用是对抗，即一个物种以牺牲另一个物种的利益为代价。昆虫利用植物作为食物是导致有毒植物化学物质进化的对抗性的一个例子，其中许多被用于医疗应用。一个悬而未决的主要问题是，自然界中观察到的植物和昆虫的多样性主要是相互作用还是相互对抗的结果。了解两者的相对作用对于预测植物和昆虫随着时间的推移将如何相互反应至关重要，并将有助于指导增加昆虫提供的授粉服务和减少害虫影响的策略。此外，这项研究还将用于通过动手实验为中学生创建一个研讨会，以检验植物-昆虫相互作用在自然和农业环境中的重要性。这项研究将使用共同进化和适应性辐射的教科书例子来测试互惠和拮抗共同进化在产生生殖隔离和物种形成方面的相对作用。丝兰和它们的丝兰飞蛾传粉者之间专有的特殊相互作用既有互惠的成分，也有拮抗的成分。雌蛾使用特殊的触须口器收集花粉，并为丝兰授粉，然后在发育中的丝兰种子附近产卵，供其幼虫食用。触角的进化被认为是传粉蛾互惠共生和多样化的关键创新。虽然以前的研究已经强调了拮抗性状的性状差异，但还没有关于关键的互惠性状--蛾的触角或授粉行为的性状差异的比较调查。对互惠和拮抗特性的比较分析将与传粉者对出生的丝兰和非出生的丝兰的表现测试相结合。具体地说，我们将比较飞蛾在许多丝兰物种中作为有效传粉者和草食动物的能力。这些分析将结合对唯一通用的传粉蛾物种寄主形式之间的交配能力的检查，以测试互惠或拮抗特征的变化是否有助于促进生殖隔离的形成。该项目将是第一次直接测试相互作用的谱系之间的共同进化和物种相互作用类型如何转化为生殖隔离和物种多样化，将微观进化过程与宏观进化模式联系起来。

Plants and insects are groups with large numbers of species that have big impacts on both natural and agricultural systems. One reason these groups are thought to be so diverse is because of their interactions with one another. Evolutionary change in plants can impact evolutionary change in insects, and this is likely one mechanism by which new species are formed, a central question in evolutionary biology research. These reciprocal evolutionary responses might be caused by two different types of interactions between plants and insects. One type of interaction, termed mutualism, is mutually beneficial to both species. For example, insect pollinators move pollen among plants as they gather food, and both the plants and insects benefit from this type of interaction. A second type of interaction is antagonism, where one species benefits at the cost of the other. Insects use of plants as food is an example of antagonism that has led to the evolution of toxic plant chemicals, many of which are used in medical applications. One major unanswered question is whether the diversity of plants and insects observed in nature is mainly the result of mutualistic or antagonistic interactions. Understanding the relative roles of each is critical for predicting how plant and insects will respond to each other through time and will help guide strategies for increasing pollination services provided by insects and reducing the impact of insect pests. In addition, the research will be used in creating a workshop for middle school students through hands-on experiments examining the importance of plant-insect interactions in natural and agricultural settings. The research will use a textbook example of coevolution and adaptive radiation to test the relative roles of mutualistic and antagonistic coevolution in generating reproductive isolation and speciation. The obligate specialized interaction between yuccas and their yucca moth pollinators has both mutualistic and antagonistic components. Female moths use specialized tentacular mouthparts to collect pollen and actively pollinate yuccas, and then deposit eggs near developing yucca seeds that their larvae eat. The evolution of tentacles has been suggested to be a key innovation in the mutualism and diversification of pollinator moths. Although previous research has highlighted trait divergence in antagonistic traits, there has been no comparative survey of trait divergence in the key mutualistic trait, moth tentacles, or of pollination behavior. Comparative analyses of mutualistic and antagonistic traits will be combined with tests of performance of pollinators on natal vs. non-natal yucca species. Specifically, we will compare the ability of moths to be effective pollinators and herbivores across many yucca species. These analyses will be combined with the examination of mating abilities among host forms of the only generalist moth pollinator species to test if changes in mutualistic or antagonistic traits are instrumental in promoting the formation of reproductive isolation. The project will be the first direct test of how coevolution and the type of species interaction among interacting lineages translates into reproductive isolation and species diversification linking microevolutionary processes with macroevolutionary patterns.