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重大影响。这些群体被认为是如此多样化的一个原因是它们之间的相互作用。植物的进化变化可以影响昆虫的进化变化，这可能是新物种形成的一种机制，也是进化生物学研究的一个核心问题。这些相互的进化反应可能是由植物和昆虫之间两种不同类型的相互作用引起的。一种被称为互惠的相互作用对两个物种都是有利的。例如，昆虫传粉者在收集食物时在植物之间传播花粉，植物和昆虫都从这种相互作用中受益。第二种类型的相互作用是对抗，其中一个物种以牺牲另一个物种为代价而受益。昆虫以植物为食是拮抗作用的一个例子，这种拮抗作用导致有毒植物化学物质的进化，其中许多化学物质被用于医疗用途。一个悬而未决的主要问题是，在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拮抗作用的结果。了解两者的相对作用对于预测植物和昆虫如何随着时间的推移相互响应至关重要，并将有助于指导增加昆虫授粉服务和减少害虫影响的策略。此外，这项研究将用于为中学生创建一个研讨会，通过实践实验来检验植物-昆虫相互作用在自然和农业环境中的重要性。该研究将使用共同进化和适应性辐射的教科书示例来测试互惠和拮抗共同进化在产生生殖隔离和物种形成中的相对作用。丝兰与丝兰蛾传粉者之间的专门性相互作用既有互惠性又有拮抗性。雌蛾用特殊的触手状口器收集花粉，并主动为丝兰授粉，然后在发育中的丝兰种子附近产卵，供幼虫食用。触角的进化被认为是传粉蛾相互作用和多样化的一个关键创新。虽然以往的研究强调了拮抗性状的性状差异，但尚未对关键的互惠性状、蛾触须或传粉行为的性状差异进行比较调查。互惠和拮抗性状的比较分析将结合传粉者对原生丝兰和非原生丝兰物种的表现试验。具体来说，我们将比较飞蛾在许多丝兰物种中作为有效传粉者和食草动物的能力。这些分析将与对唯一的通才飞蛾传粉者的寄主形式之间交配能力的研究相结合，以测试互惠或拮抗性状的变化是否有助于促进生殖隔离的形成。该项目将首次直接测试相互作用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.