Collaborative Research: Dimensions US-Biota Sao Paulo: Chemically mediated multi-trophic interaction diversity across tropical gradients

这项研究将考察巴西不同景观的森林中植物和相关昆虫的多样性和生态复杂性。植物、昆虫及其捕食者占所有已知生物的一半以上，它们之间的相互作用对生态系统的健康至关重要。对于热带森林来说尤其如此，生态学家才刚刚开始了解这些相互作用的性质和复杂性。特别是，人们对以下方面知之甚少：1)阻止昆虫食草并影响其他动植物的植物化学物质的多样性；2)这些植物化学物质的多样性在植物物种内部和物种之间如何变化；3)植物化学物质如何影响整个森林的多样性和生产力。化学和分子生物学的最新进展为了解植物与昆虫在三个不同层次（化学、遗传和分类）上的相互作用的多样性提供了前所未有的广度和深度。一个由美国和巴西科学家组成的独特团队将整合和加强这些新方法，以调查昆虫-植物食物网的多样性，它们如何受到植物化学防御和环境梯度的影响，以及这种多样性如何影响森林的稳定性和生产力。该研究将有助于了解全球生物多样性和气候变化如何影响植物-昆虫-捕食者的相互作用，植物遗传和化学多样性如何影响植物取食，以及昆虫捕食者的分类和遗传多样性如何影响有害昆虫的控制。该项目中使用的全面采样和方法将导致发现新的植物和昆虫物种，新的生物活性分子，并可能提供在农业和医学中具有强大应用的新工具和方法。这一国际性、多学科的研究项目将产生广泛的影响，涉及K-12学生、科学教师和公民科学家。这些发现将通过网站、科学和通俗出版物向公众广泛传播。该项目重点研究了一个高度多样化的系统，涉及胡椒属植物（胡椒科），相关的食草动物，寄生蜂和苍蝇。本研究将利用最先进的方法来研究生物多样性，将相互作用多样性的测量与遗传多样性、种群遗传结构和植物化学多样性联系起来，涉及以下组成部分：1)在不同地点对不同的Piper物种进行大规模的草食动物及其寄生蜂取样，以评估非生物梯度对群落结构和生态系统过程的影响，并获得用于分类、基因组和植物化学分析的标本。2)在野外实验中，将对分类、遗传和功能多样性与非生物因素一起进行操作，以加强从野外调查、群落遗传学和代谢物多样性测量的统计分析中得出的推论。3)对植物、食草动物和拟寄生物进行分类和系统分析，利用传统和新颖的方法（基因组学）记录和描述新的分类群，了解它们之间的关系，揭示潜在的多样性。4)植物、食草动物和拟寄生物的种群基因组分析，以了解地理、植物系统发育和化学如何影响营养水平上的种群结构和遗传分化。5)胡椒属植物代谢物多样性特征；代谢物多样性如何随系统发育、生态和食草动物压力而变化；以及植物化学多样性对高营养水平的影响。沿着海拔梯度的定量采样、新开发的代谢组学方法、种群基因组学和大规模实验的结合，将使关于植物化学和不同多样性维度之间关系的新兴假设的检验成为可能，并将代表热带地区第一次大规模的、在站点间的植物-草食-寄生性食物网比较。

This research will examine the diversity and ecological complexity of plants and associated insects in forests across a variable landscape in Brazil. Plants, insects, and their predators make up over half of all known organisms, and their interactions are essential to ecosystem health. This is especially true for tropical forests, where ecologists are only beginning to understand the nature and complexity of these interactions. In particular, little is known about: 1) the diversity of plant chemicals that deter insect herbivory and affect other plants and animals, 2) how diversity of these plant chemicals varies within and between plant species, and 3) how plant chemistry can affect the diversity and productivity of entire forests. Recent advances in chemistry and molecular biology provide the opportunity to understand the diversity of plant-insect interactions at three different levels (chemical, genetic, and taxonomic) with unprecedented scope and depth. These new methods will be integrated and enhanced by a unique team of U.S. and Brazilian scientists to investigate the diversity of insect-plant food webs, how they are shaped by plant chemical defenses and environmental gradients, and how this diversity affects forest stability and productivity. The research will contribute to understanding how large global changes in biodiversity and climate will affect plant-insect-predator interactions, how plant genetic and chemical diversity influences plant-feeding, and how taxonomic and genetic diversity of insect predators can affect control of harmful insects. The comprehensive sampling and methods used in this project will result in the discovery of new species of plants and insects, new biologically active molecules, and are likely to deliver new tools and approaches that have powerful applications in agriculture and medicine. This international and multi-disciplinary research project will have broad impacts by involving K-12 students, science teachers, and citizen scientists. Discoveries will be widely communicated to the public via websites, and scientific and popular publications. This project is focused on a highly diverse system involving plants in the genus Piper (Piperaceae), associated herbivores, and parasitic wasps and flies. The research will utilize cutting edge approaches to studying biodiversity that link measures of interaction diversity to genetic diversity, population genetic structure, and plant chemical diversity involving the following components: 1) Large scale sampling of herbivores and their parasitoids on diverse Piper species across an array of sites to assess effects of abiotic gradients on community structure and ecosystem processes, and to acquire specimens for taxonomic, genomic, and phytochemical analysis. 2) Field experiments where taxonomic, genetic, and functional diversity will be manipulated along with abiotic factors to strengthen inferences from statistical analysis of field surveys, community genetics, and measures of metabolite diversity. 3) Taxonomic and systematic analysis of plants, herbivores, and parasitoids using traditional and novel methods (genomics) to document and describe new taxa, understand their relationships, and reveal cryptic diversity. 4) Population genomic analyses of plants, herbivores, and parasitoids to understand how geography, plant phylogeny and chemistry influence population structure and genetic differentiation across trophic levels. 5) Characterization of metabolite diversity of Piper species; how metabolite diversity varies with phylogeny, ecology, and herbivore pressure; and the effect of phytochemical diversity on higher trophic levels. The combination of quantitative sampling along elevational gradients, newly developed metabolomics methods, population genomics, and a large scale experiment will make possible tests of emerging hypotheses about relationships between plant chemistry, and different dimensions of diversity, and will represent the first large scale, among-site plant-herbivore-parasitoid food-web comparison in the tropics.