Dimensions: Collaborative Research: Diversification Dynamics of Multitrophic Interactions in Tropical Communities

生物多样性是如何产生和维持的？大量证据表明，寄生虫在生物多样性的起源和维持中起着重要作用。该项目的重点是地球上最多样化的生物群体之一：食草昆虫，它们的寄生虫和微生物。该项目针对三种具有重要经济意义的生物：南瓜/黄瓜科植物、攻击这些植物的真果蝇和杀死果蝇的寄生蜂。这些黄蜂属于一个高度多样化和很少研究的物种组。每种黄蜂只能杀死一种苍蝇;黄蜂攻击“错误”的苍蝇物种会死亡。这些双向致命的相互作用可能是由微生物（黄蜂，苍蝇，或两者），苍蝇的免疫系统的特征，或两者介导的。该项目旨在揭示影响相互作用的机制（进化，生态和免疫），这可能有助于解释生命的多样性。许多种类的实蝇是主要的农业害虫;该项目将大大增加对导致它们易受拟寄生物影响的因素的了解。该项目测试的假设预测：1）寄生虫及其宿主的防御影响多样化率; 2）毒力机制在谱系之间存在差异; 3）捕食者-猎物相互作用产生的选择可以影响物种形成率。为了发现和识别多样化的机制，参与者将生成和分析分子1）高分辨率遗传数据，多个核基因座和mtCOI单倍型，以描绘物种，并解决更深层次的系统发育关系; 2）微卫星和ddRAD-seq标记，以发现和量化种群内和种群间的精细遗传多样性; 3）遗传学和实地实验，以测试关于古代，近代和当代时间尺度上产生和控制多样性的机制的假设。来自所有参与院校的本科生将参与研究。

How is biodiversity generated and maintained? Much evidence suggests that parasites play an important role in both the origin and the maintenance of biological diversity. This project focuses on one of the most diverse groups of organisms on the planet: herbivorous insects, their parasites, and their microbes. The project targets three economically important groups of organisms: plants in the pumpkin/cucumber family, true fruit flies that attack these plants, and parasitic wasps that kill the flies. These wasps belong to a highly diverse and little studied group of species. Each wasp species can kill only one fly species; wasps attacking the "wrong" species of fly die. These bi-directional lethal interactions may be mediated by microbes (in wasps, flies, or both), by traits of flies' immune systems, or both. This project is designed to uncover the mechanisms (evolutionary, ecological, and immunological) affecting interactions that may help explain the diversity of life. Many species of true fruit flies are major agricultural pests; this project will greatly increase knowledge about factors contributing to their susceptibility to parasitoids. The project tests hypotheses that predict that: 1) defenses of parasites and their hosts affect diversification rates; 2) mechanisms of virulence differ among lineages, and 3) selection arising from predator-prey interactions can affect rates of species-formation. To discover and identify mechanisms of diversification, participants will generate and analyze molecular 1) high-resolution genetic data, multiple nuclear loci, and mtCOI haplotypes to delineate species, and resolve deeper phylogenetic relationships; 2) microsatellites and ddRAD-seq markers to discover and quantify fine-scale genetic diversity within and among populations; 3) phylogenies and field experiments to test hypotheses about mechanisms generating and controlling diversity on ancient, recent, and contemporary timescales. Undergraduate students from all participating colleges and universities will participate in the research.