Dissertation Research: Plant-herbivore community assembly and the problem of specificity: Do insect herbivores specialize among sympatric, congeneric plants in tropical forests?

在厄瓜多尔半公顷的热带森林中，树木种类比欧洲、亚洲和北美温带地区的总和还要多。 这就提出了一个问题，即大量生态相似的物种如何在激烈的光、水、空间和营养竞争中共存。 一种流行的观点认为，昆虫可能会在植物变得丰富的时候和地点攻击成功的植物，从而使稀有植物物种占据优势。 然而，这一假设只有在昆虫有高度专门化的饮食时才能成立。 该研究项目将通过研究所有以咖啡科热带森林植物为食的昆虫的饮食来验证这一假设。 为此，将在巴拿马的热带雨林中收集数千只甲虫、毛毛虫、蚱蜢和其他昆虫。 为了识别特定昆虫所食用的植物，将从昆虫胃中提取DNA，并使用每种植物特有的DNA特征来识别它所来自的植物。 还将研究植物的化学差异，以保护它们免受虫害。 研究结果将用于研究植物化学是否影响昆虫取食，以及昆虫是否足够专业化，以通过食用最丰富的植物物种来维持热带森林的植物多样性。 阐明昆虫在维持热带雨林树木多样性方面的作用将揭示地球上最多样化的生态系统中持续存在的奥秘之一。这项拟议中的研究需要密歇根大学的分子实验室工作以及巴拿马史密森热带研究所设施的实地考察，为学生提供跨学科培训的机会。 分子方法的实验室工作将包括在密歇根大学为非传统和代表性不足的学生开设的课程中培训两名研究生。 此外，这项研究将为密歇根大学和史密森热带研究所的公共收藏提供昆虫和植物标本的样本和分子数据。

There are more tree species in a half-hectare of tropical forest in Ecuador than in all of temperate Europe, Asia, and North America combined. This raises the question of how large numbers of ecologically similar species manage to coexist despite intense competition for light, water, space, and nutrients. One popular idea argues that insects may give an advantage to rare plant species by attacking successful plants when and where they become abundant. Yet this hypothesis could only work if insects have highly specialized diets. This research project will test that hypothesis through a study of the diet of all insects that are found to eat tropical forest plants in the coffee family. To this end, several thousand beetles, caterpillars, grasshoppers, and other insects will be collected in the rainforest in Panama. In order to identify the plants that a particular insect has eaten, DNA will be taken from the insect stomachs and the plant from which it came identified using DNA signatures unique to each species of plant. Plants will also be studied for differences in their chemistry that may protect them from insect pests. Results will be used to examine whether plant chemistry influences insect feeding, and whether insects are specialized enough to maintain the plant diversity of tropical forests by eating the most abundant plant species. Illuminating the role of insects in maintaining the tree diversity of tropical rainforests will shed light on one of the persistent mysteries of earth's most diverse ecosystem.The proposed research requires molecular lab work at the University of Michigan as well as fieldwork at facilities of the Smithsonian Tropical Research Institute in Panama, providing opportunity for interdisciplinary training of students. Laboratory work in molecular methods will include training of two graduate students in a University of Michigan program for non-traditional and underrepresented students. Furthermore, this research will contribute samples and molecular data on insect and plant specimens to public collections at the University of Michigan and the Smithsonian Tropical Research Institute.