Can Insect Herbivory Control Grassland Composition, Productivity and Dynamics: An Alternative View

卡森9615184 35年来，越来越多的证据表明，食草昆虫不会危害原生草原和草地（蝗虫除外）。 然而，新的证据表明，昆虫的袭击大大减少了北美大草原上阔叶草本植物或杂类草的多样性和丰富度。 某些昆虫的破坏可能导致草原的多样性减少，更容易受到环境扰动的影响。 本研究的目的是确定是否损害甲虫，本地专业昆虫食草动物，控制分布和丰富的三种本地，克隆黄花，形成大，生产补丁在明尼苏达州的大草原。 研究人员基于Grover的工作提出的假设是，甲虫等专业昆虫通过减少优势植物物种的丰度，特别是在贫瘠的草原上发挥着“关键”作用。 “斑块为中心”的昆虫排斥，移植和竞争实验将在明尼苏达州的原生草原进行，以确定甲虫是否减少了天然草原上的黄花菜的丰度。 这项工作将帮助我们了解一些植物物种是如何变得稀有或受到与人类活动没有密切关系的自然过程的威胁。 此外，许多最重要的农作物是草（例如，玉米和小麦），并受到包括大量杂类草在内的杂草的困扰。 了解和识别那些损害杂类而不是草的昆虫可能会导致更多地使用生物控制剂（例如， 昆虫）来控制杂草。 这将最终减少昂贵且可能有害的除草剂的使用。

9615184 CARSON For more than 35 years evidence has accumulated that herbivorous insects will not harm native prairies and grasslands (with the exception of grasshoppers). New evidence suggests, however, that insect attack dramatically reduces the diversity and abundance of broad-leaved herbaceous plants, or forbs, that occur in North American prairies. Damage by certain insects may lead to less diverse prairies that are more susceptible to environmental perturbations. The goal of this research is to determine if damage by beetles, native specialist insect herbivores, control the distribution and abundance of three species of native, clonal goldenrods which form large, productive patches in the prairies of Minnesota. The investigators' hypothesis, based on work by Grover is that specialist insects, such as beetles, play a "keystone" role especially in infertile grasslands by reducing the abundance of dominant plant species. "Patch-centered" insect exclusion, transplant, and competition experiments will be conducted in native prairies in Minnesota to determine whether beetles reduce the abundance of goldenrods in natural grasslands. This work will help us understand how some plant species become rare or threatened by natural processes that are not strongly related to human activities. Furthermore, many of the most important agricultural crops are grasses (e.g., corn and wheat) and are plagued by weeds including a large number of forbs. Understanding and identifying those insects that damage forbs and not grasses could lead to a greater use of biological control agents (e.g., insects) to control weeds. This would ultimately reduce the use of expensive and potentially harmful herbicides.