Effects of "Bottom-Up", "Lateral", and "Top-Down" Forces on the Structure of a Phytophagous Insect Community

“自下而上”、“横向”和“自上而下”力对植食性昆虫群落结构的影响

• 批准号: 9527846
• 负责人: Robert Denno
• 金额: $ 23万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-03-01 至 2000-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9527846&HistoricalAwards=false
• 关键词: Effects; Bottom; Up; Lateral; Top

9527846 Denno The relative importance of plant characteristics ("bottom-up") and natural enemies ("top-down factors") in the population and community ecology of phytophagous (plant-feeding) insects has been disputed for decades. Add to this the effects of competition ("lateral factors") on herbivorous insect communities and the issue becomes more complicated. To date, very few studies have determined whether: (1) "bottom-up", "lateral", and "top-down" forces act in concert, (2) important interactions exist among these forces, and (3) each herbivore species is influenced by different factors such that no single force dictates community organization. The present research employs an experimental approach in which host plant quality, competition, and predation are manipulated to understand the factors which influence the plant-feeding insect community in intertidal marshes of eastern North America. The major organisms are salt marsh cord grass, its dominant sap-feeding insects, and their major predators, hunting spiders. Existing evidence suggests that "bottom-up", "lateral", and "top-down" forces are all potentially important in this system, and that each herbivore species responds to these forces differently. Thus, this system provides the exciting opportunity to assess how these forces integrate to determine the abundance of each herbivore species. The proposed research will make a significant contribution toward unraveling the interactions most influential in dictating the distribution and abundance of plant-feeding insects. The sensitive wetland ecosystem that will be studied is strikingly similar to many agricultural cropping systems such as rice, corn, and sugar cane. Similarities include the uniformity of the habitat, as well as the types of herbivorous insects and their natural enemies. The results of this study will provide critically-needed information on the importance of host-plant factors (fertilizer regimes and varietal resistance) and biological control agents and how they interact to suppress agricultural pest populations.

小行星9527846 在植食性昆虫种群和群落生态学中，植物特征（自下而上）和天敌（自上而下）的相对重要性几十年来一直存在争议。 再加上竞争（“横向因素”）对植食性昆虫群落的影响，问题变得更加复杂。 到目前为止，很少有研究确定：（1）“自下而上”，“横向”和“自上而下”的力量是一致的，（2）这些力量之间存在重要的相互作用，（3）每个草食动物物种受到不同因素的影响，没有一个单一的力量决定社区组织。 本研究采用了一种实验方法，其中宿主植物的质量，竞争和捕食被操纵，以了解影响北美东部潮间带沼泽植食性昆虫群落的因素。 主要的生物是盐沼绳草，它的优势树液喂养昆虫，和他们的主要捕食者，狩猎蜘蛛。 现有的证据表明，“自下而上”，“横向”和“自上而下”的力量都是潜在的重要在这个系统中，每个草食动物物种对这些力量的反应不同。 因此，这个系统提供了一个令人兴奋的机会，以评估这些力量如何整合，以确定每一个食草动物物种的丰度。 这项研究将为揭示在决定食草昆虫的分布和丰度方面最有影响力的相互作用做出重大贡献。 将要研究的敏感湿地生态系统与许多农业种植系统（如水稻、玉米和甘蔗）惊人地相似。 相似之处包括栖息地的一致性，以及食草昆虫及其天敌的类型。 这项研究的结果将提供急需的信息的重要性，寄主植物的因素（施肥制度和品种抗性）和生物控制剂，以及它们如何相互作用，以抑制农业害虫种群。