Density-Dependent Host Acceptance Behavior as a Possible Contributing Factor to the Population Dynamics of Insect Herbivores

密度依赖性宿主接受行为是食草动物种群动态的可能影响因素

• 批准号: 9629776
• 负责人: Kenneth Raffa
• 金额: $ 21万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-01-01 至 1999-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9629776&HistoricalAwards=false
• 关键词: Density; Dependent; Host; Acceptance; Behavior

9629776 Raffa Host plants can strongly affect insect population dynamics. Eruptive species undergo order-of-magnitude changes, exhibit qualitatively different phases, and impact sustainable resource management. This project will investigate interactions between population density and host acceptance behavior as a contributing factor to insect outbreaks. Specifically, population density and behavior may exert mutually positive feedback. This hypothesis will be tested using bark beetles, which are major mortality agents to conifers. Local populations are usually limited to stressed trees, but under some conditions, they can kill almost all host trees regardless of prior vigor. Underlying mechanisms by which bark beetles convert from endemic to outbreak densities are not well understood. Several aspects of their plant relations suggest a link between density-mediated host selection behavior and numerical change: 1) Beetles locate stressed trees using chemical and other cues; 2) Once entered, their likelihood of success is affected by both host resistance and the number of beetles responding to pheromones: Rapid concentration can collectively deplete host defense; 3) Field observations suggest different categories of trees may be selected during endemic and eruptive phases. To test whether changes in host selection behavior influence population dynamics, one must first understand whether individual behavior changes with density. This project will test three nonexclusive hypotheses: 1) Individuals become less discriminating as they age or deplete energy; 2) Actions of other beetles, e.g. pheromones, raise repellent thresholds; 3) Selective pressures vary with population density. These questions will be addressed using one eruptive and one non-eruptive species, the spruce beetle and pine engraver, respectively. A common laboratory assay will evaluate the effects of age, repeated rejection, flight and lipid depletion, synthetic pheromones and the presence of other beetles, and popu lation phase and response to selection. Bark beetles are responsible for severe economic damage to various conifer species. Understanding sources of variability in bark beetle host acceptance behavior will improve the ability to manage sustainable forest ecosystems.

9629776 Raffa寄主植物可强烈影响昆虫种群动态。 爆发物种经历数量级的变化，表现出质的不同阶段，并影响可持续的资源管理。 本计画将探讨虫口密度与寄主接受行为之间的交互作用，作为昆虫爆发的一个促成因素。 具体地说，人口密度和行为可以发挥相互积极的反馈作用。 这一假设将测试小蠹，这是主要的死亡代理针叶树。 当地种群通常仅限于受压树木，但在某些条件下，它们可以杀死几乎所有宿主树木，无论其先前的活力如何。 小蠹从地方性密度转变为爆发密度的潜在机制还不清楚。 它们的植物关系的几个方面表明密度介导的宿主选择行为和数量变化之间的联系：1）甲虫使用化学和其他线索定位受胁迫的树木; 2）一旦进入，它们成功的可能性受到宿主抗性和响应信息素的甲虫数量的影响：快速集中可以集体耗尽宿主防御; 3）野外观察表明，在地方病和爆发阶段，可以选择不同的树种。 为了检验寄主选择行为的变化是否影响种群动态，必须首先了解个体行为是否随密度而变化。 该项目将测试三个非排他性假设： 1)个体随着年龄的增长或能量的耗尽而变得不那么有鉴别力; 2）其他甲虫的行为，例如信息素，提高了驱虫阈值; 3）选择压力随种群密度而变化。 这些问题将使用一个爆发和一个非爆发物种，云杉甲虫和松树雕刻，分别解决。 一个常见的实验室测定将评估年龄的影响，重复拒绝，飞行和脂质消耗，合成信息素和其他甲虫的存在，和population阶段和选择的反应。 树皮甲虫对各种针叶树种造成严重的经济损失。 了解树皮甲虫宿主接受行为的变异性来源将提高管理可持续森林生态系统的能力。