Multi-scale herbivore regulation in agroecosystems: role of multiple predator assemblages and bottom-up controls

农业生态系统中的多尺度食草动物调节：多种捕食者组合和自下而上控制的作用

• 批准号: 418678-2012
• 负责人: Costamagna, Alejandro
• 金额: $ 1.82万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=506886
• 关键词: Multi; scale; herbivore; regulation; agroecosystems

Beneficial insects provide important ecosystem services controlling insect herbivores (pests) that result in savings of billions of dollars per year. However, many of the basic mechanisms that natural enemies use to control pests are poorly understood and pest populations frequently reach outbreak levels despite the presence of natural control agents. Herbivore populations are regulated by factors operating at multiple spatial scales. At the landscape scale, natural habitats and crop land may act as sources of beneficial insects that attack agricultural pests. Previous studies have shown that several features of the landscape influence the effectiveness of pest control by natural enemies, including extent of natural vegetation, agricultural field size, and the proximity of other crops that harbor beneficial insects. However, the type of interactions taking place between pests and natural enemies in an agricultural field also determines the level of pest suppression. Interactions may include: 1) effects of the plants in a field as a food sources for pests, and 2) interactions among different natural enemies, that could result in both higher (more efficient) or lower (interference among natural enemies) pest suppression. I plan to conduct a series of experiments in commercial fields to test 1) the extent to which local factors affect pest control in landscapes that harbor varying levels of beneficial insects, 2) the features in the landscape that result in higher levels of pest suppression by beneficial insects, and 3) the combinations of natural enemies most effective at suppressing pests. From a theoretical perspective, these experiments will provide new insights into the regulation of insect herbivores at multiple scales. From a more applied perspective, the results of this research will allow us to focus on groups of natural enemies that are effective at suppressing pests in agricultural landscapes, to conserve and enhance the ecosystem service provided by natural pest control agents, and to reduce the current pesticide load and associated environmental cost of managing insect pests through conventional practices.

有益的昆虫提供了控制昆虫食草动物（害虫）的重要生态系统服务，每年节省数十亿美元。但是，自然敌人用来控制害虫的许多基本机制知之甚少，尽管存在自然控制剂，但害虫种群经常达到爆发水平。 食草动物种群受多种空间尺度运行的因素调节。 在景观规模上，自然栖息地和农作物土地可能充当攻击农业害虫的有益昆虫的来源。先前的研究表明，景观的几个特征会影响天然敌人控制害虫的有效性，包括天然植被的程度，农田的大小以及具有有益昆虫的其他农作物的接近。但是，在农业领域，发生害虫与自然敌人之间发生的相互作用的类型也决定了害虫抑制水平。 相互作用可能包括：1）植物中植物作为害虫的食物来源的影响，以及2）不同天然敌人之间的相互作用，这可能导致较高（更有效）或更低（自然敌人之间的干扰）害虫抑制。 我计划在商业领域进行一系列实验以测试1）局部因素在多大程度上影响有不同水平的有益昆虫的景观中的害虫控制，2）景观中的特征，导致通过有益的昆虫和3）自然敌人的组合最有效地抑制害虫。 从理论的角度来看，这些实验将为多个尺度的昆虫食草动物的调节提供新的见解。 从更加应用的角度来看，这项研究的结果将使我们能够专注于有效抑制农业景观中有害生物的天然敌人，以保护和增强自然有害生物控制剂提供的生态系统服务，并减少当前通过常规做法管理害虫的农药负荷和相关的环境成本。