DISSERTATION RESEARCH: Mutualisms in trophic cascades: the effects of parasites of bumble bees on pollination

这项研究将调查互惠是否可以介导营养级联，特别是熊蜂的寄生虫是否可以影响植物种群，通过三种方法。首先，理论模型将被用来探讨如何相互依赖的互惠互利的变化的影响，互惠互利的人口的拮抗剂。第二，将进行一项多地点调查，将熊蜂寄生的发生率与五种植物的繁殖相关联，这五种植物对熊蜂授粉的依赖程度各不相同。这个设计测试了这样一个预测，即对于更依赖熊蜂的植物，寄生和植物繁殖成功之间将有更强的负相关性。最后，熊蜂行为的研究，使用笼实验将被用来调查寄生觅食行为和授粉效率的影响，并确定是否由于寄生行为的变化会影响授粉。互惠，两个物种之间的生态相互作用，其中双方受益，正在成为生物群落中的主要结构力量。群落生态学中的一个关键概念是营养级联，其中捕食者通过对食草动物的影响来影响植物。然而，这一概念从未被明确地应用于互惠主义。捕食者和寄生虫有可能对猎物和猎物的互惠伙伴产生负面影响。此外，通过互利互动的潜在的营养级联可能会受到合作伙伴相互依赖的程度的影响。更广泛的影响包括培养博士。候选人和潜在的农业应用。寄生虫对管理蜜蜂的种群产生了巨大的影响，但我们才刚刚开始了解它们如何影响本地传粉者。这项研究将使我们能够更好地了解传粉者的拮抗剂，从而帮助我们保护它们对世界经济的2000亿美元价值。

This research will investigate whether mutualisms can mediate trophic cascades, and specifically whether parasites of bumblebees can affect plant populations, via three approaches. First, theoretical models will be used to explore how the interreliance of mutualists changes the effects of antagonists on mutualist populations. Second, a multi-site survey will be conducted, correlating incidence of bumble bee parasitism with reproduction of five plant species that vary in their dependence on bumble bees for pollination. This design tests the prediction that there will be stronger negative correlations between parasitism and plant reproductive success for plants that are more dependent on bumble bees. Finally, studies of bumble bee behavior using cage experiments will be used to investigate the impacts of parasitism on foraging behavior and pollination efficiency, and to establish whether changes in behavior due to parasitism can affect pollination. Mutualisms, ecological interactions between two species in which both benefit, are becoming recognized as major structuring forces in biological communities. A key concept in community ecology is that of the trophic cascade, in which predators affect plants through effects on herbivores. However, this concept has never been explicitly applied to mutualisms. Predators and parasites have the potential to negatively affect both their prey and their prey's mutualist partners. Furthermore, the potential for trophic cascades through mutualist interactions will likely be influenced by the degree to which partners rely on each other. Broader impacts include training of a Ph.D. candidate and potential application to agriculture. Parasites have had a dramatic effect on populations of managed honeybees, yet we are only beginning to understand how they can impact native pollinators. This research will enable better understanding of antagonists of pollinators, thus helping us preserve their $200 billion value to the world economy.