Collaborative Research: Influence of below-ground species interactions on dynamics above ground: Trait-mediated indirect effects from soils to parasites of leaf-feeding herbivores

几乎所有已知的生物，从人类到大豆，都受到引起疾病的寄生虫的攻击。寄生虫的传播速度各不相同，这影响了它们传播的速度；它们的毒力是衡量它们对宿主健康恶化程度的指标。最近的研究表明，环境中的其他生物体可以影响寄生虫的传播和毒力。例如，黑脉金斑蝶食用的马利筋植物中的抗生素可以保护蝴蝶免受寄生虫的侵害，而已经感染寄生虫的雌性黑脉金斑蝶更喜欢在含有高浓度抗生素的植物上产卵。但是是什么使得一种马利筋比另一种含有更多或更少的抗生素呢？土壤中的真菌与植物根系相互作用，影响植物叶片中抗生素的浓度，因此可能决定地面上的寄生率。该项目以帝王蝶为模型，探索土壤真菌、植物、食草动物及其寄生虫之间的相互作用。研究人员推测，土壤中真菌的丰度和特性有助于确定地面上蝴蝶的感染率，并且被土壤真菌殖民的植物对已经感染寄生虫的产卵蝴蝶更有吸引力。这项工作具有广泛的影响，超出了蝴蝶的研究。该项目研究的寄生虫与引起人类疟疾的寄生虫有关，因此这项研究可能有助于了解人类寄生虫的传播和毒性。许多农作物害虫都有寄生虫，通过管理土壤真菌可以使寄生虫更有效。在这个项目中接受培训的学生将来自不同的背景，并加入密歇根大学和埃默里大学建立的指导计划。学校教师将制定与该项目相关的教学计划，而帝王蝶在向公众传授科学原理方面仍然很受欢迎。

Almost all known organisms, from humans to soybeans, are attacked by parasites that cause disease. Parasites vary in their transmission rate, which influences how quickly they can spread; and in their virulence, a measure of how strongly they worsen the health of their hosts. Recent research now shows that other organisms in the environment can influence the transmission and virulence of parasites. For example, antibiotics in milkweed plants that are eaten by monarch butterflies can protect the butterflies from parasites, and female monarchs that are already infected with parasites show a preference for laying their eggs on plants containing high concentrations of the antibiotics. But what makes one milkweed plant contain more or less antibiotic than another? Fungi in the soil interact with the roots of plants to influence the concentration of antibiotics in plant leaves, and so may be determining rates of parasitism above ground. Using monarchs as a model, this project explores interactions between soil fungi, plants, herbivores, and their parasites. The researchers hypothesize that the abundance and identity of the fungi in the soil help determine the infection rates of the butterflies above ground, and that plants that are colonized by soil fungi become more attractive to egg-laying butterflies that are already infected with parasites.This work has broad impacts beyond the study of butterflies. The parasites studied in the project are related to those that cause malaria in humans, so the research may help understand the transmission and virulence of human parasites. Many crop pests have parasites that might be made more effective by managing soil fungi. Students trained on this project will come from diverse backgrounds and join established mentoring programs at the University of Michigan and Emory University. Schoolteachers will develop teaching plans in association with the project, and monarch butterflies remain popular for teaching scientific principles to the general public.