Trophic and guild interactions in biological control

生物防治是利用天敌（病原体、捕食者、寄生虫）来抑制害虫种群。它是一种可行的、可持续的合成农药替代品。我的研究旨在确定农业生态系统中节肢动物群落中多物种相互作用的一些控制生态原则和机制。从应用的角度来看，这项研究是必要的，因为天敌之间的负相互作用可能会损害生物防治计划的有效性。本项目将解决与种群内相互作用（即共享相同资源的同一营养水平物种之间的相互作用）和寄生蜂对宿主行为的操纵有关的基础和应用问题。利用分子生态学和行为生态学的方法，我希望确定和量化决定大豆田蚜虫捕食者之间以及捕食者与寄生蜂之间捕食率的生态和非生物因素。我的计划的第二个轴与寄生蜂进化的利用宿主的策略有关，以及改变行为可能对生物控制的影响。我们最近观察到寄生蜂诱导其瓢虫寄主充当“保镖”：寄主保持靠近寄生蜂蛹，并表现出一系列攻击/防御行为，以保护寄生蜂茧免受天敌的侵害。此外，瓢虫经常从寄生中恢复。我打算回答关于主机行为操纵的三个重要问题。首先，寄生在多大程度上损害了球菌的适应性？第二，自然界中有大量的瓢虫从寄生中恢复过来吗？最后，从应用的角度来看，在田间条件下，被寄生的瓢虫与未被寄生的瓢虫是否具有内在相同的调节蚜虫种群的能力？

Biological control is the use of natural enemies (pathogens, predators, parasites) to suppress a pest population. It is a viable and sustainable alternative to synthetic pesticides. My research is aimed at identifying some of the governing ecological principles and mechanisms of multispecies interactions within arthropod communities found in agroecosystems. From an applied perspective, this research is essential because negative interactions between natural enemies may compromise the effectiveness of biological control programs. The present project will address fundamental and applied questions related to intraguild interactions (i.e. interactions between species at the same trophic level that share the same resource) and host behavior manipulation by parasitic wasps. Using approaches in molecular ecology and behavioral ecology, I wish to identify and quantify ecological and abiotic factors that determine the incidence of predation among species of aphid predators, as well as between predators and parasitic wasps in soybean fields. A second axis of my program relates to strategies evolved by parasitic wasps to exploit their host, and the impact of altered behaviors may have on biological control. We have recently observed that a parasitic wasp induces its coccinellid host to behave as a "bodyguard": the host remains close to the parasitoid pupae and displays a range of aggressive/defensive behaviors that protect parasitoid cocoon against its natural enemies. Furthermore, the coccinellids often recover from parasitism. I plan to answer three important questions on the host behavior manipulation. First, to what extent does parasitism impair coccinellid fitness? Second, are coccinellids recovering from parasitism abundant in nature? Finally, from an applied perspective, do parasitized coccinellids have intrinsically the same capacity to regulate aphid populations as unparasitized conspecifics under field conditions?