Aphid protective symbionts as unseen drivers of population and community dynamics and the impact for biological control

研究背景蚜虫是重要的农业害虫，以植物为食，传播毁灭性的植物病毒。生物控制方法越来越多地被用于防治蚜虫，通过将天敌引入农业生态系统或管理农业生态系统以支持更多的天敌。我们的研究调查了抑制蚜虫的根际细菌、寄生蜂、昆虫病原真菌和野花条对减少作物上蚜虫种群的影响。几乎所有蚜虫都宿主一个初级细菌共生体和许多次级细菌共生体。后者可以带来广泛的好处，包括对昆虫病原真菌和寄生性天敌的抗性，但以牺牲蚜虫的生殖产量为代价。因此，蚜虫共生体可以影响蚜虫种群的生长、动态，并降低生物防治的功效。大多数蚜虫共生体研究都是关于豌豆蚜虫的模型，但物种特异性的结果意味着这些很难外推到其他蚜虫。麦长管蚜（Sitobionavenae）是一种研究比较广泛的蚜虫，其共生体数量比其他蚜虫种类多，为研究蚜虫共生体群落提供了一个有用的系统。本计画将利用控制实验来研究蚜虫共生体如何改变蚜虫族群动态，进而影响生物防治。目标1.从田间采集的样品中开发一套实验性的谷物蚜虫共生体系，通过抗生素固化和显微注射来操纵蚜虫内部微生物组。2.确定寄主内共生体在不同天敌（昆虫病原真菌和寄生蜂）的挑战下的成本和收益.为了遵循人口/社区动态随着时间的推移，使用人工社区mesocosms和现场experimentsNovelty和TimelinessA最近的荟萃分析强调缺乏特定物种的信息，谷物蚜虫及其细菌共生体，而最近的实地研究表明，强烈的反应，共生体社区田间管理和丰富的天敌。我们建立的研究系统使用了广泛的天敌和蚜虫抑制根际细菌，具有广泛的机会，创造人工社区，以遵循蚜虫共生体线的人口/社区动态。

BackgroundAphids are important agricultural insect pests that feed on plants and transmit devastating plant viruses. Biological control methods are increasingly being used to combat aphids, either by introducing natural enemies into the agroecosystem or managing the agroecosystem to support higher numbers of natural enemies. Our research investigates effects of aphid-suppressing rhizobacteria, parasitoid wasps, entomopathogenic fungi, and wildflower strips for reducing aphid populations on crop plants.Almost all aphids host a primary bacterial symbiont and many host secondary bacterial symbionts. The latter can confer wide benefits, including resistance to natural enemies as entomopathogenic fungi and parasitoids, but at a cost to aphid reproductive output. Thus, aphid symbionts can impact aphid population growth, dynamics, and reduce the efficacy of biological control. Most aphid-symbiont research has been on the model pea aphid, but species-specific outcomes mean these are difficult to extrapolate to other aphids. The cereal aphid (Sitobion avenae) has been relatively widely studied and tends to host more symbionts than many other studied aphid species, providing a useful system to study aphid symbiont communities. This project will use controlled experiments to investigate how aphid symbionts alter aphid population dynamics with consequences for biological control. Objectives1. To develop a set of experimental cereal aphid-symbiont lines from field collected samples, by manipulating the aphid internal microbiome through antibiotic curing and microinjections. 2. To determine the costs and benefits of hosting endosymbionts when challenged with different natural enemies (entomopathogenic fungi and parasitoids).3. To follow population/community dynamics over time using artificial community mesocosms and field experimentsNovelty and TimelinessA recent meta-analysis highlighted the lack of species-specific information for cereal aphids and their bacterial symbionts, while recent field studies have shown strong responses of symbiont communities to field management and the abundance of natural enemies. Our established research system uses a wide range of natural enemies and aphid-suppressing rhizobacteria, with broad opportunities to create artificial communities to follow the population/community dynamics of aphid-symbiont lines.