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

蚜虫是一种重要的农业害虫，以植物为食，传播毁灭性的植物病毒。生物防治方法正越来越多地被用于防治蚜虫，要么将天敌引入农业生态系统，要么管理农业生态系统，以支持更多数量的天敌。本研究研究了抑制根际细菌、寄生蜂、昆虫病原真菌和野生花条对减少作物上的蚜虫种群的影响。几乎所有的蚜虫都有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蜂等天敌的抗性，但代价是蚜虫的繁殖产量。因此，蚜虫共生体会影响到蚜虫种群的增长、动态，并降低生物防治的效果。大多数关于蚜虫共生体的研究都是在豌豆蚜虫模型上进行的，但特定物种的结果意味着这些结果很难推断到其他蚜虫。麦长管蚜(Sitobion Venae)的研究相对广泛，与许多其他研究的麦长管蚜物种相比，麦长管蚜具有更多的共生体，这为研究麦长管蚜共生群落提供了一个有用的系统。该项目将使用对照实验来研究蚜虫共生体如何改变蚜虫种群动态，从而对生物防治产生影响。目标1.从田间采集的样品中，通过抗生素治疗和微量注射来操纵麦长管蚜体内的微生物群，从而建立一套实验的麦长管蚜-共生菌系。2.确定在受到不同天敌(昆虫病原真菌和寄生蜂)挑战时寄生内共生菌的成本和收益。利用人工群落中隔和田间试验跟踪种群/群落随时间的变化新颖性和时间新颖性最近的一项荟萃分析强调了缺乏关于谷物蚜虫及其细菌共生体的物种特有信息，而最近的田间研究表明共生体群落对田间管理和丰富的天敌做出了强烈的反应。我们已建立的研究系统使用了广泛的天敌和抑制蚜虫的根际细菌，并有广泛的机会创建人工群落，以跟踪蚜虫-共生系的种群/群落动态。

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.