The aphid microbiome: ecological and evolutionary dynamics of multispecies interactions

所有生物都面临着众多的环境威胁，必须适应以克服这些挑战。许多昆虫从一个意想不到的来源获得帮助-生活在它们体内的细菌共生体。这些内共生体可以对宿主的生物学产生重大影响，从允许宿主昆虫以不平衡的饮食为食，到保护它免受极端温度的影响，以及防止天敌攻击后死亡。在适当的条件下，新获得的共生体可以在昆虫种群中迅速传播，并改变昆虫与其他物种和环境的相互作用。这可能会产生广泛的影响，特别是如果宿主昆虫是农业害虫或疾病的媒介。通常一个宿主携带一种以上的共生体，在这些混合感染中，一种共生体的存在可以改变另一种共生体的生态效应。混合感染对宿主来说也是昂贵的，因为几种共生体可能比一种共生体消耗更多的资源。有证据表明，混合感染比单一共生体感染更不稳定，但对混合感染的长期影响知之甚少。在这个项目中，我们将使用豌豆蚜虫Acyrthosiphon pisum，其中已知有七种共生体。这些共生体中的几种的表型效应被很好地表征，这使我们能够对混合感染的动力学和组成做出具体的预测。学生将进行实验进化实验，以研究不同的环境条件如何影响共生体之间的竞争结果，这不仅可能影响宿主，而且可能影响相互作用的物种。例如，如果一个共生体提供抵抗天敌的能力，由于宿主内的竞争而丧失，天敌将受益。实验进化实验之后将进行基因组分析，以确定参与混合感染中细菌相互作用和为宿主提供生态效益的候选基因和途径。因此，学生将有机会研究共生关系的维持机制及其生态后果，并将接受广泛的昆虫学，基因组学和生物信息学技术。FindaPhD网站的关键词生态与保护

All organisms face a multitude of environmental threats and have to adapt to overcome these challenges. Many insects get help from an unexpected source -bacterial symbionts that live inside their bodies. These endosymbionts can have major effects on their host's biology, from allowing the host insect to feed on unbalanced diets, to protecting it from extreme temperatures and preventing death after attack by natural enemies. Under suitable conditions, a newly acquired symbiont can rapidly spread through an insect population and alter the insects' interactions with other species and the environment. This can potentially have wide-reaching consequences, particularly if the host insect is an agricultural pest or a vector of disease.Very often a host carries more than one symbiont species and in these coinfections, the presence of one symbiont can alter the ecological effects of another. Coinfections can also be costly to the host as several species of symbionts are likely to consume more resources than one.There is some evidence that coinfections are less stable than infections with single symbionts, but very little is known about the long-term effects of coinfections.In this project, we will use the pea aphid, Acyrthosiphon pisum, where seven species of symbionts are known. The phenotypic effects of several of these symbionts are well characterized, which allows us to make specific predictions about the dynamics and composition of coinfections.The student will conduct experimental evolution experiments to investigate how different environmental conditions will affect the outcome of competition between symbionts, which has the potential to not only affect the host but also to affect interacting species. For example if a symbiont that is providing resistance to a natural enemy is lost due to within host competition the natural enemy will benefit. The experimental evolution experiments will be followed by genomic analyses to identify candidate genes and pathways that are involved in bacterial interactions in coinfections and in providing ecological benefits to thehost.The student will therefore have the opportunity to study the mechanisms of the maintenance of a symbiosis and of its ecological consequences and will be trained in a wide range of entomological, genomic and bioinformatics techniques.Keywords for FindaPhD site Ecology & Conservation