Host-parasite coevolution in complex communities

宿主如何进化以应对传染病的威胁？引起传染病的寄生虫是如何进化来克服宿主防御的？这些都是推动我研究的关键问题，我的研究试图了解宿主和寄生虫之间持续不断的进化之战。研究宿主和寄生虫是如何“共同进化”的，不仅对控制传染病具有重要意义，而且对于回答有关自然界的基本问题也有重要意义。所有活着的生物体都会遭受寄生虫引起的传染病，其中许多疾病会严重影响宿主的健康，甚至可能是致命的。因此，宿主进化出了各种应对寄生虫的方法，从识别和消除微小病原体的复杂而昂贵的免疫系统，到清除外部寄生虫的梳理行为。同样，寄生虫进化出了避免或克服宿主防御的迷人方法(例如，通过分泌抑制免疫反应的蛋白质)，甚至操纵宿主行为以最大限度地传播。宿主和寄生虫存在于多样化的多物种群落中，它们有可能通过对资源的竞争加剧或与投资于防御和反防御特征相关的成本效益权衡的变化来影响它们的进化。例如，捕食可能会减少宿主的可获得性(资源竞争)，从而增加寄生虫的压力，并可能在疾病变得罕见的情况下阻止代价高昂的抵抗机制的演变(权衡)。然而，目前我们对宿主-寄生虫协同进化如何受到更广泛的生态群落(如其他宿主和寄生虫、捕食者、猎物等)的影响知之甚少。本研究计划的目的是了解更广泛生态群落中的物种对宿主和寄生虫进化的影响。为了实现这一点，我将使用数学模型和计算机模拟来揭示影响宿主和寄生虫在其他物种存在时如何共同进化的潜在过程和机制。我还将与经验主义者合作测试新的理论，并使用实验观察来反馈和进一步发展该理论。我将首先通过分析不同的相互作用网络来研究生态群落的结构如何影响共同进化动力学。然后，我将使用我所获得的关于更广泛的生态社区的影响的知识来研究多种宿主和寄生虫特征的共同进化。这将使我能够回答这样的问题：感染多个宿主的寄生虫更有可能是致命的吗？东道主应该在什么时候优先考虑适应性防御而不是先天防御？最后，我将与实验者合作，通过细菌和病毒的共同进化来测试和改进这一理论。我的研究将为基本的生物现象提供关键的见解，例如生物多样性是如何产生和维持的，以及寄生虫在宿主交配行为的进化中扮演的角色。虽然我的工作是理论上的，但它对公共卫生具有重要的影响。例如，病毒可用于治疗抗生素耐药感染(噬菌体疗法)，但了解其他微生物物种的存在如何影响细菌进化以最大限度地提高治疗效果是至关重要的。这对工业和保护也有影响，特别是在预测人类干预或环境变化如何影响自然生态系统或受管理人口的稳定性方面。

How do hosts evolve to cope with the threat of infectious diseases? How do parasites that cause infectious diseases evolve to overcome host defences? These are the key questions that drive my research, which seeks to understand the continual evolutionary battle between hosts and parasites. Studying how host and parasites "co-evolve" not only has important implications for controlling infectious diseases, but also for answering fundamental questions about the natural world.All living organisms suffer from infectious diseases caused by parasites, many of which have a serious impact on host health and can be fatal. As such, hosts have evolved a variety of ways of coping with parasitism, from complex and expensive immune systems that recognise and eliminate microscopic pathogens, to grooming behaviour that removes external parasites. Likewise, parasites have evolved fascinating ways of avoiding or overcoming host defences (e.g. by secreting proteins that suppress immune responses), and even manipulating host behaviour to maximise transmission.Hosts and parasites exist in diverse multi-species communities, which have the potential to impact their evolution through increased competition for resources or changes in cost-benefit trade-offs associated with investing in defence and counter-defence traits. For example, predation may increase pressure on parasites by reducing host availability (resource competition) and may prevent a costly resistance mechanism from evolving if disease becomes rare (trade-offs). However, we currently know very little about how host-parasite coevolution is affected by the wider ecological community (e.g. other hosts and parasites, predators, prey, etc).The aim of this research programme is to understand the impact of species in the wider ecological community on the evolution of hosts and parasites. To achieve this, I will use mathematical models and computer simulations to reveal the underlying processes and mechanisms that affect how hosts and parasites co-evolve in the presence of other species. I will also collaborate with empiricists to test the new theory and use experimental observations to feed back and further develop the theory.I will first investigate how the structure of the ecological community affects co-evolutionary dynamics by analysing different networks of interactions. I will then use the knowledge that I have gained about the impact of the wider ecological community to examine the co-evolution of multiple host and parasite traits. This will allow me to answer questions such as: are parasites that infect multiple hosts more likely to be deadly? And when should hosts prioritise adaptive defences over innate defences? Finally, I will work with experimentalists to test and improve the theory by coevolving bacteria and viruses.My research will provide key insights into fundamental biological phenomena, such as how biodiversity is generated and maintained and the role that parasites play in the evolution of host mating behaviour. Although my work is theoretical, it has important implications for public health. For example, viruses can be used to treat antibiotic resistant infections (phage therapy), but it is crucial to understand how the presence of other microbial species affects bacterial evolution to maximise treatment efficacy. There are consequences for industry and conservation, as well, especially for predicting how human interventions or environmental changes affect the stability of natural ecosystems or managed populations.