The ecology of host-pathogen interactions in Lepidoptera

了解是什么影响了特定物种的密度和分布，对于我们管理生物多样性和制定保护作物和人类种群的可持续方法至关重要。病原体是所有生态系统中的关键组成部分。我们知道病原体可以对生存产生重大影响，但人们对它们在动物种群中的作用以及对群落结构的影响知之甚少。这个项目关注的是一组病原体，杆状病毒，这种病毒在几类昆虫中很常见，也被开发成害虫控制剂。我们正在使用两个模型系统来研究病毒感染；西部帐篷毛虫，加州雨生软毛虫和卷心菜环毛虫，Ni。初夏，人们经常在落叶树上看到帐篷毛虫，当它们的数量很多时，它们往往会被一种攻击毛毛虫阶段的杆状病毒杀死。卷心菜环纹夜蛾是一种以油菜为食的物种，每年迁徙到加拿大，是大田和温室作物的主要害虫。利用这两个系统，我们将确定决定抗虫性和病原菌毒力的因素，并探索遗传变异在寄主-病原菌相互作用中的作用。我们的目标是了解昆虫的饮食对疾病的易感性是如何影响的；例如，昆虫对某些植物物种更脆弱吗？我们知道这些病毒在遗传上是可变的，我们想了解这是如何影响它们与宿主的互动的。我们怀疑，涉及许多基因毒株的病毒感染更具致病性。我们想在自然人口中测试这一想法。这项研究的独特之处在于，它使用了来自空间上分离的、定期经历高水平感染的宿主群体的长期数据。这些结果将具有广泛的意义，因为了解影响杆状病毒生态和进化的因素可以指导改进害虫控制计划的发展。总体而言，这些研究的见解将确定哪些成分影响寄主抗性和病原菌毒力的变化，遗传多样性如何影响疾病严重程度，以及环境因素对调节疾病风险的影响。

Understanding what influences the density and distribution of a particular species is fundamental to our ability to manage biodiversity and to develop sustainable methods for protecting crops and human populations. Pathogens are key components in all ecosystems. We know that pathogens can have major impacts on survival but their roles in animal populations and impacts on community structure are poorly understood. This program focuses on one group of pathogens, the baculoviruses, which are common in several groups of insects, and also have been developed as pest control agents. We are using two model systems for the study of viral infection; the western tent caterpillar, Malacosoma californicum pluviale and the cabbage looper, Trichoplusia ni. Tent caterpillars are often seen on deciduous trees in early summer and when their numbers are high they are often killed by a baculovirus which attacks the caterpillar stage. The cabbage looper is a brassica-feeding species which migrates into Canada each year and can be a major pest on both field and greenhouse crops. Using these two systems we will identify the factors that determine insect resistance and pathogen virulence and explore the role of genetic variation in host-pathogen interactions. Our goal is to understand how susceptibility to disease is influenced by an insect's diet; e.g. are insects more vulnerable on certain plant species? We know that the viruses are genetically variable, and we want to understand how this affects their interactions with the host. We suspect that virus infections involving many genetic strains are more pathogenic. We want to test this idea in a natural population. This study is unique in that it uses information from long-term data from spatially separated host populations that periodically experience high levels of infection. These results will have broad implications in that understanding the factors that influence baculovirus ecology and evolution could guide to the development of improved insect pest control programs. Overall, insights from these studies will identify what components influence changes in host resistance and pathogen virulence, how genetic diversity influences disease severity, and the influence of the environmental factors on modulating the risk of disease risk.