Food quality effetcs on parasite-host interactions

关键资源的可获得性可能会显著影响寄生虫与宿主的相互作用。基本膳食资源的低可获得性可能损害宿主的健康，从而增加其对病原体感染的易感性(免疫防御能力降低)。或者，缺乏必需资源的饮食供应可能会损害宿主和寄生虫的适合性，因为资源有限的宿主可能会为寄生虫提供更少的资源(竞争)。本项目的目的是评估必需脂类(多不饱和脂肪酸、甾醇)的可获得性如何影响宿主大型水蚤与其细菌和微孢子虫寄生虫之间的相互作用。为此，将对感染和未感染的大型浮萍进行生活史实验，这些大型浮游动物以脂肪缺乏的藻类为食，并补充单一脂肪酸或甾醇。食物质量对寄主性能的影响将通过比较感染和未感染宿主的健康参数来评估；食物质量对寄生虫性能的影响将通过确定感染的效率和强度来评估。该项目取得的成果将有助于我们了解疫情发生的时间、对人口动态的相关后果以及寄生虫-宿主系统的演变。

The availability of essential resources may significantly affect parasite–host interactions. A low availability of essential dietary resources may impair the fitness of the host thereby increasing its susceptibility to pathogenic infections (reduced immune defences). Alternatively, a low dietary provisioning with essential resources may impair the fitness of host and parasite, because resource–limited hosts may provide less resources for the parasite (competition). The objective of this project is to assess how the availability of essential lipids (polyunsaturated fatty acids, sterols) affects interactions between the host Daphnia magna and its bacterial and microsporidian parasites. For this purpose, life history experiments will be conducted with infected and uninfected D. magna feeding on lipid deficient algae supplemented with single fatty acids or sterols. Effects of food quality on host performance will be assessed by comparing fitness parameters of infected and uninfected hosts; effects of food quality on parasite performance will be assessed by determining the efficiency and intensity of infection. Results obtained in this project will contribute to our understanding of the timing of epidemics, associated consequences for population dynamics, and the evolution of parasite–host systems.