Tyson Research Center, Washington University in St Louis, 6750 Tyson Valley Road, Eureka, MO 63025, USA.
Parasitology. 2019 Nov;146(13):1665-1672. doi: 10.1017/S0031182019000994. Epub 2019 Aug 29.
Host condition depends in large part on the quality and quantity of available food and heavily influences the outcome of parasite infection. Although parasite fitness traits such as growth rate and size may depend on host condition, whether host food quality or quantity is more important to parasite fitness and within-host interactions is poorly understood. We provided individual mosquito hosts with a standard dose of a gregarine parasite and reared mosquitoes on two food types of different quality and two quantities. We measured host size, total parasite count and area, and average size of parasites within each treatment. Food quality significantly influenced the number of parasites in a host; hosts fed a low-quality diet were infected with more parasites than those provided a high-quality diet. In addition, we found evidence of within-host competition; there was a negative relationship between parasite size and count though this relationship was dependent on host food quality. Host food quantity significantly affected total parasite area and parasite size; lower food quantity resulted in smaller parasites and reduced overall parasite area inside the host. Thus both food quality and quantity have the potential to influence parasite fitness and population dynamics.
宿主状况在很大程度上取决于可用食物的质量和数量，并严重影响寄生虫感染的结果。尽管寄生虫的适应特征，如增长率和大小，可能取决于宿主状况，但宿主食物质量或数量对寄生虫适应性和体内相互作用更为重要，这一点知之甚少。我们为个体蚊子宿主提供了标准剂量的沙雷氏菌寄生虫，并在两种不同质量和两种数量的食物类型上饲养蚊子。我们测量了每个处理组的宿主大小、总寄生虫数和面积，以及寄生虫的平均大小。食物质量显著影响宿主中的寄生虫数量；与提供高质量饮食的宿主相比，低质量饮食的宿主感染的寄生虫更多。此外，我们发现了体内竞争的证据；尽管这种关系取决于宿主食物质量，但寄生虫大小和数量之间存在负相关关系。宿主食物数量显著影响总寄生虫面积和寄生虫大小；食物数量较少会导致寄生虫较小，宿主内的总寄生虫面积减少。因此，食物质量和数量都有可能影响寄生虫适应性和种群动态。
