Data from: The association of feeding behavior with the resistance and tolerance to parasites in recently diverged sticklebacks

Divergent natural selection regimes can contribute to adaptive population divergence, but can be sensitive to human-mediated environmental change. Nutrient loading of aquatic ecosystems, for example, might modify selection pressures by altering the abundance and distribution of resources and the prevalence and infectivity of parasites. Here, we used a mesocosm experiment to test for interactive effects of nutrient loading and parasitism on host condition and feeding ecology. Specifically, we investigated whether the common fish parasite Gyrodactylus sp. differentially affected recently diverged lake and stream ecotypes of three-spined stickleback (Gasterosteus aculeatus). We found that the stream ecotype had a higher resistance to Gyrodactylus sp. infections than the lake ecotype, and that both ecotypes experienced a cost of parasitism, indicated by negative relationships between parasite load and both stomach fullness and body condition. Overall, our results suggest that in the early stages of adaptive population divergence of hosts, parasites can affect host resistance, body condition, and diet.

趋异自然选择模式可推动适应性种群分化，但极易受到人类活动介导的环境变化的影响。例如，水生生态系统的营养负荷可通过改变资源的丰度与分布、寄生虫的流行率及感染能力，进而调整选择压力。本研究借助中型生态箱实验（mesocosm experiment），探究营养负荷与寄生作用对宿主体况及摄食生态的交互效应。具体而言，本研究针对常见鱼类寄生虫三代虫属（Gyrodactylus sp.）是否会对近期分化的三刺棘鱼（Gasterosteus aculeatus）的湖泊生态型与溪流生态型产生差异化影响展开了探究。研究结果显示，溪流生态型对三代虫属感染的抗性显著高于湖泊生态型；且两种生态型均承受了寄生代价——寄生虫负载量与胃饱满度、体况均呈显著负相关，这一结果印证了寄生代价的存在。综上，本研究结果表明，在宿主适应性种群分化的早期阶段，寄生虫可对宿主的抗性、体况及摄食策略产生影响。