Data from: The role of the environment on the evolution of tolerance and resistance to a pathogen

Defense against parasites can be divided into resistance, which limits parasite burden, and tolerance, which reduces pathogenesis at a given parasite burden. Distinguishing between the two and understanding which defense is favored by evolution in different ecological settings are important, for they lead to fundamentally different evolutionary trajectories of host-parasite interactions. We let the mosquito Aedes aegypti evolve under different food levels and either with no parasite, with a constant parasite, or with a coevolving parasite (the microsporidian Vavraia culicis). We then tested tolerance and resistance of the evolved lines on a population level at the two food levels. Exposure to parasites during evolution increased resistance and tolerance, but there were no differences between the lines evolved with coevolving or constant parasites. Mosquitoes that had evolved with food restriction had higher resistance than those evolved with high food, but similar tolerance. The mosquitoes that had restricted food when being tested had lower tolerance than those with normal food, but there was no difference in resistance. Our results emphasize the complexity and dependence on environmental conditions of the evolution and expression of resistance and tolerance, and help to evaluate some of the predictions about the evolution of host defense against parasites.宿主抗寄生虫防御可分为两类：抗性（resistance），即限制寄生虫负荷；以及耐受性（tolerance），即在既定寄生虫负荷下降低致病作用。区分这两种防御策略，并明确不同生态环境中演化青睐何种防御方式，具有重要意义——二者会导致宿主-寄生虫互作的演化轨迹产生根本性差异。 我们让埃及伊蚊（Aedes aegypti）在不同食物水平下开展演化实验，实验分组分别为无寄生虫感染组、持续寄生虫感染组，以及共演化寄生虫感染组（该寄生虫为微孢子虫Vavraia culicis）。随后我们在两种食物水平下，于种群层面检测了各演化株系的耐受性与抗性。 演化过程中接触寄生虫可提升抗性与耐受性，但共演化寄生虫组与持续寄生虫组的演化株系之间并无显著差异。在限食条件下演化的埃及伊蚊，其抗性高于高食物条件下演化的个体，但二者耐受性相近。 检测时处于限食条件的埃及伊蚊，其耐受性低于正常喂食条件的个体，但二者抗性无显著差异。 本研究结果凸显了抗性与耐受性的演化及表达的复杂性，以及其对环境条件的依赖性，同时有助于验证关于宿主抗寄生虫防御演化的若干预测。