Evolution of drug-tolerant nematode populations in response to density reduction

Resistance to xenobiotics remains a pressing issue in parasite treatment and global agriculture. Multiple factors may affect the evolution of resistance, including interactions between life-history traits and the strength of selection imposed by different drug-doses. We experimentally created replicate selection lines of free-living Caenorhabditis remanei exposed to Ivermectin at high and low doses to assess whether survivorship of lines selected in drug-treated environments increased, and if this varied with dose. Additionally, we maintained lines where mortality was imposed randomly to control for differences in density between drug-treatments and to distinguish between the evolutionary consequences of drug-treatment vs ecological processes due to changes in density-dependent feedback. After 10 generations we exposed all of the selected lines to high-dose, low-dose and drug-free environments to evaluate evolutionary changes in survivorship as well as any costs to adaptation. Both adul...外源性化学物（xenobiotics）抗性仍是寄生虫治疗与全球农业领域亟待破解的关键难题。诸多因素可影响抗性的演化进程，其中包括生命史性状间的相互作用，以及不同药剂剂量所施加的选择压力强度。本研究通过实验构建了暴露于高、低剂量伊维菌素（Ivermectin）的自由生活雷曼隐杆线虫（Caenorhabditis remanei）重复选择系，以评估经药剂处理环境选育的品系存活率是否得以提升，且该提升效应是否随剂量变化而产生差异。此外，我们还设置了随机施加死亡的对照品系，以控制药剂处理组间的密度差异，并区分药剂处理的演化效应与密度依赖反馈变化所引发的生态过程效应。传代至第10代后，我们将所有选育品系分别暴露于高剂量、低剂量及无药剂环境中，以评估其存活率的演化变化，以及适应过程所可能存在的适合度代价。两类成虫……