Analysis code from Inconsistent evolution and growth-survival tradeoffs in <i>Gambusia affinis</i>

Growth-survival tradeoffs may be a generalizable mechanism influencing trajectories of prey evolution. Here, we investigate evolutionary contributions to growth and survival in western mosquitofish (<i>Gambusia affinis</i>) from 10 populations from high- and low-predation ancestral environments. We assess (i) the degree to which evolutionary components of growth and survival are consistent or inconsistent across populations within ancestral predation environments, and (ii) whether growth and survival tradeoff at the population level. We measure growth and survival on groups of common-reared mosquitofish in pond mesocosms. We find that evolution of growth is consistent, with fish from low-predation ancestral environments showing higher growth, while the evolution of survival is inconsistent, with significant population-level divergence unrelated to ancestral predation environment. Such inconsistency prevents a growth-survival tradeoff across populations. Thus, the generalizability of contemporary evolution likely depends on local context of evolutionary tradeoffs, and a continued focus on singular selective agents (e.g. predators) without such local context will impede insights into generalizable evolutionary patterns.生长-存活权衡（growth-survival tradeoffs）或许是影响猎物演化轨迹的普适性机制。本研究以来自高捕食压力与低捕食压力祖先环境的10个西部食蚊鱼（*Gambusia affinis*）种群为研究对象，探究其生长与存活的演化贡献。我们从两方面开展评估：（i）在祖先捕食环境范畴内，生长与存活的演化组分在不同种群间是否具有一致性；（ii）种群水平上是否存在生长-存活权衡。我们通过池塘中宇宙（pond mesocosms）实验，对共同饲养的食蚊鱼群体的生长与存活情况进行测定。研究结果显示，生长的演化模式具有一致性：源自低捕食压力祖先环境的个体生长速率更高；而存活的演化模式则不具备一致性，种群间存在显著分化，但该分化与祖先捕食环境并无关联。这种不一致性导致种群间未出现生长-存活权衡现象。综上，当代演化的普适性可能依赖于演化权衡所处的局部环境背景；若仅聚焦单一选择因子（如捕食者）而忽视此类局部环境背景，将阻碍我们对普适性演化模式的深入认知。