Data from: Population divergence in compensatory growth responses and their costs in sticklebacks

Compensatory growth (CG) may be an adaptive mechanism that helps to restore an organisms’ growth trajectory and adult size from deviations caused by early life resource limitation. Yet, few studies have investigated the genetic basis of CG potential and existence of genetically based population differentiation in CG potential. We studied population differentiation, genetic basis, and costs of CG potential in nine-spined sticklebacks (Pungitius pungitius) differing in their normal growth patterns. As selection favors large body size in pond and small body size in marine populations, we expected CG to occur in the pond but not in the marine population. By manipulating feeding conditions (viz. high, low and recovery feeding treatments), we found clear evidence for CG in the pond but not in the marine population, as well as evidence for catch-up growth (i.e., size compensation without growth acceleration) in both populations. In the marine population, overcompensation occurred individuals from the recovery treatment grew eventually larger than those from the high feeding treatment. In both populations, the recovery feeding treatment reduced maturation probability. The recovery feeding treatment also reduced survival probability in the marine but not in the pond population. Analysis of interpopulation hybrids further suggested that both genetic and maternal effects contributed to the population differences in CG. Hence, apart from demonstrating intrinsic costs for recovery growth, both genetic and maternal effects were identified to be important modulators of CG responses. The results provide an evidence for adaptive differentiation in recovery growth potential.

补偿生长（Compensatory Growth, CG）或许是一种适应性机制，可帮助生物体修复因早期资源限制所引发的生长轨迹偏差与成体体型异常。然而，目前学界针对补偿生长潜力的遗传基础，以及该潜力基于遗传的种群分化现象的研究仍较为匮乏。本研究以生长模式存在显著差异的九棘刺鱼（Pungitius pungitius）为实验材料，系统探究了其补偿生长潜力的种群分化特征、遗传基础与潜在适应性代价。鉴于自然选择对淡水池塘种群倾向于保留较大体型，而对海洋种群则倾向于保留较小体型，我们推测池塘种群可表现出补偿生长，而海洋种群则无此能力。通过设置三类摄食处理组（高投喂组、低投喂组与恢复投喂组）开展受控实验，我们明确观测到池塘种群存在补偿生长，而海洋种群未表现出该现象；同时在两个种群中均发现了追赶生长（Catch-up Growth，即未伴随生长加速的体型补偿）。在海洋种群中，还出现了过度补偿现象：恢复投喂组个体的最终体型显著大于高投喂组个体。无论是池塘种群还是海洋种群，恢复投喂处理均会降低个体的成熟概率；此外，恢复投喂还会降低海洋种群的存活率，但对池塘种群的存活率无显著影响。对种群间杂交个体的遗传分析进一步表明，遗传效应与母源效应均对补偿生长的种群差异存在显著贡献。综上，本研究不仅证实了恢复生长存在固有适应性代价，还明确了遗传效应与母源效应均为调控补偿生长响应的关键因子。本研究结果为恢复生长潜力的适应性分化提供了坚实的实验证据。