Water contamination poses an important challenge to aquatic fauna, including well-documented effects on amphibian larvae. However, little is known about how contamination during the larval stages may affect post-metamorphic phases, or whether resistance may have evolved in some populations. In this work, we tested the hypothesis that chronic exposure to ammonium (a common contaminant in agroecosystems with confirmed effects on anuran tadpoles) during the larval stage of Pelophylax perezi frogs would affect growth and locomotor performance of metamorph, juvenile, subadult and adult stages. We also predicted that the effects of ammonium would be milder in offspring originated from parental agroecosystem frogs than those originating from forests. We compared tadpoles from both habitats either reared in untreated water or chronically exposed to ammonium. We found that exposure to ammonium during the larval stage inflicted effects on morphology (different measures of body size) and swimming speed after metamorphosis until adulthood. However, these effects were not always consistent through post-metamorphic stages and the effects differed as a function of treatment and habitat. In adults, body size and condition were greater in non-ammonium and ammonium exposed individuals, respectively. These differences were not detectable in metamorphs, for which only ammonium-exposed individuals from agroecosystem showed reduced body size in intermediate post-metamorphic stages. In turn, treatment reduced jumping distance only in agroecosystem adults, subadults and juveniles, which was opposite to the trend observed just after metamorphosis. These changes of patterns throughout the ontogeny of P. perezi could be due to processes such as compensatory growth, delayed energy costs derived from it, or early sexual differences that could be present even before they can be accounted for. In summary, this study suggests that exposure to ammonium during larval stages can result in diverse biological and long-term outcomes in later life stages.

水污染对水生动物群构成了重大挑战，包括对两栖动物幼虫的有据可查的影响。然而，关于幼虫阶段的污染如何影响变质后阶段，或者在某些种群中是否已经进化出抗性，我们知之甚少。在这项工作中，我们检验了在Pelophylax perezi幼虫阶段长期暴露于铵（农业生态系统中的一种常见污染物，对 anuran 蝌蚪有确认的影响）的假设青蛙会影响变态、幼年、亚成年和成年阶段的生长和运动表现。我们还预测，铵对来自亲本农业生态系统青蛙的后代的影响会比来自森林的后代更温和。我们比较了两种栖息地的蝌蚪，它们要么在未经处理的水中饲养，要么长期暴露于铵中。我们发现，在幼虫阶段暴露于铵会对形态（体型大小的不同测量）和变态后直至成年的游泳速度产生影响。然而，这些影响在变质后阶段并不总是一致的，并且这些影响因处理和栖息地的不同而不同。在成年人中，非铵和铵暴露个体的体型和状况分别更大。这些差异在变质体中没有检测到，只有农业生态系统中暴露于铵的个体在变质后的中间阶段显示出体型减小。反过来，处理仅减少了农业生态系统成人、亚成人和青少年的跳跃距离，这与刚变态后观察到的趋势相反。这些模式在整个个体发育过程中的变化P. perezi可能是由于补偿性生长、由此产生的延迟能量成本或早期性别差异等过程造成的，这些差异甚至在它们被解释之前就可能存在。总之，这项研究表明，在幼虫阶段暴露于铵可导致后期生命阶段的各种生物学和长期结果。