Glyphosate’s primary metabolite, AMPA (aminomethylphosphonic acid), is one of the most widely detected anthropogenic substance in surface waters worldwide. However, ecotoxicological studies on the potential effects of this metabolite at environmental concentrations on wildlife are scarce. Yet, due to its chemical properties, AMPA is likely to affect non-target species. In this study, we investigated sublethal effects of environmental concentrations of AMPA on the larval development of a widespread amphibian species, the spined toad Bufo spinosus. We performed a factorial experiment to study the effect of concentration and the timing of exposure (during embryonic development, larval development or both) to AMPA on the morphology, rate of development and survival of tadpoles. AMPA and timing of exposure interactively affected tadpole size (individuals exposed to AMPA after hatching were transitorily smaller, while individuals exposed to AMPA before hatching were longer), but not duration of development. Most of these effects were linked to exposure during embryonic development. Such effects in individuals exposed during embryonic development solely were long-lasting and persisted until the latest larval stages. Finally, we found that exposure to AMPA after hatching (during the larval stage) increased mortality. Exposure to low environmental concentrations of AMPA could have long-lasting consequences on fitness and population persistence. These findings are especially important to take into account at a time when multiple threats can interact to affect wildlife.

草甘膦的主要代谢物 AMPA（氨甲基膦酸）是全球地表水中检测最广泛的人为物质之一。然而，关于这种代谢物在环境浓度下对野生动物的潜在影响的生态毒理学研究很少。然而，由于其化学特性，AMPA 可能会影响非目标物种。在这项研究中，我们研究了环境浓度的 AMPA 对广泛分布的两栖动物物种——棘蟾蜍（Bufo spinosus）幼虫发育的亚致死影响。我们进行了析因实验来研究 AMPA 的浓度和暴露时间（在胚胎发育、幼虫发育或两者期间）对蝌蚪形态、发育速率和存活的影响。AMPA 和暴露时间交互影响蝌蚪的大小（孵化后暴露于 AMPA 的个体暂时较小，而孵化前暴露于 AMPA 的个体较长），但不影响发育持续时间。这些影响大部分与胚胎发育期间的暴露有关。对于仅在胚胎发育期间暴露的个体来说，这种影响是长期持续的，并持续到最后的幼虫阶段。最后，我们发现孵化后（幼虫阶段）暴露于 AMPA 会增加死亡率。暴露于环境中低浓度的 AMPA 可能会对健康和种群持久性产生长期影响。在多种威胁相互作用影响野生动物的时候，考虑这些发现尤其重要。