Artificial light at night (ALAN) is recognized as one of the major anthropogenic pollutants jeopardizing biodiversity at a global scale. Few studies have focused on the impacts of nocturnal light on freshwater ecosystems despite their increasing exposure to light pollution worldwide due to human activities along rivers or lakes. By modifying metabolism, the disruption of natural light regime could modify the leaf palatability and affect the plant-herbivore interactions which can partly determine the structure of macrophyte communities. By experimentally mimicking light conditions from sub-urban areas, we measured the effects of low-level light at night on the leaf traits of an aquatic plant, Ceratophyllum demersum, and herbivory by the snail Lymnaea stagnalis, a generalist feeder. We demonstrate that artificial light at night increases the herbivory rate: leaves of C. demersum that had been exposed to ALAN for three months were 1.6 times more consumed by L. stagnalis than control leaves. The increase in C. demersum palatability to the pond snail when plants were exposed to ALAN was not due to a decrease in dry matter content or to a modification of the biomechanical characteristics of the leaves. Because snails have not been exposed to nocturnal light before or during the herbivory experiment, this increase in leaf palatability, is possibly linked to modifications of primary and/or secondary metabolism. Our results suggest that ALAN is a potential key factor affecting ecological processes in aquatic ecosystems such as trophic networks.

夜间人造光 (ALAN) 被认为是在全球范围内危害生物多样性的主要人为污染物之一。尽管由于人类沿河流或湖泊的活动，淡水生态系统在全球范围内日益受到光污染的影响，但很少有研究关注夜间光照对淡水生态系统的影响。通过改变新陈代谢，自然光照条件的破坏可以改变叶子的适口性并影响植物 - 食草动物的相互作用，这可以部分决定大型植物群落的结构。通过实验模拟郊区的光照条件，我们测量了夜间低强度光照对水生植物Ceratophyllum demersum和草食性蜗牛Lymnaea stagnalis的叶子特征的影响，一个多面手。我们证明夜间人造光会增加食草率：暴露于 ALAN 三个月的C. demersum叶子被 L. stagnalis消耗的量是对照叶子的1.6 倍。C. demersum的增加当植物暴露于 ALAN 时，池塘蜗牛的适口性不是由于干物质含量的减少或叶子的生物力学特性的改变。由于蜗牛在食草实验之前或期间没有暴露于夜间光线下，叶子适口性的这种增加可能与初级和/或次级代谢的改变有关。我们的研究结果表明，ALAN 是影响水生生态系统（如营养网络）生态过程的潜在关键因素。