Artificial Light At Night (ALAN) is an emerging pollution, that dramatically keeps on increasing worldwide due to urbanisation and transport infrastructure development. In 2016, it nearly affected 23% of the Earth's surface. To date, all terrestrial and aquatic ecosystems have been affected. The disruption of natural light cycles due to ALAN is particularly expected for nocturnal species, which require dark periods to forage, move, and reproduce. Apart from chiropterans, amphibians contain the largest proportion of nocturnal species among vertebrates exhibiting an unfavourable conservation status in most parts of the world and living in ALAN polluted areas. Despite the growing number of studies on this subject, our knowledge on the direct influence of nocturnal lighting on amphibians is still scarce. To better understand the consequences of ALAN on the breeding component of amphibian fitness, we experimentally exposed male breeding common toads (Bufo bufo) to ecologically relevant light intensities of 0.01 (control), 0.1 or 5 lux for 12 days. At mating, exposed males took longer than controls to form an amplexus, i.e. to pair with a female, and broke amplexus before egg laying, while controls never did. These behavioural changes were associated with fitness alteration. The fertilisation rate of 5 lux-exposed males was reduced by 25%. Salivary testosterone, which is usually correlated with reproductive behaviours, was not altered by ALAN. Our study demonstrates that ALAN can affect the breeding behaviour of anuran species and reduce one component of their fitness. Given the growing importance of ALAN, more work is needed to understand its long-term consequences on the behaviour and physiology of individuals. It appears essential to identify deleterious effects for animal populations and propose appropriate management solutions in an increasingly brighter world.

夜间人工光（ALAN）是一种新兴污染，由于城市化和交通基础设施的发展，其在世界范围内的污染持续急剧增加。2016年，它几乎影响了地球23％的表面。迄今为止，所有陆地和水生生态系统均受到影响。夜间物种特别期望由于ALAN引起的自然光循环中断，这需要黑暗时期进行觅食，移动和繁殖。除鳞翅目动物外，两栖动物中夜间活动物种的比例最大，在世界大多数地区表现出不利的保护地位并生活在ALAN污染地区的脊椎动物中。尽管对此问题的研究越来越多，但我们对夜间照明对两栖动物的直接影响的了解仍然很少。将Bufo bufo）置于生态相关的0.01（对照），0.1或5 lux的光强度下，持续12天。交配时，雄性雄性花比对照组更长的时间形成丛状，即与雌性配对，并在产卵前弄断了神经痛，而对照组则没有。这些行为改变与适应性改变有关。5名暴露于勒克斯的雄性的受精率降低了25％。唾液睾丸激素通常与生殖行为有关，但ALAN并未改变。我们的研究表明，ALAN可以影响无脊椎动物的繁殖行为并降低其适应性的一个组成部分。鉴于ALAN的重要性越来越高，需要做更多的工作来了解ALAN对个人行为和生理的长期影响。在日益光明的世界中，确定对动物种群的有害影响并提出适当的管理解决方案似乎至关重要。