Touzot Morgane, Teulier Loïc, Lengagne Thierry, Secondi Jean, Théry Marc, Libourel Paul-Antoine, Guillard Ludovic, Mondy Nathalie
University of Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR5023 LEHNA, Villeurbanne, France.
Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle (MNHN), UMR 7179, Brunoy, France.
Conserv Physiol. 2019 Feb 6;7(1):coz002. doi: 10.1093/conphys/coz002. eCollection 2019.
The presence of artificial light at night (ALAN) is currently a global phenomenon. By altering the photoperiod, ALAN may directly affect the physiology and behaviour of many organisms, such as the timing of daily rhythms, hormonal regulation, food intake, metabolism, migration and reproduction. Surprisingly while it is known that ALAN exposure strongly influences health of humans and laboratory animals, studies on wildlife remain scarce. Amphibians are one of the most nocturnal groups of vertebrates and exhibit an unfavourable conservation status in most parts of the world. In order to gain insight into the consequences of ALAN, we experimentally exposed 36 adult breeding male common toads, , to a light intensity of 0.1, 5 or 20 lux for 20 days, to investigate the activity using infrared cameras and the whole-body oxygen consumption by respirometry, as well as body mass and food intake. ALAN reduced toad activity over 24 h by 56% at 5 lux and by 73% at 20 lux. It did not affect the total energy expenditure but altered energy allocation. Indeed, standard energy expenditure increased by 28% at 5 lux and by 58% at 20 lux, while activity energy expenditure decreased by 18% at 5 lux and 38% at 20 lux. Finally, body mass and food intake were not affected. This study suggests that ALAN plays a large role in the activity and energy metabolism of common toads, which may have a long-term negative effect on the fitness of common toad populations. Generalizing these results to other taxa is crucial for conservation of biodiversity in an increasingly light world.
夜间人造光（ALAN）的存在目前是一种全球现象。通过改变光周期，ALAN可能直接影响许多生物的生理和行为，如日常节律的时间、激素调节、食物摄入、新陈代谢、迁徙和繁殖。令人惊讶的是，虽然已知暴露于ALAN会强烈影响人类和实验动物的健康，但关于野生动物的研究仍然很少。两栖动物是最夜行性的脊椎动物群体之一，在世界大部分地区都处于不利的保护状态。为了深入了解ALAN的影响，我们将36只成年繁殖雄性普通蟾蜍实验性地暴露于0.1、5或20勒克斯的光照强度下20天，使用红外摄像机研究其活动情况，并通过呼吸测定法测量其全身耗氧量，以及体重和食物摄入量。ALAN使蟾蜍在24小时内的活动量在5勒克斯时减少了56%，在20勒克斯时减少了73%。它没有影响总能量消耗，但改变了能量分配。实际上，标准能量消耗在5勒克斯时增加了28%，在20勒克斯时增加了58%，而活动能量消耗在5勒克斯时减少了18%，在20勒克斯时减少了38%。最后，体重和食物摄入量没有受到影响。这项研究表明，ALAN在普通蟾蜍的活动和能量代谢中起着很大作用，这可能对普通蟾蜍种群的适应性产生长期负面影响。将这些结果推广到其他分类群对于在日益明亮的世界中保护生物多样性至关重要。
