Abstract：
Artificial light at night (ALAN) is a growing environmental problem influencing the fitness of individuals through effects on their physiology and behaviour. Research on animals has primarily focused on effects on behaviour during the night, whereas less is known about effects transferred to daytime. Here, we investigated in the lab the impact of ALAN on the mating behaviour of an ecologically important freshwater amphipod, Gammarus pulex, during both daytime and nighttime. We manipulated the presence of ALAN and the intensity of male-male competition for access to females, and found the impact of ALAN on mating activity to be stronger during daytime than during nighttime, independent of male-male competition. At night, ALAN only reduced the probability of precopula pair formation, while during the daytime, it both decreased general activity and increased the probability of pair separation after pair formation. Thus, ALAN reduced mating success in G. pulex not only directly, through effects on mating behaviour at night, but also indirectly through a carry-over effect on daytime activity and the ability to remain in precopula. These results emphasise the importance of considering delayed effects of ALAN on organisms, including daytime activities that can be more important fitness determinants than nighttime activities.
摘要：
夜间人造光（ALAN）是一个日益严重的环境问题，通过影响其生理和行为来影响个体的健康。对动物的研究主要集中在对夜间行为的影响，而对转移到白天的影响知之甚少。这里,我们在实验室中研究了ALAN对生态重要的淡水两栖动物交配行为的影响，Gammaruspulex,在白天和晚上。我们操纵了ALAN的存在和男性争夺女性的激烈竞争，发现ALAN对交配活动的影响在白天比夜间更强，独立于男性竞争。晚上,艾伦只降低了形成前脉冲对的概率，而在白天，它既降低了一般活性，又增加了配对形成后配对分离的可能性。因此，艾伦不仅直接降低了G.pulex的交配成功率，通过对夜间交配行为的影响，但也间接通过对白天活动的延续效应和保持在前胚层的能力。这些结果强调了考虑ALAN对生物体的延迟效应的重要性，包括比夜间活动更重要的健身决定因素的白天活动。
