Artificial Light At Night (ALAN) is an environmental stressor that can disrupt individual physiology and ecological interactions. Hormones such as corticosterone are often responsible for mediating an organism’s response to environmental stressors. We investigated whether ALAN was associated with a corticosterone response and whether it exacerbated the effects of another common stressor, predation. We tested for consumptive, non-consumptive, and physiological effects of ALAN and predator presence (dragonfly larvae) on a widespread amphibian, the American toad (Anaxyrus americanus). We found predators had consumptive (decreased survival) and non-consumptive (decreased growth) effects on larval toads. ALAN did not affect larval toads nor did it interact with the predator treatment to increase larval toad predation. Despite the consumptive and non-consumptive effects of predators, neither predators nor ALAN affected corticosterone concentration in the larval and metamorph life-stages. In contrast to studies in other organisms, we did not find any evidence that suggested ALAN alters predator–prey interactions between dragonfly larvae and toads. However, there was an inverse relationship between corticosterone and survival that was exacerbated by exposure to ALAN when predators were absent. Additionally, larval-stage exposure to ALAN increased corticosterone concentration in juvenile toads. Our results suggest the physiological effects of ALAN may not be demonstrated until later life-stages.

夜间人造光（ALAN）是一种环境压力源，可以破坏个体的生理和生态相互作用。激素（例如皮质酮）通常负责介导生物体对环境压力的响应。我们调查了ALAN是否与皮质酮反应有关，以及它是否加剧了另一种常见应激源掠食的影响。我们测试了ALAN和捕食者的存在（蜻蜓幼虫）对广泛的两栖类美洲蟾蜍（American Anastyrus americanus）的食用，非食用和生理作用）。我们发现捕食者对幼虫蟾蜍具有消耗性（存活率降低）和非消耗性（生长率降低）影响。ALAN既不影响幼虫蟾蜍，也不与捕食者治疗相互作用以增加幼虫蟾蜍的捕食。尽管捕食者具有消费和非消费效应，但捕食者和ALAN均未影响幼虫和变态生命阶段皮质酮的浓度。与其他生物的研究相反，我们没有发现任何证据表明ALAN会改变蜻蜓幼虫和蟾蜍之间的天敌相互作用。但是，在缺乏掠食者的情况下，暴露于ALAN会加剧皮质酮与生存之间的反比关系。此外，幼虫阶段暴露于ALAN会增加幼年蟾蜍中皮质酮的浓度。