Department of Biology, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44016, USA.
Cleveland Metroparks Zoo, 4200 Wildlife Way, Cleveland, OH 44109, USA; Disney's Animals, Science and Environment, 1200 East Savannah Circle, Bay Lake, FL, USA.
Gen Comp Endocrinol. 2020 Sep 1;295:113508. doi: 10.1016/j.ygcen.2020.113508. Epub 2020 May 19.
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.
人工夜间光照（ALAN）是一种环境胁迫源，可破坏个体生理和生态相互作用。皮质酮等激素通常负责调节生物体对环境胁迫源的反应。我们研究了 ALAN 是否与皮质酮反应有关，以及它是否会加剧另一种常见胁迫源——捕食的影响。我们测试了 ALAN 和捕食者（蜻蜓幼虫）对广泛分布的两栖动物——美洲蟾蜍（Anaxyrus americanus）的消耗性、非消耗性和生理效应。我们发现捕食者对蝌蚪有消耗性（存活率降低）和非消耗性（生长速度降低）的影响。ALAN 既不影响蝌蚪，也不与捕食者处理相互作用以增加蝌蚪的捕食率。尽管捕食者具有消耗性和非消耗性的影响，但无论是捕食者还是 ALAN 都不会影响蝌蚪和变态阶段的皮质酮浓度。与其他生物体的研究不同，我们没有发现任何证据表明 ALAN 改变了蜻蜓幼虫和蟾蜍之间的捕食者-猎物相互作用。然而，当没有捕食者时，皮质酮与存活率之间存在反比关系，而这种关系在暴露于 ALAN 时会加剧。此外，幼虫期暴露于 ALAN 会增加幼蟾蜍的皮质酮浓度。我们的研究结果表明，ALAN 的生理影响可能要到后期生命阶段才会显现。
