Forsburg Zachery R, Guzman Alex, Gabor Caitlin R
Department of Biology, Texas State University, San Marcos, TX, 78666, USA.
Department of Biology, Texas State University, San Marcos, TX, 78666, USA.
Environ Pollut. 2021 May 15;277:116775. doi: 10.1016/j.envpol.2021.116775. Epub 2021 Feb 18.
Artificial light at night (ALAN) alters the natural light dark patterns in ecosystems. ALAN can have a suite of effects on community structure and is a driver of evolutionary processes that influences a range of behavioral and physiological traits. Our understanding of possible effects of ALAN across species amphibians is lacking and research is warranted as ALAN could contribute to stress and declines of amphibian populations, particularly in urban areas. We tested the hypothesis that exposure to constant light or pulsed ALAN would physiologically stress Rio Grande leopard frog (Rana berlandieri) and Gulf Coast toad (Bufo valliceps) tadpoles. We reared tadpoles under constant or pulsed (on and off again) ALAN for 14 days and measured corticosterone release rates over time using a non-invasive water-borne hormone protocol. ALAN treatments did not affect behavior or growth. Tadpoles of both species had higher corticosterone (cort) release rates after 14 days of constant light exposure. Leopard frog tadpoles had lower cort release rates after exposure to pulsed ALAN while toad tadpoles had higher cort release rates. These results suggest that short-term exposure to constant or pulsed light at night may contribute to stress in tadpoles but that each species differentially modulated their cort response to ALAN exposure and a subsequent stressor. This flexibility in the upregulation and downregulation of hypothalamic-pituitary-interrenal axis response may indicate an alternative mechanism for diminishing the deleterious effects of chronic stress. Nonetheless, ALAN should be considered in management and conservation plans for amphibians.
夜间人造光（ALAN）改变了生态系统中的自然明暗模式。ALAN会对群落结构产生一系列影响，并且是进化过程的驱动因素，影响着一系列行为和生理特征。我们对ALAN对两栖动物物种可能产生的影响缺乏了解，鉴于ALAN可能导致两栖动物种群的应激和数量下降，尤其是在城市地区，因此有必要进行研究。我们检验了这样一个假设，即暴露于持续光照或脉冲式ALAN会使格兰德河豹蛙（Rana berlandieri）和墨西哥湾沿岸蟾蜍（Bufo valliceps）蝌蚪产生生理应激。我们将蝌蚪在持续或脉冲式（开和关交替）ALAN条件下饲养14天，并使用一种非侵入性的水体激素检测方法测量随时间变化的皮质酮释放率。ALAN处理对行为或生长没有影响。两种蝌蚪在持续光照暴露14天后皮质酮（cort）释放率都更高。豹蛙蝌蚪在暴露于脉冲式ALAN后cort释放率较低，而蟾蜍蝌蚪的cort释放率较高。这些结果表明，夜间短期暴露于持续或脉冲式光照可能会导致蝌蚪产生应激，但每个物种对ALAN暴露及随后的应激源的cort反应调节方式不同。下丘脑 - 垂体 - 肾间轴反应上调和下调的这种灵活性可能表明一种减轻慢性应激有害影响的替代机制。尽管如此，在两栖动物的管理和保护计划中应考虑ALAN因素。
