Meeting Abstract
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 influence a range of behavioral, developmental, and physiological traits. While ALAN has been shown to alter corticosterone levels of Rana berlandieri tadpoles in a previous laboratory reaction norm study, our understanding of how ALAN affects amphibians in natural environments is lacking, yet research is warranted as ALAN could contribute to stress and declines of amphibian populations, particularly in urban areas. Further, it is unknown if ALAN is interacting with natural environmental stressors such as predator presence. I tested the hypothesis that Rana berlandieri tadpoles exposed to ALAN or the presence of a common predator, dragonfly larvae, will be physiologically stressed and exposure to both ALAN & predators will have additive consequences on corticosterone production and survival. I reared tadpoles in outdoor mesocosms using a 2 X 2 randomized factorial design, with two predator treatments (presence or absence of one caged dragonfly larva), and two light treatments (natural light cycle control or constant ALAN from ~200 LUX LED lights). I measured corticosterone levels using a non-invasive water-borne hormone assay from the tadpoles after 7 and 14 days in treatments and continued to rear tadpoles in treatments until metamorphosis. I also measured and weighed individuals to track growth and development and recorded the date of metamorphosis for each individual. Findings from this study broaden our understanding of anthropogenic factors associated with amphibian declines and based on our current findings, mitigation of exposure to ALAN should be considered in management and conservation plans for amphibians.
