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Artificial Light at Night (ALAN) is a pervasive contaminant characterized by the presence of excessive manmade light at times not consistent with the natural day/night cycle. ALAN has several physiological and morphological effects on humans and wildlife, including altering amphibians’ development and skin pigmentation, both of which affect amphibians’ susceptibility to predators and their subsequent fitness. For instance, many amphibians can change their pigmentation to blend in with their surroundings (and hide from predators) through a process called background adaptation. While exposure to ALAN can make tadpoles darker, it is unclear how this pollutant affects background adaptation overall. To test this, I exposed three local species (wood frogs, spring peepers, and American toads) to varied light conditions and background colors for their first weeks of development. I measured tadpoles’ growth and background adaptation abilities by quantifying their skin pigmentation. I found that ALAN and background color both influence growth, although these effects vary by species. Next, I found that wood frog tadpoles were significantly darker when exposed to ALAN versus control light. In contrast, ALAN did not affect spring peeper pigmentation. Lastly, for American toads, I found that ALAN had an interactive effect with background color. In the ALAN treatment but not the control treatment, tadpoles reared in light backgrounds were significantly lighter compared to their surroundings than tadpoles reared in dark backgrounds. This suggests tadpoles’ ability to blend into their rearing background is affected by ALAN. Overall, this project demonstrates the need to further investigate ALAN and similar pollutants.



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Does Artificial Light at Night Influence Amphibian Development and Color Changing Abilities?