Meeting Abstract
Artificial light at night (ALAN) is artificial light that alters the natural light dark patterns in ecosystems. ALAN can have a suite of effects on community structure and drive evolutionary processes that influences a range of behavioral and physiological traits. Our understanding of possible effects of ALAN on amphibians is lacking and research is warranted as ALAN could contribute to stress and declines of amphibian populations, particularly in urban areas. I tested the hypothesis that exposure to constant light or pulsed light at night (simulating a motion sensor light) would physiologically stress leopard frog tadpolesRana berlandieri. Using a reaction norm approach, I reared tadpoles under a natural light cycle for 7 days (baseline) and then under either constant light or pulsed ALAN for 14 days (light treatment). Using water-borne hormones, I measured corticosterone (CORT), the main amphibian glucocorticoid, release rates on days 7 and 21. Compared to baseline CORT release rates, tadpoles showed significantly higher CORT release rates after 14 days of constant light while tadpoles showed significantly lower CORT release rates after 14 days under pulsed ALAN. These results suggest that short-term exposure to constant or pulsed light at night contribute to stress in tadpoles, albeit differently, with constant light inducing CORT production while pulsed ALAN is downregulating CORT production. Further investigation is needed to explore long-term effects of exposure to ALAN, as long-term exposure may lead to chronic stress or tadpoles may habituate to ALAN, and possible carry over effects, as juvenile growth and survival may be affected by exposure to ALAN in the larval stage. Based on our current findings, mitigation of exposure to ALAN should be considered in management and conservation plans for amphibians.
