Meeting Abstract
Temperatures have been rising due to climate change and other anthropogenic changes have been altering the environment. Increased temperatures and other environmental changes may affect an organism’s ability to maintain homeostasis. Monitoring physiological responses to stressors in individuals can provide an early-warning indicator of stressed populations. During early development in amphibians, changing conditions can increase stress, affecting developmental rate and fitness. Temperature changes can decrease immunity in amphibians. Further, stressed amphibians release corticosterone (CORT) into water and can uptake exogenous CORT. We compared the effects of temperature and the addition of exogenous CORT on the stress response and body condition of Rana berlandieri tadpoles across 4 treatments: 1) 19°C with no CORT, 2) 19°C with 125nM exogenous CORT, 3) 27°C with no CORT, and 4) 27°C with 125nM exogenous CORT. We used a water-borne hormone assay to measure CORT release rates after 7 days in each treatment. We found that tadpoles exposed to higher temperatures had reduced body condition compared to the control, but the addition of exogenous CORT did not affect body condition. We also found that both temperature and the addition of exogenous CORT affected CORT release rates. Our results indicate that both temperature and exogenous CORT induce physiological stress in Rana berlandieri. CORT in and of itself is not likely mediating the decline in body condition. These results indicate that changing environmental variables may result in multiple stressors and could lead to reduced population viability. Monitoring physiological responses to multiple stressors will be key to understanding mechanisms underlying the response to environmental change and predicting its effects across populations.
