Jonathan Mui Rose Hills
The Effect of Lighting on Glucocorticoid Levels in Ctenomys sociabilis
Ambient light is essential to a wide variety of biological processes, including behavior, reproduction, and physiology. Accordingly, changes in ambient lighting may induce stress and thereby affect the health of an animal. Analysis of glucocorticoid (GC) hormones, the hormones that help mediate stress responses provides an important means of evaluating such effects. GCs increase blood glucose levels and stimulate glucose production to provide energy for the flight or fight response to stressors. My project seeks to understand how GC levels in colonial tuco-tucos (Ctenomys sociabilis) vary in response to different ambient light conditions, as well as how variation in glucose levels tracks acute stress (GC) responses. In the wild, these subterranean rodents spend the majority of their time in dark tunnels; in the lab, the animals are exposed to constant light during the daytime. By comparing GC and blood glucose levels in animals housed in clear versus red plastic caging, I will evaluate the effects of different lighting regimes on physiological measures of stress. This research has implications for (1) understanding the effects of ambient light on stress physiology; (2) the ability for blood glucose to be used as an indicator of acute stress; and (3) the need for species-appropriate light environments in animal facilities.