Meeting Abstract
Stressful events such as a predator attacks stimulate a multitude of physiological events, including the activation of the hypothalamic-pituitary-adrenal (HPA) axis. The consequential release of glucocorticoids, such as corticosterone, stimulates the mobilization of energy stores for antipredator behavior. When threatened, Rough-skinned Newts (Taricha granulosa) curl up to expose a brightly colored ventral side; a behavior known as the unken reflex. The exposed aposematic coloration warns potential predators of the newts’ toxicity. This study sought to uncover the role of corticosterone and adrenocorticotropic hormone (ACTH) in the unken behavior of Rough-skinned Newts. Newts were injected with corticosterone, ACTH, metyrapone (a corticosterone blocker), and a control (saline). Time in unken was measured and compared to levels of corticosterone in the blood. We found the time in unken was correlated to corticosterone levels for newts given corticosterone injections. However, those given ACTH, metyrapone, and saline had unken times that were not significantly correlated to corticosterone levels in the blood. While there was a large amount of individual variation, corticosterone and ACTH-injected newts had elevated levels of corticosterone, but suppressed time in unken. Overall, this study provides evidence that corticosterone is involved albeit not directly in mediating anti-predator behavior in newts.
