Meeting Abstract
Amphibian populations are declining worldwide, and increased exposure to environmental stressors, including diseases like Batrachochytrium dendrobatidis, has been proposed as one reason for these declines. Our goal was to use a novel, noninvasive dermal swabbing method to measure glucocorticoids and investigate the relationship among disease, environmental conditions and stress physiology in the critically endangered Wyoming toad. Our objectives were to validate the use of dermal swabs to measure cortisol using an adrenocorticotropic hormone (ACTH) challenge on 8 captive Wyoming toads (4 ACTH: 2M, 2F and 4 saline as a control: 2M, 2F); 2) compare fecal glucocorticoid metabolites (FGMs) pre- and post-ACTH experiment; and 3) investigate stress physiology of toads across three different reintroduction sites with varying population success and disease prevalence. Results validated the use of dermal swabs cortisol peaking immediately after the ACTH injection, while saline remained consistent over time (up to 2 hours). FGMs were elevated on Day 1 post-ACTH for the male and Days 2-4 for the female compared to FGMs before the experiment. Saline-injected toads had no change in FGM over time. Dermal cortisol was similar across one reintroduction site compared to captive toads. We also collected additional samples to compare habitat type and disease prevalence across two other sites. Dermal hormonal analysis is a novel tool that can be used to study amphibian stress physiology and can provide information on how environmental conditions are impacting population success.
