Meeting Abstract
Acute challenges initiate a suite of physiological responses including activation of the sympathetic nervous system and hypothalamic-pituitary-adrenal axis. Collectively these responses promote energy mobilization and resource allocation to support survival. Here we characterized the glucocorticoid and hyperglycemic response to a standard acute handling stressor in a free-living population of Mountain White-crowned Sparrows and modeled potential predictors of the glucose and glucocorticoid response to challenge. Sparrows were trapped in seed-baited potter traps at Tioga Pass Meadow, CA during the early-mid breeding season (May-June, 2018). Blood samples were collected at 0, 15 and 30 min post-capture. Blood glucose was quantified in the field using a FreeStyle Lite meter, and glucocorticoid levels were analyzed in the lab. Consistent with previous research in this population, blood glucose and glucocorticoid levels respond positively to challenge. Glucose increased 34% above baseline by 15 min and 54% 30 minutes post capture. Glucocorticoid levels increased 309% above baseline by 15 min and 500% by 30 min post-capture. Potential predictors of glucose and glucocorticoid mobilization were modeled using scaled body mass, fat score, hematocrit, sex, date and bleed delay time as variables. The most prominent predictor of both glucocorticoid and glucose mobilization was fat score. These results suggest that stored lipid-based resources influence the physiological response to stress. Future studies should examine additional energy substrates such as triglycerides and cholesterol to further tease apart the physiological response to challenge.
