Meeting Abstract
Overwhelming evidence suggests that both acute and chronic stress physiology can be predictive of condition, thermoregulation, and survivorship, and are therefore measures of interest to ecologists. Over the past 30 years, however, the role of the sympathetic nervous system (SNS) in mediating stress-induced physiological changes has been alarmingly neglected for favor of glucocorticoid driven processes. For this reason, we investigated the influence of time-averaged SNS activity on stress-induced, thermal profiles, using captive, wild-caught Black-capped Chickadees (Poecile atricapillus; n = 20). Recent research has suggested that the temperature of peripheral tissues (specifically, tissues surrounding the eye) is responsive to acute stress in birds. Here, we tested whether such stress-induced, peripheral hypothermia is maintained under chronic stress exposure, using a paired experimental design whereby each individual was exposed to a thirty day period of randomly assigned, daily stressors (nstressors = 6, time per exposure = 20 min), and a control period of equivalent duration. Thermal profiles were monitored daily using remote infra-red thermography and compared between treatment types. Secondly, we investigated whether peripheral thermal profiles were best explained by time-averaged SNS or glucocorticoid profiles, by quantifying deposition of metanephrine, normetanephrine, and corticosterone in feathers grown throughout experimentation, and testing correlations with mean eye temperature across individuals. Our results support persistent, peripheral hypothermia under chronic stress exposure (p = 0.024, t = -2.19, nmeasurements = 7967), when ambient temperature is accounted for. Correlations between temperature of peripheral tissues and time-averaged endocrine profiles will be discussed.
