Meeting Abstract
Disease exposure is a universal threat to all organisms, and self-defense can occur in a variety of ways. Individuals can proactively prevent disease through avoidance behaviors. However, if they become infected, individuals can activate the immune response to control the infection. It is hypothesized that a trade-off occurs between avoidance behaviors and immune response activation because of costs associated with each strategy. Individuals may balance behavioral and immunological strategies to provide optimal protection against disease, but the physiological mechanism underlying this proposed trade-off is unknown. We conducted hormone-dosing experiments with the glucocorticoid corticosterone (CORT) to address this gap. CORT is produced as a result of activation of the hypothalamic-pituitary-adrenal (HPA) axis and induces a variety of physical and behavioral changes. Acute exposure to stressors that cause a short-term increase in CORT may boost the immune response of an individual and cause them to associate more with sick conspecifics. With a captive population of zebra finches (Taeniopygia guttata), we orally dosed focal birds with exogenous CORT immediately prior to hour-long association trials. We then inoculated birds with lipopolysaccharide (LPS) and collected blood samples to measure baseline and post-LPS acute phase protein (haptoglobin) levels. We predict that CORT-treated birds will spend more time with sick individuals and have higher average haptoglobin levels than birds from the control group. Studying the role of stress hormones in strategy utilization will bring insight into the persistence of variation in susceptibility to diseases.
