114.4 Saturday, Jan. 7 Corticosterone Responsiveness at Nutritional Independence Predicts Behavior Nine Months Later in the Florida Scrub-Jay (Aphelocoma coerulescens). BEBUS, S.E.*; SMALL, T.W.; ELDERBROCK, E.K.; HEISS, R.S.; SCHOECH, S.J.; University of Memphis; University of Memphis; University of Memphis; University of Memphis; University of Memphis email@example.com
Early environment can shape the phenotype of an individual through modification of its genetic information. Pre- and post-natal exposure to the adrenal steroid hormone, corticosterone (CORT), has been shown to mediate environmental effects via epigenetic alteration of the hypothalamic-pituitary-adrenal (HPA) axis in a manner that results in long-term changes to the behavior and physiology of an organism. Both baseline and stress-induced CORT levels of Florida scrub-jays (Aphelocoma coerulescens) were measured at nutritional independence (~ 70 days post-hatch), some 7 – 8 months prior to behavioral tests. Then, we assessed the behavioral response of individuals presented with food (peanuts) near a novel object as a measure of personality. Two tests, each utilizing a different object, were conducted on free-living birds in their home territories at 10-11 months of age. In the ‘harder’ test, birds were required to cross a bright orange ring (60 cm diameter) to obtain peanuts. In the ‘simpler’ test, peanuts were placed at the base of a mirrored ball (8 cm diameter). A test was completed when an individual approached or crossed the novel object and took a peanut. Individuals were separated into three groups based on their responses. Group 1 completed both tests, group 2 completed the mirrored ball test but not the ring test, and group 3 did not complete either test. Corrected integrated CORT levels differed among groups, with the highest levels in group 3 and the lowest levels in group 1. The results indicate that stress responsiveness, as measured by stress-induced CORT levels, is predictive of personality along a shy-to-bold continuum in non-manipulated free-living birds.