Meeting Abstract
132.1 Monday, Jan. 7 Food supplementation of Florida Scrub-Jay (Aphelocoma coerulescens) nestlings: long-term effects on hypothalamic-pituitary-adrenal axis responsiveness SMALL, TW*; BRIDGE, ES; SCHOECH, SJ; University of Memphis; University of Oklahoma; University of Memphis twsmall@memphis.edu
In a wide variety of animals, plasma glucocorticoid levels rapidly increase in response to a stressor. In Florida Scrub-Jays (Aphelocoma coerulescens), the magnitude and time course of increased corticosterone (CORT) during a restraint stress can vary greatly between individuals. These differences can be detected within a few months post-fledging, and are repeatable throughout the life of the animal, suggesting that these differences are a persistent aspect of the individual’s phenotype. Further, the differences in stress responses are correlated with life history and behavioral traits, such as an individual’s life span and degree of neophobia. The CORT phenotypes of offspring are correlated with parental CORT phenotype, but it is currently unknown if this similarity is due to genetic inheritance or other factors, such as differences in parental care, early life nutrition, or other environmental conditions. To investigate which factors are important in the development of the CORT stress response, we used a novel “SmartFeeder” design that utilizes radio-frequency identification (RFID) technology to food supplement specific individuals within a population of free-living Florida Scrub-Jays. With these feeders we delivered live mealworms to specific adult jays caring for nestlings, and thereby supplement their nestlings. Behavioral observations at supplemented and control nests confirm adults feed mealworms to nestlings. Supplemented nestlings were not larger than control nestlings and nestling baseline CORT did not differ between treatments; however, supplemented nestlings had lower stress-induced CORT levels at approximately 50 days post-fledging. Continuing research will determine if these differences persist into adulthood and if they are correlated with behavioral differences and individual success.
