Meeting Abstract
Acute, short-term effects of early-life stress and associated glucocorticoid upregulation on behavior are widely documented across vertebrates. However, the persistence and severity of these effects are largely unknown for wild species through adulthood. Here, we investigate long-term effects of experimental post-natal increases in a circulating glucocorticoid on antipredator behavior and a hormonal indicator of reproductive readiness in house sparrows (Passer domesticus). We manipulate circulating corticosterone concentration in wild, free-living nestlings, transfer fledglings to captivity, and test juveniles and adults for two measures of antipredator behavior: evasiveness during a direct human encounter, and propensity to escape from a risky environment. We also administer a gonadotropin-releasing hormone challenge to adult females and measure luteinizing hormone response as an indicator of breeding readiness. We find no effect of early-life stress hormone manipulation on escape behavior, but a delayed effect on evasive behavior: evasive behavior was compromised in adults but not juveniles, and influenced by current body condition. Early-life glucocorticoid manipulation also interacted with mass to influence breeding readiness: treated females that were heavy had a stronger luteinizing hormone response than control females. These results highlight the importance of state-behavior interactions and life stage in assessing long-term effects of early-life stress, and provide rare evidence for delayed effects of early-life stress to adults of a wild avian species.
