Meeting Abstract
Early-life stress has long-term effects on animal physiology, however, the magnitude and direction (i.e. positive or negative) of these effects is inconsistent across studies, probably due to variation in duration of stressors, type of stressors, and life stage at which effects are evaluated. In the wild, transient early-life stressors are likely as common as chronic stressors, yet have received less attention. Here, we investigate long-term effects of early-life transient surges in stress hormones in wild house sparrows (Passer domesticus). We non-invasively increased circulating corticosterone in free-living nestlings at eight, nine, and eleven days post-hatching. At fledging, all nestlings (70 nestlings from 23 nests) were taken into captivity. Body size, body condition, hematocrit, PHA-induced skin swelling, capture-restraint stress response, and mortality were analyzed at the nestling, juvenile, and adult stages. Compared to corticosterone-fed nestlings, control nestlings appear to have been given a “silver spoon”. Early-life stress decreased bird size, body condition, and had long-term effects on stress-induced corticosterone. However, the magnitude of the morphological effects weakened across life stage due to phenotypic plasticity (not selective mortality). There was no effect of treatment on mortality until the adult stage, when treated birds had a higher probability of mortality than controls. Our results reveal that some, but not all, long-term effects of early-life stress may be mitigated by phenotypic plasticity.
