Determinants of within- and among-clutch variation in yolk corticosterone in the European starling.

摘要: Maternal glucocorticoids are known to affect offspring phenotype in numerous vertebrate taxa. In birds, the maternal transfer of corticosterone eggs was recently proposed as a hormonal mechanism by which is matched relative quality environment. However, current hypotheses lack supporting information on both intra- and inter-clutch variation yolk for wild birds. As such, we examined levels population European starlings (Sturnus vulgaris). condition, clutch size nesting density were all negatively related deposition; females with high condition indices, those laying larger clutches high-density associations deposited lower amounts hormone into than low small isolation. Alternatively, found no effects age or human disturbance deposition. Intra-clutch significant, increasing across sequence sizes examined, difference between first last-laid being greater large versus clutches. Given reported growth, intra-clutch has potential alter competitive environment within brood. Furthermore, our results indicate that can originate from mother's well her breeding The presence inter-female particular an important pre-requisite testing whether exposure maternally-derived mechanistic link phenotypic plasticity quality.