Meeting Abstract

63.3  Jan. 7  Exposing the embryo to maternal stress: an adaptive predictive mechanism or an unavoidable developmental cost? LOVE, Oliver/P*; WILLIAMS, Tony/D; Simon Fraser University, Canada; Simon Fraser University, Canada olovea@sfu.ca

How and why maternal stress affects offspring phenotype has become a subject of considerable interest in studies spanning numerous vertebrate taxa. In birds, embryonic exposure to elevated maternal stress hormones can reduce multiple measures of nestling quality, which could be interpreted as a proximate cost to the offspring and an ultimate cost to the mother. However, we recently suggested that the transfer of the maternal stress hormone corticosterone to eggs may represent an adaptive mechanistic link between maternal quality and sex-biased maternal investment in offspring. Here we present results from a recent field experiment in the European starling (Sturnus vulgaris) combining both a manipulation of yolk corticosterone (egg hormone injections) and maternal quality (feather-clipping of mothers). Low quality (feather-clipped) mothers raising corticosterone-exposed offspring fledged more young of higher quality than low quality mothers raising control young. Furthermore, low-quality females that raised corticosterone-exposed young in the first brood also appear to fledge higher quality young in their second brood attempts than low quality females originally raising control young. Finally, return rates (survival) of low-quality females that raised hormone-exposed young the previous year were higher than those of low quality females that raised control young. These preliminary results indicate that the transfer of corticosterone to eggs is adaptive in that it matches the quality of a mother to the offspring she will rear. Moreover, this adaptive mechanism increases fitness in future reproductive attempts and maximizes survival of mothers.