Environmental Drivers of Growth and Oxidative Status during Early Life in a Long-Lived Antarctic Seabird, the Adélie Penguin

Abstract

In vertebrates, developmental conditions can have long-term effects on individual performance. It is increasingly recognized that oxidative stress could be one physiological mechanismconnecting early-life experience to adult phenotype. Accordingly, markers of oxidative status could be useful for assessing the developmental constraints encountered by offspring. Although some studies have demonstrated that developmental constraints are associated with high levels of oxidative stress in offspring, it remains unclear how growth, parental behavior, and brood competitionmay altogether affect oxidative stress in long-lived species in the wild. Here, we investigated this question in a long-lived Antarctic bird species by testing the impact of brood competition (e.g., brood size and hatching order) on body mass and on two markers of oxidative damage in Adélie penguin chicks.We also examined the influence of parental effort (i.e., foraging trip duration) and parental body condition on chick body mass and oxidative damage. First, we found that brood competition and parental traits had significant impacts on chick bodymass. Second, we found that chick age and, to a lesser extent, chick body mass were two strong determinants of the levels of oxidative damage inAdélie penguin chicks. Finally, and importantly, we also found that brood competition significantly increased the levels of one marker of oxidative damage and was associatedwitha lower survival probability.However, parental effort and parental condition were not significantly linked to chick levels of oxidative damage. Overall, our study demonstrates that sibling competition can generate an oxidative cost even for this long-lived Antarctic species with a limited brood size (maximum of two chicks).