Incubation increases oxidative imbalance compared to chick rearing in a seabird, the Magellanic penguin (Spheniscus magellanicus)

COLOMINAS-CIURÓ R.; BERTELLOTTI M.; CARABAJAL E.; D'AMICO V.L.; BARBOSA A.

MARINE BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2017 vol. 164

0025-3162

Magellanic penguins (Spheniscus magellanicus) breed colonially and their breeding cycle comprised different periods (courtship and nest building, incubation, guard phase and crèche) which have different energy requirements. Energy use has been related with oxidative balance. It is then expected that activities which requires a high use of energy could generate higher oxidative stress. Chick rearing during guard phase involves a high parental investment (e.g. chick feeding and greater nest protection) than during incubation. Therefore, we expected oxidative stress to be higher in the former. Fieldwork was conducted in a Magellanic penguin colony located in Estancia San Lorenzo (42⁰ 05?S, 63⁰ 49?W), Peninsula Valdes, Argentina, during the breeding season of 2014-2015. All penguins sampled were nesting under shrubs incubating two eggs or rearing two chicks (to avoid uneven parental effort). Surprisingly, our results did not support our initial prediction. Incubating adults seems to unbalance their oxidative status showing significantly lower antioxidant levels. However, oxidative damage did not show a significant variation between the two breeding periods studied. Further, we did not find differences in oxidative status between sexes. Our results seem to suggest that incubation could be a highly demanding activity compared to chick rearing in terms of oxidative balance. Differential foraging effort could explain such results as Magellanic penguins adjust their foraging location to prey availability performing longer foraging trips during incubation than during chick rearing which increases the energy costs and therefore imbalance penguins oxidative status.