Effect of initial asymmetry in Magellanic penguin chick's performance. A
cross-fostering experiment.
- Nahuel Marchisio,
- Melina Barrionuevo,
- Esteban Frere
Melina Barrionuevo
Universidad Nacional de la Patagonia Austral
Author ProfileEsteban Frere
Universidad Nacional de la Patagonia Austral
Author ProfileAbstract
When chicks in a brood hatch asynchronously, the first to hatch gets fed
sooner, creating a hierarchy of asymmetries in the brood. In species
that suffer from brood reduction, this asymmetry can facilitate the
death of one chick during periods of low food availability. The aim of
this study was to analyze the effect of initial asymmetries on the
growth and survival of Magellanic penguin Spheniscus magellanicus
chicks, after disentangling the effects of parental condition, during
four breeding seasons. We manipulated chicks' asymmetries within the
brood by performing a cross-fostering experiment, creating broods with
different weight ratios in a colony located in Isla Quiroga, Santa Cruz,
Argentina. We found that weight ratio determines the asymmetry within
the brood throughout the entire breeding season, and that final
asymmetry also depends on the study season. Chicks that hatch last have
a greater chance of survival when the weight ratio with their older
sibling is closer to 1. Parental body condition affects chick growth but
not asymmetry. To conclude, parents do not reverse the effect of initial
asymmetry in post-hatching stages, even during breeding seasons of high
reproductive success.