University of Tasmania
CRESSWELL_2007_weight_loss_macaroni.pdf (476.97 kB)

Weight loss during breeding is adaptive for female macaroni penguins, Eudyptes chrysolophus

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journal contribution
posted on 2023-05-20, 01:25 authored by Katherine CresswellKatherine Cresswell, Tarling, GA, Trathan, PN
Question: How does the female macaroni penguin balance her own needs with those of her chick during breeding? Features of the model: We model the behaviour of female macaroni penguins during a sensitive life-history stage as a function of the availability of their main prey species, Antarctic krill (Euphausia superba), using stochastic dynamic programming. In the model, females maximize accumulated delivery to the chick, accounting for metabolic losses. Chick fullness is included as a state in the model. Range of key variables: We test three scenarios for krill availability, which changes with distance from the nest. In the first, krill abundance increases with distance from the nest, with no variability in the reward at each distance. In the second, variability increases proportionally with the increasing amount of krill available at each distance from the nest. In the third, the abundance of krill at each distance from the nest is constant, but variability decreases further from the nest. Conclusions: Natural selection should produce females that sacrifice their own condition to meet the increasing demands of their chicks. We predict a weight loss of 10-20%, which is comparable to the empirical average of 14%. We also predict that females will endure the cost of travelling further from the nest to obtain a more predictable meal of krill, even if the mean reward does not change with distance from the nest.


Publication title

Evolutionary Ecology Research










Institute for Marine and Antarctic Studies


Evolutionary Ecology Ltd

Place of publication

Univ Arizona, 321 Biosciences West, Tucson, USA, Az, 85721

Rights statement

© 2007 Katherine A. Cresswell

Repository Status

  • Open

Socio-economic Objectives

Biodiversity in Antarctic and Southern Ocean environments; Expanding knowledge in the biological sciences