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State-Dependent Energy Allocation in Variable Environments: Life History Evolution of a Rotifer
Kyle W. Shertzer and Stephen P. Ellner
Vol. 83, No. 8 (Aug., 2002), pp. 2181-2193
Published by: Wiley
Stable URL: http://www.jstor.org/stable/3072050
Page Count: 13
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We present a framework for studying the evolution of state-dependent life history strategies in unpredictable environments. A dynamic energy budget model tracks the flow of energy through individuals and is parameterized using the rotifer species Brachionus calyciflorous. Ingested energy is allocated between new growth, energy reserves, and reproductive effort, in proportions determined by the organism's physiological state, leading to a three-way trade-off when food supplies are unpredictable. The model generates testable predictions regarding how variability in food affects optimal allocation strategies. There is selection for indeterminate growth and for norms of reaction in body size, storage, and age at maturity. Harsher environments select for smaller sizes and increased storage and, consequently, greater ability to withstand starvation. The model's predictions about body size, age at maturity, and effects of food deprivation are consistent with experimental results for B. calyciflorous, indicating that these life history traits have all been shaped by evolution of energy allocation and storage strategies in response to environmental variability.
Ecology © 2002 Wiley