© 1995 International Society for Behavioral Ecology
research-article |
Deducing implications of fitness maximization when a trade-off exists among alternative currencies
aDepartment of Economics, University of Michigan Ann Arbor, MI 48109, USA bDivision of Biostatistics, School of Public Health, University of California Berkeley, CA 94720, USA cMorgan Stanley & Co., Inc. New York, NY 10019, USA
ABSTRACT
While the theory of natural selection posits that those behaviors maximizing reproductive success ("fitness") tend to survive, behavioral ecologists more frequently explain observed behaviors as maximizing some "currency" on which fitness depends. In the case of optimal foraging theory, for example, the currency is the long-term rate of energy intake. This currency approach is adopted because little is known about the form of the fitness function itself. A weakness of the approach is that reproductive success often depends on more than one currency and behaviors which augment one currency may reduce another. We explain how to deduce from the hypothesis of fitness maximization testable qualitative and quantitative predictions about behavior when such trade-offs exist among currencies and little is known about the fitness function. The methodology we describe is central to microeconomic theory, and its usefulness explains the central role accorded "efficiency conditions" in that theory. We expound the approach entirely in terms of two biological examples: a preliminary example involving flower replacement by a perennial and a more elaborate one involving over-winter hoarding by a female mammal.
Key words: currency, economic efficiency, fitness, foraging, hoarding, optimal control, optimization. [Behav Ecol 6: 424–434 (1995)].