Optimal Foraging

by

David W. Stephens

• LAST REVIEWED: 23 May 2012
• LAST MODIFIED: 23 May 2012
• DOI: 10.1093/obo/9780199830060-0057

Introduction

All organisms face problems of resource acquisition, and in the broadest sense foraging theory is an attempt to make generalizations about the processes associated with resource acquisition. In theory, resource acquisition is a very general problem, but in practice foraging theory is closely linked to the study of animals and their behavior, since feeding—acquiring the tissue of living things to consume—is, after all, a defining property of animals. Optimal foraging models take an adaptationist perspective in the sense that they ask which strategy among a given “feasible” set will lead to the highest evolutionary fitness, and in making these calculations, students of foraging often use the mathematical tools of optimization. The first optimal foraging models appeared in the late 1960s and 1970s. Most of those that we now see as the “classic foraging models” date to this time. The subfield of foraging has a split personality. The early pioneers in the field (Charnov, Orians, MacArthur, Pianka, Parker) clearly saw themselves as ecologists, and they were motivated by the idea that an understanding of predator behavior would lead to a broader understanding of ecological phenomena such as the distribution and abundance of both prey and predators. Yet, modern foraging theory is more closely allied to behavioral ecology, which seeks to predict behavior in ecological contexts. Foraging theory has influenced disciplines far afield from ecology or even biology, including anthropology, economics, computer science, robotics, neuroscience, psychology, cognitive science, and marketing.

General Overviews

The reader can get a fairly concise overview of the field via two books. The widely cited Stephens and Krebs 1986, simply entitled Foraging Theory, presents the classical models in a coherent and fairly readable way and has very wide appeal to both biological and nonbiological audiences. A newer volume, Stephens, et al. 2007, follows the threads that began in the 1986 book. Although it is reasonable to say that both books provide overviews, they are complementary. Most readers feel that they need some familiarity with the older book to understand the themes developed in the newer one. Kamil, et al. 1987 offers a slightly more empirical and less cohesive approach to foraging, at about the same time as Stephens and Krebs. Pyke, et al. 1977 provides an overview that was very influential in its day, and Hughes 1993 offers an interesting overview of problems in diet choice. Finally, the privately published Charnov and Orians 1973 (probably first circulated in 1973) provides a historically important record of the beginnings of the topic. In its day, it was passed from one hand to another as loose sheets of increasingly poor photostatic copies.

• Charnov, Eric L., and G. H. Orians. 1973. Optimal Foraging: Some Theoretical Explorations.

  A historically important unpublished manuscript that the authors distributed privately. It presents a very readable development of the two basic rate-maximizing models. A must-have for anyone interested in the history of the field, even if it is challenging to find.Available online by subscription.

• Hughes, Roger N., ed. 1993. Diet selection: An interdisciplinary approach to foraging behaviour. New York: Wiley-Blackwell.

  A relatively early compilation of papers about foraging that took a broader perspective than “optimal foraging.” It departs from the conventions of its day by including things such as psychological and digestive constraints. It was prescient in the sense that these issues are now a key part of the broader topic of foraging theory.

• Kamil, Alan C., John R. Krebs, and H. Ronald Pulliam, eds. 1987. Foraging behavior. New York: Plenum.

  DOI: 10.1007/978-1-4613-1839-2

  This volume is the second in a series that summarized both empirical and theoretical work in foraging. Many of the themes in modern foraging theory such as cognition, and predator tradeoffs, were first developed here.

• Pyke, Graham H., H. Ronald Pulliam, and E. L. Charnov. 1977. Optimal foraging: A selective review of theory and tests. Quarterly Review of Biology 52:137–154.

  DOI: 10.1086/409852

  Probably the earliest single exposition of foraging theory. Still quite readable, this paper played a key role in establishing the field as a coherent entity within ecology and behavior.

• Stephens, David W., Joel S. Brown, and Ronald C. Ydenberg. 2007. Foraging: Behavior and ecology. Chicago: Univ. of Chicago Press.

  The most up-to-date single source in the field. It covers standard models, neuroscience, cognition, food storage, digestion, predator avoidance, and ecology.

• Stephens, David W., and John R. Krebs. 1986. Foraging theory. Princeton, NJ: Princeton Univ. Press.

  Almost certainly the most widely cited work in the field. An analysis by Sam Elworthy (Bulletin of the British Ecological Society 38 [2007]) lists it as the ninth most cited nontextbook volume in evolution and ecology. Its chief value is that it offers a clear and accessible narrative explaining the now classic approach to foraging.