Foraging

Abstract

Foraging theory can be used to explain two important phenomena, how and why organisms choose particular foodstuffs (Optimal Diet Theory) and how long individuals will remain in resource patches before seeking others (marginal value theorem). The theories are analytical and produce explicit, quantitative predictions. In order to test predictions from foraging theory, one must tweak the theory to account for details of an organism's natural history. In general, experimental tests of the theory support its predictions but most often in a qualitative, not quantitative manner. Foraging theory can be applied to a wide range of resources beyond the classic food examples including mates and hosts for parasitoids. The conditions under which a game theoretical approach is best used to explain foraging decisions are, for example when the performance of a focal individual depends on the number and behaviour of other competitors in any given patch.

Key Concepts

  • Resources (e.g. food) can vary in quality as well as in distribution (e.g. aggregated).
  • Optimal foraging theory was developed to explain how and why foods of particular quality are chosen by resource‐seeking individuals.
  • Further, because resources are often patchily distributed, foragers must decide when to give up and seek other patches. Such decisions can be understood by employing the marginal value theorem, a theorem that falls under the foraging theory umbrella.
  • Foraging theory models are quantitative and explicit. For example, they predict diet breadth (i.e. which resources should be included in the diet of a foraging individual) under a specific set of environmental conditions.
  • Foraging theory predictions can be tested using wild or domesticated organisms in the laboratory or in nature.
  • Tests of foraging theory predictions generally support the theory in a qualitative sense (e.g. the diet will expand as highest‐quality resources become rare) but often not quantitatively (e.g. the exact resource value at which diet expansion will occur).
  • Classic foraging theory ignores the physiological state of foraging organisms (e.g. energy reserves) but the theory can easily be modified to take into account such parameters.

Keywords: optimal; marginal value theorem; decisions; patch; diet; handling

Figure 1. The MVT solution for the optimal residence time (Topt) for a forager searching for food within a low‐ (blue) and high‐ (red) quality patch within the same environment.
close

References

Barrette M and Giraldeau LA (2006) Prey crypticity reduces the proportion of group members searching for food. Animal Behaviour 71: 1183–1189.

Berteaux D, Crete M, Huot J, Maltais J and Ouellet J‐P (1998) Food choice by white‐tailed deer in relation to protein and energy content of the diet: a field experiment. Oecologia 115: 84–92.

Charnov EL (1976) Optimal foraging: the marginal value theorem. Theoretical Population Biology 9: 129–136.

Cooper WE and Anderson RA (2006) Adjusting prey handling times and methods affects profitability in the broad‐headed skink (Eumeces laticeps). Herpetologica 62: 356–365.

Guillemett M and Himmelman JH (1996) Distribution of wintering common eiders over mussel beds: does the ideal free distribution apply? Oikos 76: 435–442.

Hahn S, Peter H‐U and Bauer S (2005) Skuas at penguin carcass: patch use and state‐dependent leaving decisions in a top‐predator. Proceedings of the Royal Society B 272: 1449–1454.

Illius AW, Gordon IJ, Elston DA and Milne JD (1999) Diet selection in goats: a test of intake‐rate maximization. Ecology 80: 1008–1018.

Jiang Z and Hudson RJ (1993) Optimal grazing of wapiti (Cervus elaphus) on grassland: patch and feeding station departure rules. Evolutionary Ecology 7: 488–498.

Kotler BP, Brown JS and Bouskila A (2004) Apprehension and time allocation in gerbils: the effects of predatory risk and energetic state. Ecology 85: 917–922.

Noonburg EG, Newman LA, Lewis M, Crabtree RL and Potapov AB (2007) Sequential decision‐making in a variable environment: modeling elk movement in Yellowstone National Park as a dynamic game. Theoretical Population Biology 71: 182–195.

Persons MH and Uetz GW (1997) The effect of prey movement on attack behavior and patch residence decision rules of wolf spiders (Araneae: Lycosidae). Journal of Insect Behavior 10: 737–752.

Peterson JH and Roitberg BD (2016) Variable flight distance to resources results in changing sex allocation decisions, Megachile rotundata. Behavioral Ecology and Sociobiology 70: 247–253.

Pulliam HR (1974) On the theory of optimal diets. American Naturalist 108: 59–74.

Roitberg BD (1990) Optimistic and pessimistic fruit flies: evaluating fitness consequences of estimation errors. Behaviour 114: 65–82.

Schoener TW (1971) The theory of feeding strategies. Annual Review of Ecology and Systematics 2: 369–404.

Ward D (1991) The size selection of clams by African black oystercatchers and kelp gulls. Ecology 72: 513–522.

Further Reading

Clark CW and Mangel M (2000) Dynamic State Variable Models in Ecology. New York: Oxford University Press.

Giraldeau L‐A and Caraco T (2000) Social Foraging Theory. Princeton, NJ: Princeton University Press.

Krebs JR and Davies NB (eds) (1978) Behavioural Ecology: An Evolutionary Approach. Sunderland, MA: Sinauer Press.

Lima SL and Dill LM (1990) Behavioral decisions made under the risk of predation: a review and prospectus. Canadian Journal of Zoology 68: 619–640.

Nonacs P (2001) State dependent behavior and the marginal value theorem. Behavioral Ecology 12: 71–83.

Stephens DW and Krebs JR (1987) Foraging Theory. Princeton, NJ: Princeton University Press.

Stephens DW, Brown JS and Ydenberg R (eds) (2007) Foraging: Behavior and Ecology. Chicago, IL: University of Chicago Press.

Wajnberg E (2006) Time allocation strategies in insect parasitoids: from ultimate predictions to proximate behavioral mechanisms. Behavioral Ecology and Sociobiology 60: 589–611.

Wajnberg E, Bernstein C and van Alphen J (eds) (2008) Behavioral Ecology of Insect Parasitoids: From Theoretical Approaches to Field Applications. Oxford: Blackwell Press.

Wajnberg E, Roitberg BD and Boivin G (2016) Using optimality models to improve the efficacy of parasitoids in biological control programmes. Entomologia Experimentalis et Applicata 158: 2–16.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Roitberg, Bernard D, and Roitberg, Gabi(Sep 2016) Foraging. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0003228.pub2]