Marginal value theorem

Marginal value theorem
The optimal time spent in a patch is given by the tangent to the resource intake curve that departs from the expected transit time value. Any other line crossing the resource intake curve has a shallower slope and thus a sub-optimal resource intake rate.

In behavioral ecology, the marginal value theorem (MVT) considers an optimally foraging animal exploiting resources distributed in patches and that must decide when to leave a patch to start searching for a fresh one. The animal is assumed to have evolved to optimize a cost/benefit ratio: searching for and manipulating food is costly, while consuming food is a benefit. The decision taken by animals appears to be based on an expected transit time among patches and an observed intake rate within each patch. Examples include bees visiting flowers, birds eating berries, or even mobile phone shop owners (in which case the "resource" being exploited is paying customers).

The theorem predicts that individuals will stay longer:

  • as the distance between patches increases,
  • when the environment as a whole is less profitable.

The theorem states that the optimal time spent in a patch is given by the tangent to the resource intake curve that departs from the expected transit time value.

Plants have also been shown to obey the predictions of the MVT. Plant roots traveling through soil will slow their growth rate in order to remain in patches of higher soil resources for longer periods of time in exactly the same way as animals.

The MVT has been criticised on the grounds that few foragers are optimal (typical limiting factors include inability to assess exploitation rate and lack of knowledge of distant patch existence). Nevertheless, it predicts behavior that is compatible with many types of real forager behavior.

Example

A common illustration is elicited with apple picking in humans. When one first arrives at a new apple tree, the number of apples picked per minute is high but it rapidly decreases. Strategies where too few apples are picked from each tree or where each tree is exhausted are sub-optimal because they result, respectively, in time lost travelling among trees or picking the hard to find last few apples from a tree. The optimal time spent picking apples in each tree is thus a compromise between those two strategies, which is quantitatively described by the MVT.

See also

References

  • Charnov, E. L. 1976. Optimal foraging: the marginal value theorem. Theoretical Population Biology 9:129–136.
  • Charnov, E. L. 1976. Optimal foraging: attack strategy of a mantid. The American Naturalist 110:141–151.
  • McNickle, G.G., and Cahill, J.F. Jr. 2009. Plant root growth and the marginal value theorem. Proceedings of the National Academy of Sciences USA. 106(12): 4747–4751.

Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • Bayes' theorem — In probability theory, Bayes theorem (often called Bayes law after Thomas Bayes) relates the conditional and marginal probabilities of two random events. It is often used to compute posterior probabilities given observations. For example, a… …   Wikipedia

  • Cost-of-production theory of value — In economics, the cost of production theory of value is the theory that the price of an object or condition is determined by the sum of the cost of the resources that went into making it. The cost can compose any of the factors of production… …   Wikipedia

  • utility and value — ▪ economics Introduction       in economics, the determination of the prices of goods and services.       The modern industrial economy is characterized by a high degree of interdependence of its parts. The supplier of components or raw materials …   Universalium

  • Coase theorem — In law and economics, the Coase theorem (pronounced /ˈkoʊs/), attributed to Ronald Coase, describes the economic efficiency of an economic allocation or outcome in the presence of externalities. The theorem states that if trade in an externality… …   Wikipedia

  • Expected value — This article is about the term used in probability theory and statistics. For other uses, see Expected value (disambiguation). In probability theory, the expected value (or expectation, or mathematical expectation, or mean, or the first moment)… …   Wikipedia

  • List of mathematics articles (M) — NOTOC M M estimator M group M matrix M separation M set M. C. Escher s legacy M. Riesz extension theorem M/M/1 model Maass wave form Mac Lane s planarity criterion Macaulay brackets Macbeath surface MacCormack method Macdonald polynomial Machin… …   Wikipedia

  • Maximum sustainable yield — In population ecology and economics, maximum sustainable yield or MSY is, theoretically, the largest yield (or catch) that can be taken from a species stock over an indefinite period. Fundamental to the notion of sustainable harvest, the concept… …   Wikipedia

  • Diminishing returns — Economics …   Wikipedia

  • Stratégie optimale de recherche de la nourriture — C’est en 1966 qu’Emlen, Mac Arthur et Pianka établissent pour la première fois la théorie de la stratégie optimale de recherche de nourriture ou optimal foraging qui consiste à rechercher la proie optimale avec le moins de contraintes possibles… …   Wikipédia en Français

  • MVT — may refer to any of the following: * Multivariate testing, a technique for testing hypotheses on complex multi variable systems, especially used in testing market perceptions. * mean value theorem, Calculus theorem * marginal value theorem, a… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”