The constraints of digestive rate: An alternative model of diet selection

@article{Verlinden2005TheCO,
  title={The constraints of digestive rate: An alternative model of diet selection},
  author={C. Verlinden and Richard H. Wiley},
  journal={Evolutionary Ecology},
  year={2005},
  volume={3},
  pages={264-272}
}
SummaryA general model is developed to predict diet selection when digestive capacity is limited and when food items differ in digestibility and digestive turnover time. Under these conditions, in order to maximize the rate of energy acquisition, animals should maximize digestive rate, by selecting food with high digestibility and rapid passage through the digestive tract. They should spend as much time as they have available to search for this food. These and other predictions differ from… 

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References

SHOWING 1-10 OF 43 REFERENCES

An Analysis of Diet Selection by Large Generalist Herbivores

  • M. Westoby
  • Environmental Science
    The American Naturalist
  • 1974
A property of this "optimization model" is that the contribution of a food to the diet will sometimes vary with the food's content of a particular nutrient and sometimes will not, which might explain why no consistent relations of this kind have been found experimentally.

The allometry of food intake in grazing ruminants

(1) A simulation model of grazing mechanics in ruminants shows that, due to the allometric relations of bite size and metabolic requirements to body size, small animals are able to subsist on shorter

Diet optimization in a generalist herbivore: the moose.

  • G. Belovsky
  • Environmental Science
    Theoretical population biology
  • 1978

Herbivore Optimal Foraging: A Comparative Test of Three Models

  • G. Belovsky
  • Environmental Science
    The American Naturalist
  • 1984
The results presented here contradict Owen-Smith and Novellie's (1982) claim that linear programming is a special case and the contingency model is a representation of herbivore diet choice and the model of food energy content weighted by abundance might not be expected to work a priori, because it is not an optimal foraging model.

The Role of Foraging Time Constraints and Variable Prey Encounter in Optimal Diet Choice

  • J. Lucas
  • Environmental Science
    The American Naturalist
  • 1983
Optimal diet choice is analyzed by relaxing two sets of assumptions made in previous optimality models and it is shown that as variance in prey encounter rate increases, the time over which the forager estimates prey encounter rates will have a strong effect on the ability of the foragers to maximize the net rate of energy intake.

A Nutritional Explanation for Body-Size Patterns of Ruminant and Nonruminant Herbivores

Calculations suggest that sufficient intake of a high-fiber diet cannot be maintained to provide the energy necessary to support larger body sizes, and changing body size is postulated as a mechanism for differentiating the feeding requirements of herbivores.

On the Theory of Optimal Diets

  • H. Pulliam
  • Environmental Science
    The American Naturalist
  • 1974
Using techniques of stochastic theory, a new aproach to predicting optimal diets is developed for a mobile predator feeding on stationary prey, predicting that an animal feeding according to the dictates of the optimal diet should show no partial preferences.

Time Constraints and Diet Choice: Different Predictions from Different Constraints

  • J. Lucas
  • Biology
    The American Naturalist
  • 1985
It is shown here that the time allocated to foraging behavior may, in turn, significantly alter predictions concerning diet choice, and predictions from two classes of models that specifically address the influence of time constraints on prey selection are reviewed.

Are rumen samples representative of the diet

A model of input-content relationships was formulated to examine the effect of turnover time of botanical constituents on their relative abundance in the rumen. For a stable and diverse botanical

Optimal Foraging: A Selective Review of Theory and Tests

The general conclusion is that the simple models so far formulated are supported are supported reasonably well by available data and that the author is optimistic about the value both now and in the future of optimal foraging theory.