A Lifetime Perspective on Foraging and Mortality

Authors: YEARSLEY J.¹; HASTINGS I.M.²; GORDON I.J.¹; KYRIAZAKIS I.³; ILLIUS A.W.²

Source: Journal of Theoretical Biology, Volume 215, Number 4, April 2002 , pp. 385-397(13)

Buy & download fulltext article:

Price: $52.63 plus tax (Refund Policy)

Abstract:

Food intake carries many potential risks which may impair an animal's reproductive success not only in the current breeding cycle, but also for the rest of its lifetime. We examine the lifetime trade-off between the costs and benefits of food intake by presenting a simple animal foraging model, where each unit of food eaten carries with it a risk of mortality. We show that the optimal food intake rate over an animal's lifetime, for both semelparous and iteroparous animals, is not maximal. Instead, animals are required to strike a balance between the immediate reproductive benefits of gathering food and the future reproductive costs incurred by the food's mortality risk. This balance depends upon the lifespan of the animal as well as the nature of the risk. Different mortality risks are compared and it is shown that a mortality risk per unit time spent foraging is not, in general, equivalent to a mortality risk per unit of food consumed. The results suggest that a mortality risk per unit of food consumed, such as that presented by the presence of a toxin or of a parasite in the diet, has important consequences for feeding behaviour and is a possible factor involved in food intake regulation. Copyright 2002 Elsevier Science Ltd. All rights reserved.

Language: English

Document Type: Research article

Affiliations: 1: Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, AB15 8QH, U.K. 2: University of Edinburgh, West Mains Road, Edinburgh, EH9 3JT, U.K. 3: Animal Biology Division, Scottish Agricultural College, West Mains Road, Edinburgh, EH9 3JG, U.K.

Publication date: 2002-04-01