Document: SHA-3-92-5

Adaptive feeding across environmental gradients.

RICHARDS, S.A.* ¹ and W.G.WILSON ²

University of Amsterdam, NL ¹
Duke University, NC USA ²

Abstract:
A mathematical model is used to investigate a consumer's adaptive feeding response to environmental gradients. Consumers compete exploitatively for a renewing resource that is distributed among many discrete patches. Each consumer removes resources from a patch down to some threshold density before seeking resources elsewhere. Assuming consumers trade off resource extraction with patch access and predation we show that for a given environment there often exists a single evolutionarily stabe feeding threshold and it is an evolutionary attractor. The model predicts that when the environment becomes less harsh (i.e., the risk of predation is reduced, or patches become more abundant) selection favors consumers with a lower feeding threshold. The model also predicts that a population that adapts its feeding threshold in a varying environment can exhibit quite different dynamics when compared with a population that exhibits a fixed feeding threshold. We compare and contrast our results with the well known marginal value theorem.

Keywords: adaptive dynamics, foraging theory

This abstract is being presented at: 9:15 AM in session:
Oral Session #39: Theoretical Ecology.