An agent-based event driven foraging model

James J. Anderson

School of Aquatic and Fishery Sciences

University of Washington

Seattle WA 98195

E-mail: jim@cbr.Washington.edu

Citation: Anderson, James J. 2002. An agent-based event driven foraging model. Natural Resource Modeling 15(1): 55-82.

A game-theoretic foraging model is developed in an agent-based framework. The animal's environment is described in terms of agents representing prey,predators and the habitat. The animal has two modes of behavior for each agent: tactical mode behaviors alter the outcomes of the events and strategic mode behaviors alter the probability of future events. Possible event outcomes are represented as utilities which have both benefit and cost components. The probabilities of successful behaviors are tracked via short-term (tactical), intermediate-term (strategic) and long-term (reference) memories. Probabilities change continually through the moment-to-moment events,and switches in behavior occur when the expected utility of one behavior exceeds that of another. At the switch point,the expected utilities of the behaviors are equivalent; through this property the model parameters can be calibrated from behavioral experiments. A bluegill foraging study on giving-up time is used to calibrate the model and then habitat foraging is simulated. Problems with interpreting behavioral studies without fully characterizing the multiple scales of interactions with agents are discussed.