THE MYTH OF RANDOM MOVEMENT - OLD CONCEPTS WITH A NEW TWIST

A stochastic mode for local movement (foraging) of individual insects in the absence of directional stimuli is presented. The model describe s movement in terms of step length and turning angle, with a continuou s shift from a stochastic spiral pattern to restricted random search t o straight line 'escape.'' In comparison with purely restricted random search, this new model allows individuals to find resources more quic kly when resources are present and to leave a region when resources ar e not present. Aspects of model sensitivity are evaluated and predicti ons of the models regarding predator/prey interactions are examined.