Brownian motion with repulsive polar drift: a model for insect dispersal

Abstract

A study is made of the movement of the white-fringed weevil in an open field, with systematic experimental data provided. A survey of the literature on the subject and the initial impression of the data suggest that a diffusion model would be inadequate. Therefore the diffusion model is modified to incorporate a radial drift component, and we find that this fits the data better using ad hoc statistical tests. Parameters for the movement are estimated and no evidence is found for rejecting the diffusion-drift model over periods for which the environment is stable.