Diffusion models for the dispersal of insects near an attractive center

From a general point of view we discuss various models for the dispersal of insects that are attracted towards a point by some mechanism. The basic model is a diffusion with drift towards the attractive center. It is shown that most quantities of interest in the model can be found explicitly when the drift is inversely proportional to the distance from the center. Experiments to test the models are proposed, and the results of one such experiment are summarized.