Patch Dynamics of a Phytophagous Mite Population Effect of Number of Subpopulations

Abstract

I conducted a field test of the hypothesis that the dynamics of a predator-prey interaction should be affected by the number of interacting subpopulations within an assemblage. I used a "successful" biological control system, the phytophagous European red mite (Panonychus ulmi) and its predator, the phytoseiid mite Typhlodromus pyri. An orchard was established where apple trees were arranged in groups of 1, 4, or 16 and the dynamics of the mite populations on the trees followed over a season. The pests reached highest densities and were most persistent on trees in the largest groups. These results are explained in terms of an interaction between prey immigration/emigration and predation.