Interactions in a tritrophic acarine predator-prey metapopulation system: prey location and distance moved by Phytoseiulus persimilis (Acari : Phytoseiidae)

The between-plant movement of the predatory mite Phytoseiulus persimilis wa s studied in a greenhouse. The aims were to determine the distance moved by P. persimilis and the response of the predator to the location of a plant infested with two-spotted spider mite, Tetranychus urticae. In addition, we tested whether the predator exhibits random movement between plants or whe ther its dispersal is oriented. We found that a high proportion of the pred ators released on a central plant were able to reach plants at the peripher y provided the plants were connected to the central plant with 'bridges'. T he results further showed that P. persimilis does not disperse randomly to the surrounding plants. The distribution of immigrants was influenced by th e position of an infested plant in the neighbourhood, but light/shadow effe cts in the greenhouse may also influence the choice of direction. The likel y implications of the findings for biological control are discussed. Exp Ap pl Acarol 23: 21-40 (C) 1999 Kluwer Academic Publishers.