Can Phytoseiulus persimilis (Acari: Phytoseiidae) invade rainforest fragments when its preferred prey Tetranychus urticae is present?

摘要

The Chilean predatory mite Phytoseiulus persimilis Athias-Henriot is a well known introduced biocontrol agent that has become naturalised in agricultural fields in many areas of Australia. In a previous study, subtropical rainforest remnants of Queensland were shown to be resistant to invasion by P. persimilis. To determine if this resulted from environmental preferences of P. persimilis for open, sunny habitats, we performed two tests. In the first, we introduced the predators onto potted bean plants infested with their preferred prey (Teiranychus urticae C. L. Koch) 200 m into the rainforest and in fields at two sites (Redlands and Mt Glorious) and followed population densities of both prey and predator for two weeks. We found no difference in the mean numbers of predatore between fields and rainforest. In a second expenment in a glasshouse, where the predator was given a choice between shaded and unshaded bean plants, predators preferred shaded plants. Thus, when its prey are present, P. persimilis appears to be able to exploit the rainforest habitat.