System behaviour in predator‐prey interaction, with special reference to acarine predator‐prey system

Summary Laboratory experiments on the interaction between phytophagous tetranychid mites and predacious phytoseiid mites in multi‐patch systems showed that it was difficult to obtain a continued interaction between them when prey heavily over‐exploit their host plants. The experiments suggested that the stability conditions concluded from the Maynard Smith model which assumed a stable relationship between prey and resource would be of secondary importance, if the interactive behaviour between prey and resource was unstable. An acarine predator‐prey system was theoretically analyzed by simulations on the basis of the structure of the Maynard Smith model, but by introducing modifications to the model, considering several properties characteristic to the prey and predacious mites. The simulations showed that if there was resource over‐exploitation by prey, a variety of patterns could be generated in the dynamic behaviour between prey and resource, and depending on the interactive pattern, the predator‐prey system displayed a stable behaviour in some cases but in others it became unstable. To achieve a stable interaction, it was important to lower the rate of local prey extinction and this could be achieved either by predation which prevented the prey from over‐exploiting the resource or by lowering the rate of successful migration of the prey.