Population dynamics of Orius laevigatus and Frankliniella occidentalis: a mathematical modelling approach

A mathematical model was utilised to study the population dynamics of the predator Orius laevigatus and its prey, Frankliniella occidentalis. The INSIM programme, a simulation environment for chained boxcar trains and age-structured populations, was used for the simulations. The population interactions between O. laevigatus and F. occidentalis were simulated with differents ratios of prey and predators. The simulations demonstrated that releasing Orius predators 10 day after the appearance of thrips, they can effectively control pest populations. The predator showed to be particularly effective when released in a 1:1 prey: predator ratio. Although the simulations are preliminary, they underline the importance of timing releases of Orius and of certain prey:predator ratios. In the Orius/thrips system, other variables like the influence of the host plant, like architecture and chemistry, and the (micro-)climate were not considered. For this, a model needs to be developed which is able to simulate a more complex and realistic system. However, our first simulations show that Orius can be an effective in controlling thrips population, confirming field data collected in northern Italy.