Modelling the population interactions between the crown weevil Mogulones larvatm and its host plant Echium plantagineum

摘要

A biological control program against Paterson's curse, Echium plantagineum, in Australian pastures has been underway since the late 1970s. The most successful biological control agent to date has been the root-crown weevil Mogulones larvatus. This paper conceptually presents a population model for the interactions between E. plantagineum and the crown weevil based on field collected ecological data. We show how this model can be used to predict the impacts of biological control of the weevil on thisweed. We also illustrate that increasing complexity in the model appears to indicate that over-simple ecological models of weed biological control systems may over-estimate long-term impacts on the target weed. Impact predictions are presented of the likely long-term reductions of Paterson's curse that we expect to see in the field, and show that these predictions are at least reasonably reliable when compared to field impacts recorded so far.