Simulation of Professor Utida’s Classic Experiment on an Interaction Between the Azuki Bean Weevil and its Parasitic Wasp

Abstract

This paper attempts to further analyze and synthesize Professor Utida’s classic experiment with the azuki bean weevil, Callosobruchus chinensis, and the braconid wasp, Heterospilus prosopidis (Viereck). First, the density-dependent structure of the host-parasitoid interaction system is examined by the reproduction surfaces of both species. To facilitate the examination, the concept of conditional reproduction curves is introduced. A simple model is then constructed to represent the reproduction surfaces. The fluctuation in the wasp sex ratio is shown to be a major perturbation factor that causes the deviations of data points from the wasp reproduction surface. Finally, a simulation of the system dynamics is attempted, using the estimated density-dependent structure of the system and the hypothesis of perturbation by the variation in the wasp sex ratio. The dynamic pattern thus simulated closely resembles the observed pattern.