SIMULATION AND EQUATION MODELS OF INSECT POPULATION-CONTROL BY PHEROMONE-BAITED TRAPS

A spatial-temporal model for personal computers is developed that simu lates trapping of an insect population based on trap and population pa rameters that can be varied independently. The model allows individual ''insects'' to move forward at any step size with fight or left turns within any specified angle taken at random. The x and y axes of the a rea within which insects move can be varied as well as the number of i nsects, their flight speed, and the duration of the control period. In addition, the number of pheromone-baited traps, their placement in a grid or at random (with a variable degree of spacing), and their effec tive catch radius (proportional to pheromone release rate) can also be varied. Simulations showed that catch was similar regardless of wheth er traps were placed in a grid or practically at random (random placem ent but no traps were allowed to overlap in their effective catch radi i). Iterative equations were developed for computer that can rapidly o btain values that correspond to the mean results from the slower simul ation model. Based on a set of input parameters, the equations determi ne the percentage of the population that should be caught during a spe cified time, the time required to catch a specified proportion of the insects, and the number of traps necessary to catch the population pro portion in the time period. The effects of varying the number of insec ts, flight speed, trap radius, and number of traps on the percent cont rol or time to catch all insects are presented. Population control of the bark beetle Ips typographus was simulated using realistic pheromon e trap and population parameters. A discussion of insect and bark beet le (Coleoptera: Scolytidae) population control using pheromone traps i s presented.