This provided a mechanism of selection that dramatically increased target size, allowing for a powerful selective force that would produce larger eggs. Assuming the resources available to produce pheromone were proportional to egg volume, the target area was determined as the radius of diffusion of the pheromone's active space, proportional to the rate of pheromone production, and this radius squared would be the target size. The results determined by Dusenbery suggested that this selection process would still occur if the assumption was lessened to only include pheromone production as proportional to egg surface area.