Figure 4.

Growth rate (in eggs laid) of colonies when workers varied in their bias towards unloading at the top of the nest. No upward bias (random unloading) led to the slowest growth rate. When bees had a slight bias towards moving up (12.5% of the nest height between inspections), the growth rate was also low due to too much honey being deposited where the queen prefers to lay eggs. When bees had a stronger upward bias, however, the rate of egg laying remained at the maximum for much longer. Thus, the extent to which the bees' unloading decisions allow them to make efficient use of their space strongly affects colony growth rate. Open squares, 50%; filled squares, 37.50%; diamonds, 25%; triangles, 12.50%; solid line, random.