Figure 18.

A. The “ant hotel” used to test the depth preference of young and old workers (see text for description). B. Initially, each “hotel room” contained 25 young workers taken from the bottom of a mature Pogonomyrmex badius nest, and 25 old workers from the top (each also contained 10 larvae and pupae). Each chamber thus contained 17% of each age group. After allowing 4 days for reassortment, old workers moved upward so that a large proportion of them were recaptured in the upper chambers. The downward movement of young workers was less dramatic.