Figure 2. When forced to move across different surfaces, colonies of the ant W. auropunctata formed trails with an angle ρ' closer to the optimum ρ (in 15 out of 18 trials) than to the angle α they would have followed if moving to the food source on a straight line.

Given for each surface combination are α, ρ and ρ' of each of three colonies (bars = median, whiskers = minimum and maximum). ρ varied largely due to colony differences in walking speed.