Fig. 2. Where ants search for an absent feeder that is normally placed between two cylinders. Results pool data from two experiments in which the starting pen was either 40 cm or 100 cm from the feeder. (A) Tests with training cylinders of equal size. (B) Tests in which one cylinder is smaller and one larger than in training. Here, and in the remaining figures, the position of the feeder predicted by the snapshot is shown by a white circle. The contour plot represents the percentage of time the ants spent in each area; the darker the grey, the higher the percentage. The darkest area represents 9.8% of the total search in the training condition (N=71 paths) and 3.81% in the test condition (N=93 paths). The mean X positions (see Materials and methods) of the two distributions differ significantly (Wilcoxon two-sample test; P<0.001, t=8.04, d.f.=162).