Fig. 6. Distribution of the time spent crossing the bottlenecks and the entrances for ants travelling to and from the centre of a 3 mm bridge (for each sector, the results for the nest and source sides of the bridge have been pooled). The dotted lines within the boxplots represent the median, the lower and upper boundaries of the boxes represent, respectively, the 25th and 75th percentiles, while the whiskers extend to the smallest and largest values within 1.5 box lengths. The open circles represent the outliers. N=500 for each box plot.