Fig. 2.

Experimental results. (A) Probability density function (PDF) of the distance between ants’ attachment point and position of chain tip at the moment of joining. Negative values represent instances in which ants joined beyond the tip of the structure, while positive values indicate joining positions along the chain. The area outlined in red indicates 90% of the data, and the dashed line indicates the median of the distribution. (B) Probability density function (PDF) of the distance between ants’ leaving position and position of chain tip at the moment of leaving. The blue dashed line indicates the mean of the distribution. (C) Results from the linear mixed-effects model, showing the relative effects of predictors on the probability of observing an ant joining the chain. (D) Survival analysis of the time spent by ants in the structure during chain formation. Survival curves are plotted using predictions extracted from the Cox model for the first (orange) and fifth (purple) quantiles of each predictor.