Fig. 1. Consecutive photographs (from top to bottom) of Aretaon asperrimus male climbing across a gap of 50 mm width between two cardboard footbridges; each picture illustrates one of the sections of the gap-crossing sequence. EFL, exploration and front leg gap-crossing steps; IFM, interval between front leg and middle leg gap-crossing steps; ML, middle leg gap-crossing steps; IMH, interval between middle leg and hind leg gap-crossing steps; HL, hind leg gap-crossing steps.