Fig. 2. Variation of the silking force (A), fibre diameter (B) and silking stress (C) during the silking process at 1 mm s^-1 of an anaesthetized spider. The shaded zone spans the period during which the spider was exposed to the CO₂ flow. The three regions I, II and III, referred to in the text are indicated. The samples whose tensile properties were measured are numbered from 1 to 8 and their positions along the silking process are indicated at the bottom of each panel. F_M(I), maximum force in region I; F_m(I), minimum force in region I; F_M(II), maximum force in region II; F_m(III), minimum force in region III.