Figure 1.

(a) Schematic of a tribometer, modified from Murarash and Varenberg [24]. (b) A representative force–distance curve obtained for a male in contact with a female's elytra. Distance 0 is defined as the point at which the motion starts and is a relative measurement. Inset images illustrate the posture of the male corresponding to the curve sites below. Grey arrows, pointing diagonally left downwards, indicate the instants of leg sliding.