Fig 5. Relationship between peak normal force and corresponding shear force along the (projected) axis of the leg for individual steps.

Filled circles denote steps in which the arolium made visible surface contact, whereas steps with detached arolium are marked with open circles. Lines show standardised major axis regressions on both types of steps. In most steps where the adhesive pad made contact, the legs were pulling, whereas steps without visible arolium contact occurred mostly when legs pushed. The drawings illustrate the direction of the normal forces (F _N) and shear forces (F _S) and the presence or absence of adhesive pad contact (black or white filling of the pad).