Alternative Tasks of the Insect Arolium with Special Reference to Hymenoptera

Apterigous terrestrial insects walk over relatively flat surfaces the radii of curvature of which are not less in size than their bodies or legs. They grasp at the surface with claws of several extremities, clasping the foothold between opposite legs. Without any sticky pads, machilids run extremely fast on stones and rocks of an arbitrary inclination. Hook-like interlocking mechanisms of much smaller dimension also are found in secondary legs of caterpillars (Nielsen and Common, 1991; Hasenfuss 1999).