Abstract
When the movement of one leg of a walking stick insect is interrupted during the power stroke, the force developed by other legs is increased. This effect is shown to occur between all orthogonal nearest-neighbour legs except for the two hind legs. Such effects do not occur between diagonal or next nearest-neighbour pairs. The possible function of these ‘coactivating’ influences is assumed to be to enable the animal to increase the total force propelling the body.