Leg-to-body geometry determines eyestalk reactions to substrate tilt. Substrate orientation in Spiny Lobster IV

The effect of oscillatory movement of single legs (about C-B axis) on compensatory eyestalk reactions and on leg counterforce as normally produced by substrate tilt has been investigated with the legs at different states of flexion (M-C joint) and leg-to-body orientation (T-C joint). Eye response and force reaction released by standard C-B movement increase with increasing angle of M-C (Figs. 2, 4) and decrease with decrease of T-C angle (Fig. 3). The effects demonstrate a multiplying influence of M-C signal and T-C signal on C-B signals. The stump of an autotomized leg releases eye responses of similar magnitude to unimpaired single legs (Fig. 5). The data are discussed in relation to neurophysiological findings and with respect to the geometrical implications for the mechanism of substrate orientation