The influence of substrate contact on gravity orientation

Summary Tilting of the animal with respect to gravity results in compensatory eyestalk movements and in leg counterforce reactions which vary with the number and sequential position of legs touching the body-fixed substrate board (Figs. 2, 3). The gravity response is reduced with increasing number of legs touching the substrate. The results fit an interpretation that the weight of the substrate input interacting with gravity signals results from superposition of the weighted effects of the single legs involved (Figs. 2, 4).Acknowledgements are due to the Max-Planck-Institut (D. M. Neil, N. Scapini) and to the Carnegie Trust (D. M. Neil) for financial support. We want to thank renate Alton for her co-operative help.