MOTOR BEHAVIOR OF PREY DURING 1ST STEPS OF FOOD CAPTURE BY ACTINOPHRYS-SOL

Samples of Actinophrys sol, taken 34 h after feeding, were supplied ag ain with food, a flagellate Chlorogonium elongatum or a ciliate Tetrah ymena pyriformis. First stages of the prey-predator interactions could then be noticed, although the heliozoa were incapable of ingesting mo re food. The prey moved randomly and was not attracted by heliozoa at a distance, nevertheless it accumulated around them in large numbers. by a trap mechanism. The flagellates were entrapped by adhesion to the bottom underneath Actinophrys cells and to the distal segments of axo podia that touch the substratum. Aggregations of the ciliates were dyn amic and kept together by the changes of swimming direction, i.e. by c hemokinesis.