Abstract
We have been investigated how to use protists as living micromachines by controlling their behavior using their taxis. Because of the difficulty of attaching tools on protist such as Paramecium, we are now investigating the applicability of the water flea for bio-micromachine. Water fleas are small crustacean and they wear outer shells as external skeletons. Therefore, we can attach operational tools on the shell by chemical adhesion. In our former studies, we succeeded to control Daphnia magna's motion by illuminating the blue LED light to guide the swimming direction using their strong positive phototaxis. We also succeeded to destroy a poly vinyl balloon by using a needle attached on the Daphnia's back. This operation, however, was limited on the water surface because we used a wing float to stabilize Daphnia's posture. In our previous report, we tried to make balloon destroy into the water. The results were that the needle installed Daphnia could not puncture the balloon because collision shock of the Daphnia in the water was too weak. We assumed that the weak collision shock might relate to the Daphnia's intermittent swimming style. Therefore, in this study, we investigated the alternative candidate, Ostracoda. Ostracoda swims continuously, and the relative swimming speed is higher than that of the Daphnia. Ostracoda also have strong positive orientation phototaxis to the blue light. So we can apply the Daphnia's motion control method to the Ostracoda. We succeeded to guide Ostracoda along the star-shaped target route. The investigation results of the basic motion control property showed that the maneuverability of the Ostracoda is lower than the Daphnia and we had to figure out the control method for Ostracoda.
