TRACKING OF BLUE LIGHTS BY HYPERIID AMPHIPODS

Hyperiid amphipods (Brachyscelus, Phrosina, Phronima) are attracted to light from a blue light-emitting diode. They track a moving LED by ro tation and translational movements. These keep the image of the LED in the antero-dorsal part of the field of view, which corresponds to the upper part of the retina of the ventral eye, not the specialized dors al eye. The tracking system measures the angle of the target direction from this fixation centre, and converts it into a corrective motor re sponse in 0.2-0.4 s. We believe this response is normally concerned wi th attraction to and pursuit of luminescent organisms.