X-ray induced behavioral reactions and detection mechanisms in the Shrimp

Red Ghost Shrimp, Callianassa californiensis, were shown from behavioral and electrophysiological studies to respond to ionizing radiation. When exposed to x-rays at 52 R/sec, the majority of intact animals could detect and avoid further irradiation by escaping into a shielded section of the test chamber. Animals continued to display escape responses after removal of eyestalks and antennae. Significant avoidance activity also occurred with partial-body exposure and indicated the existance of a radiation-sensitive receptor on the abdomen. Electro retinograms elicited by β- and x-radiation sources corresponded closely with the waveforms produced by visible light stimulation. Electroantennograms were recorded from isolated antennules following stimulation with glutamic acid, β- and x-radiation. Biphasic on-off phases were recorded with an intermediate phase present during the longer duration exposures. Similarly, bioelectrical potentials were recorded from swimmeret preparations with exposure to β-and x-radiation. The electrophysiological evidence indicates that the eye, antennules, and possibly chemoreceptors on the abdominal segments serve as routes for detection of ionizing radiations. (author)