Animal perception of x-rays.

Daphnia magna, when irradiated by x rays in the presence of red light, swims downward, indicating a preferential stimulation of the nauplius eye. A lack of effect on other behavior patterns indicates that no significant change occurs between the yellow and blue receptors of the compound eye. The structure and function of these two eyes are reviewed. Photographic records of irradiated daphnids indicate that too little fluorescence exists in the organisms to account for the response. Experiments with redox-poisoning compounds, however, reveai that the effect of x rays can be duplicated with reducing compounds. No experiments were performed to test whether or not the x rays had a direct bieaching effect on the visual pigments. Miscellaneous other factors such as heat are eliminated as possible mechanisms. (auth)