Some Physiological Effects of Ultraviolet Radiation on Honeybees

The beneficial effects of ultraviolet light on higher animals such as chickens, rats, and human beings are now well known. It has been used with great success in the treatment of such diseases of man as tuberculosis of the skin, bones, or viscera, skin diseases of various kinds, rickets, and tetany. Not so well known, perhaps, are the harmful effects of ultraviolet light on various organisms. Bacteria, for example, are readily killed by the so-called ^'middle ultraviolet ^\ that is, by radiations of wave lengths between 210 and 297 m/i ^ ; plants are rather generally harmed by wave lengths shorter than 290 m/x^; and animals, including man, may suffer from serious burns or internal disorders from it under certain conditions. The possibility of finding in ultraviolet light a source of benefit to bees, and consequently to the beekeeping industry, has led to a few investigations on the physiological effect of these rays on honeybees. Probably the first was that performed by two Hungarian workers, Stitz and Beyer, in 1927.^ These workers irradiated one colony of bees and kept another, as nearly identical as possible, as a control. They describe the method and results of their experiment in part as follows: