Abuzz over Bees

New theory on yellow rain

For the past two years, the U.S. Government has been urgently seeking to convince the world that the Soviet Union has been guilty, in Afghanistan and Southeast Asia, of violating international bans on chemical warfare. The alleged weapon: "yellow rain," a lethal spray of poisons. The Soviets have denied the charge, and a United Nations panel was unable to confirm it. Now, to the considerable embarrassment of U.S. officials, a group of respected scientists has offered a new theory. Said Harvard Biochemist Matthew Meselson last week at a meeting of the American Association for the Advancement of Science: "There is good evidence that yellow rain is bee excrement."

Meselson, an authority on chemical weaponry, based his hypothesis on studies of tiny samples of yellow rain collected in Southeast Asia. Electron microscopy disclosed that the samples consisted primarily of pollen husks from tropical plants favored by honeybees. Meselson then compared the substance with bee droppings collected around Harvard and found them remarkably similar, right down to the presence of a bee hair.

The State Department quickly ridiculed Meselson's theory as "the great bee caper" and stated that its scientists had already rejected such natural explanations. Spokesman Alan Romberg pointed out that one sample of a yellow raindrop weighed 300 mg, which, he said, "is certainly more than a bee could drop." The greatest flaw in Meselson's theory, Romberg continued, is that it fails to explain why yellow rain contains fungal poisons, or mycotoxins, which are present in doses large enough to kill a man, let alone a bee. The Government contends that mycotoxins have been found in the bodies of Asian victims of Soviet spraying and in the blood and urine of survivors.

Meselson was unimpressed by these arguments. Because honeybees do not defecate during the winter or rainy seasons, he explains, a large volume of feces accumulates over these long periods. Meselson admits, however, that the origin of the toxins is not easily explained, though he noted that the poison might be produced by fungi that often grow on bee excrement. In any case, Meselson says, the bee theory "opens up the realm of natural explanations for yellow rain in a way not previously done." The problem for the Government was that with international relations at stake, there was still so much room for scientific controversy. qed This file is automatically generated by a robot program, so viewer discretion is required.