As reported by Kirk Johnson of the New York Times, a somewhat odd pairing of entomologists and military scientists has pinpointed likely culprits: a fungus and a virus, both of which flourish in cool, wet environments. While scientists aren't certain, they believe the fungus and virus work together to hamper the insect's digestive system. Each is relatively harmless on its own, Johnson says, but their combination is deadly.
The findings by Army scientists in Maryland and bee experts in Montana are outlined in a paper published by the Public Library of Science's PLoS One.
The honeybee die-off -- populations in the United States alone are believed to have dropped 20 percent to 40 percent -- was a source of growing concern because of the vital role bees play in the food chain. As a 2007 "60 Minutes" report on the die-off noted, the bees are "crucial to the production of one-third of the foods we eat" because of their role in pollination.
The phenomenon of entire beehives disappearing has come to be known as colony collapse disorder.
Informed speculation previously blamed a host of factors for the die-off, such as pesticides and the cell-phone-driven increase of radiation in the atmosphere.
Though the identification of a cause is encouraging, scientists still find reason for concern.
"I hope no one goes away with the idea that we've actually solved the problem," Jeff Pettis of the U.S. Department of Agriculture's Agricultural Research Service told MSNBC. "We still have a great deal of research to do to resolve why bees are dying in the U.S. and elsewhere."