VOA标准英语2010年-Honeybees Still Disappearing in the US（在线收听）

Honeybees, which are very important to agriculture, continue to disappear at alarming rates in the United States. And the cause of this disappearance is still elusive. While at least one recent study seems to point to pesticides as the problem, the US Agriculture Department has also found parasites causing general weakness among bee colonies. 

Beekeepers around the country are struggling to keep their honeybees alive.  According to the US Department of Agriculture the losses around the country are between 50 and 90 percent.

"Our losses for the last couple of years have averaged better than 60 percent a year," David Hackenberg stated. He is one of the largest beekeepers on the East Coast of the United States. He has worked with bees for the last 48 years. He blames the disappearance of his bees on pesticides.

"The farmers, the horticulture people, the gardeners are pouring out all kinds of chemicals out here on the field, going in our soil and the stuff is coming back up in the plants," he said. "The unfortunate thing about this is that if this stuff is getting in the plants is also getting in the food."

Hackenberg says the problem is especially evident in the wax the bees produce. "The wax absorbs most of the stuff.  The wax is just full of pesticides," he said.

During the winter Hackenberg moves most of his bees to Florida.  As the spring comes in, he starts traveling north towards Pennsylvania with the bees, renting them to farmers, for weeks at a time, to pollinate all types of crops.  About a third of the U.S. food supply, in fact, comes from crops that are pollinated by insects. "Our bees move about 12,000 miles (19,000 kilometers) a year on the back of a truck," he explained.

Bees fly free during the day and then return to their hive at night.  That is when Hackenberg packs them back into the trucks and moves on to the next crop.

The mysterious disappearance of bees began about seven years ago in the U.S. and Europe.  Eventually the phenomenon was labeled "colony collapse disorder," or "CCD."  But while they now have a name for it, scientists still do not have a clear explanation for the problem.

At the U.S. Agriculture Department's bee research lab in Maryland, Jeff Pettis is the research leader.

"We think there is some group of interaction between things like poor nutrition, pesticide exposure and pathogens.  So I would point to those three things as adding enough stress to the colony that then that colony is susceptible to the pathogens to the viruses and bacteria."

Pennsylvania State University recently released the results of a large study on honeybees.  It found an average of six different pesticides in the honey, wax and dead bees that were studied.  Some samples had more than 80.  Pettis participated in the research. "What we found was that there were a variety of pesticides that were in the pollen, the wax and the bees themselves," he says, "so there was a lot of exposure."

While most studies are designed to show the effects of one pesticide at a time, research into combinations of pesticides is just beginning.

"Penn State, the lab here, several labs around the country are beginning to combine different pesticides together and look at the synergy of it as it goes on," Pettis said.

Pettis says no research has yet shown enough evidence to declare pesticides as the only reason the bees are disappearing.  He says the bee colonies that have collapsed show high disease levels, but scientists have not been able to explain how that happens. "The only clear signal that we see is that when the bees die they have high levels of viruses and pathogens," he explained.

Research indicates that poor nutrition among bees is mostly due to large fields of single crops, which leave the bees without enough variety in their diet. There are other theories as well, but all of them seem to point in the same direction as David Hackenberg's outlook:

"I don't think the future is good," Hackenberg says, "It's going to take a long time to clean up our environment.  We contaminated our environment to the point that is going to take a long time to reverse it."

Report narrated by Elizabeth Lee