VOA标准英语2014--本地蜜蜂可能帮助拯救农作物（在线收听）

Native Bees May Help Save Crops 本地蜜蜂可能帮助拯救农作物

BELTSVILLE, MARYLAND—

In June, U.S. President Barack Obama called for a federal strategy to promote the health of bees and other pollinators that have been declining. The honeybee has been waning due to parasites, disease, pesticides and farming.

Wild bees may be used to take over their role as crop pollinators. Before that can happen, though, scientists first need to learn a lot more about wild bees, said biologist Sam Droege, who is pioneering the first national inventory on native bees.

To most of us, a bee is just a bee, but not to Droege.

 “They’re beautiful to look at under a microscope,” he said at his research laboratory in Beltsville, Maryland, between Washington and Baltimore.

Pioneering research

Four years ago, Droege began his pilot project surveying native bees for the U.S. government’s Geological Survey. He sorts them in pizza boxes, which he uses for storage. He says scientists know a lot about honeybees -- which produce honey and pollinate a third of U.S. crops - but very little about wild bees, which pollinate 75 percent of wild plants.

“They don’t produce honey. They don’t have a barbed sting. They’re not aggressive. Some like sandy soils, some like thick grass; some are only nesting in woods,” said Droege.

If the honeybee population continues to decline, Droege said wild bees have a better chance of survival because they are solitary.

“One of the reasons they’re more robust than honeybees is that they nest individually. One female makes one nest at a time. At the end of the year, the female dies and the whole system restarts so you don’t accumulate as many diseases,” he said.

Building inventory

Droege said his survey is only the first step in a long process to learn about wild bees. He said once scientists have an inventory, they can study their habits and use them to pollinate crops. He estimates there are 4,000 types of native bees in North America - 400 yet to be named.

“They haven’t been scientifically described. We might know that they’re different or they’re a new kind of species,” he said.

Most of Droege’s inventory comes from 20 U.S. forest sites across the country. He also travels to find bees, and doesn’t have to go far to discover some just outside the building housing his laboratory.

“I have no idea what I’m going to find each time. In just this region alone, there’s over 400 different species,” said Droege.

Gentle insects

He said the insects - some as tiny as a grain of rice - are on the ground, but people don’t notice them.  

“Most people have no idea that their lawns are nothing but grass interspersed with bee nests," said Droege.

Since some bee species look remarkably similar, Droege examines each one through a microscope and documents them with high-resolution photos.

“And the differences are real subtle, slightly different sizes and shapes, a little bit more color here than there, differences in the hair patterns,” he said.

Droege says his survey will show whether some species of wild bees are declining or flourishing.  He says that so far, scientists don’t know the answer, but he thinks most are doing just fine.