PULLMAN, Wash. (AP) -- There's a lot of buzz at Washington State University over work to develop the first sperm bank for honeybees.

Entomologist Steve Sheppard and his crew are using liquid nitrogen to preserve semen extracted from the industrious insects that pollinate much of the nation's food supply but face environmental threats. The goal is to preserve and improve the stock of honeybees and to prevent subspecies from extinction.

"We do that frequently with horses and cattle and chickens," said Susan Cobey, a research associate on the project. "Finally, we have the capability to do it with bees."

Honeybees are serious business. Washington's $1 billion apple crop, for instance, needs 250,000 colonies of bees each year to pollinate the orchards. California almond growers need 1 million colonies per year to pollinate their crop.

As a result, there is incentive to find ways to strengthen bee colonies.

But the problem has been storing bee sperm for the long term. One of Sheppard's graduate students, Brandon Hopkins, came up with the solution of preserving it in liquid nitrogen tanks on the Pullman campus. It can be preserved this way for years. The bee industry has provided funding so WSU researchers can buy the tanks and other equipment they need.

Honeybees face a lot of challenges in the modern world. They can be attacked by invasive mites, exposed to disease and pesticides, or faced with a substandard diet because of modern practices that discourage farms from planting a variety of crops. These threats can combine to cause colony collapse disorder, in which the worker bees disappear and an entire hive is doomed, Sheppard said.

One way to fight colony collapse is to create smarter, stronger bees, he said. That's where the work being done at WSU comes in. Scientists can use the semen to selectively breed honeybees to improve the subspecies and make it more resistant to dangers.

There are 28 subspecies of honeybees in the world, but the U.S. since 1922 has restricted the import of live honeybees to protect local bees from mites and other dangers.

In an effort to improve the local stock, the U.S. Department of Agriculture in 2008 granted Washington State a permit to import honeybee semen for breeding purposes, Sheppard said.

To meet the goals of beekeepers across the various climate zones of the U.S., Sheppard and his colleagues identified three subspecies for import. The desired bees come from Italy, the eastern Alps and the mountains of the nation of Georgia, he said.

The Italian bees, for instance, are prized because they reproduce quickly and provide maximum pollination for early-blooming crops like almonds, Sheppard said. By contrast, beekeepers in colder climates want bees that delay reproducing, so a late cold snap does not kill an entire brood, he said. That's where the bees from the Alps and Georgia are valuable.

The semen from the desirable bees is extracted and frozen, Sheppard said.

"We are able to freeze and thaw well enough to make a whole generation of queens," Hopkins said.

The new sperm bank -- which the scientists prefer to call a "germplasm repository"-- also could help preserve imperiled subspecies, Cobey said.

"This gives us huge capabilities to preserve stock," Cobey said. "We have honeybees globally that we are losing."