Why are the bees disappearing?

  • Article by: Matt McKinney
  • Star Tribune
  • April 24, 2007 - 11:08 PM

Researchers nationwide are trying to solve a growing agricultural mystery: Where are all the bees?

While picnickers may cheer their demise, the rapidly shrinking bee population threatens the pollination and survival of a multitude of commercial crops.

A hint of the problem first arose five months ago in Florida where beekeepers said they found whole hives abandoned by adult bees who left behind food and bee larvae, the young that develop inside the hive.

"We're at a tipping point but we don't know what's caused the tip," said Kevin Hackett, a bee expert with the U.S. Department of Agriculture.

Minnesota beekeepers, whose hives are still in hibernation, will learn in coming days how hard they've been hit. The prospect of losing a significant number of colonies has some local beekeepers worried.

The problem now has a name -- colony collapse disorder -- but no explanation. It concerns one type of bee, the European honeybee, or apis mellifera. Bumblebees and any of the 1,500 other species of bee found in the United States are not in danger, but neither are they a replacement for the honeybee.

It's the nation's workhorse when it comes to pollination, handling the work necessary to create commercial crops of apples, blueberries, almonds, cranberries, melons and other crops. (Some crops, such as corn, Minnesota's largest by acreage, are self-pollinating.)

Any treatment for colony collapse disorder is confounded by its many possible causes: pathogens; deadly mites; lack of genetic diversity in the bees; widespread pesticide use and even urban sprawl that spreads homes and streets across wild fields of clover, alfalfa and flowers, all sources of bee food.

It may simply be a combination of all of these things, said Hackett.

The problem, though more severe this year, is not entirely new. Beekeepers for years were reporting 5 to 15 percent losses in their hives, according to Hackett. That climbed to 35 percent in the 1990s as the presence of a deadly mite known as the Varroa spread among bee populations. Then, about five months ago, some beekeepers began reporting 80 percent to 90 percent losses.

The numbers are considered inexact because they're based on beekeepers' estimates rather than a scientific survey.

'What did I do wrong?'

Establishing such a survey was one of the goals announced by a group of 60 scientists from around the country who met at USDA headquarters in Maryland on Monday for a two-day summit on colony collapse disorder. The group laid out what's known so far with a plan to draft a list of specific research that needs to be done, Hackett said.

The meeting follows testimony March 29 before the House Subcommittee on Horticulture and Organic Agriculture on the scope of the problem from several bee experts, including Minnesota beekeeper David Ellingson. A past president of the Minnesota Honey Producers and a lifelong beekeeper, Ellingson, of Ortonville, Minn., testified that with a 60 percent loss of his bees in recent months he has reached the "lowest point in my beekeeping life."I truly felt that we had done everything right this year," he told the subcommittee. "But then you wake up at 2 in the morning and lie there wondering, what did I do wrong?"

Ellingson, like many Minnesota beekeepers, ships his bees by truck to crops in warmer climates during the winter months. His bees went missing in California and he had to cancel a contract.

Most of the losses reported so far have been in California, Florida, Oklahoma and Texas.

Parasitic mites

The problem is severe, but it hasn't affected the marketplace yet, according to a spokeswoman for the National Honey Board. "Nobody is harvesting any honey right now so it's really too soon to know how it might affect the price," said Lisa Jager, a spokeswoman for the Honey Board. The board has set aside $158,000 in recent weeks to university researchers to study the problem.

Researchers who plan to tackle the problem include Marla Spivak, a researcher and bee expert at the University of Minnesota. Spivak, who attended the two-day USDA summit, has studied the Varroa mite, which over the past 20 years has become a major threat to commercial honeybees. First discovered in the United States in 1987, the mite weakens the bee's immune system. It kills off most bee colonies within a year or two after invading. Beekeepers use pesticides to control the mites, but Spivak has studied ways to breed honeybees that are resistant to it.

"Bees have been dying like crazy just from these parasitic mites alone," Spivak said.

Many researchers, including Spivak, widely dismissed a report that cell phone towers and radio waves may be to blame for the bee's disappearance. The theory has percolated throughout the Internet, despite repeated denunciations by bee researchers.

Scientists who spoke at the conference said a similar problem appeared among bee colonies in the 1960s, according to Kim Kaplan, a USDA spokeswoman. "They were never able to define a cause, and it disappeared," she said.

Matt McKinney • 612-673-7329 •

© 2018 Star Tribune