Honeybee populations around the world have had a hard go of it over the last decade.
A number of factors, some of which are unknown, have caused bees to die off in great numbers. It's a troubling trend since bees pollinate an estimated one-third of the plants that are part of the human food supply.
One of the perils bees face has been causing die-offs for decades but recent reports say humans are making it worse.
Eddie Arruza tells us how some local beekeepers are trying to guard against it.
Eddie Arruza: During the winter months, the dozen beehives on the roof of the Peggy Notebaert Nature Museum are sealed off for the season. Inside, however, they're still full of life.
In the next month or so, as spring sneaks back in to Chicago, the hives will once again be all abuzz. But before the museum's apiarists start to collect honey they'll be looking for any signs of the Varroa mite.
Allen Lawrance, Living invertebrate Specialist at Peggy Notebaert Nature Museum: The Varroa mites population build up throughout the season and if beekeepers aren't diligent about controlling them, it can lead to a total loss of their hives by the fall.
Arruza: At this time of year the dead bees around the museum's hives are part of the natural attrition that happens continuously in every bee colony. But a close look at the bees is required to see if they've become victims of the Varroa mite.
The tiny mite is the vampire of the honeybee world. The reddish-brown, crab-looking parasites attach to bees and their larvae sucking their equivalent of blood and infecting them with several potentially fatal viruses, the most worrisome of which is deformed wing virus.
Lawrance: The bees develop with deformed wings and other deformities. They can’t fly, they get kicked out of the hive and they die shortly after.
Arruza: If the disease becomes widespread in a colony, the implications are enormous for commercial beekeepers who cultivate bees for pollination.
Over the last decade, one-quarter to one-third of colonies in many U.S. beekeping operations have died off, many scientists saying the Varroa mite has been the major factor.
And a recently published study in the journal Science, accompanied by this graphic, concludes human transport of bees across international borders has made the problem a global crisis.
Lawrance: The Varroa mite originally was a parasite of the Asian honeybee. Over time, when the Western honeybee – the honeybee we keep here at the museum – was transported into Asia, this mite jumped from the Asian honeybee to the Western honeybee.
The Asian honeybee evolved with this mite and was able to defend against it. The Western European honeybee does not have this evolutionary history with it, and so the mite is really able to attack it. That mite harbors and transmits this virus.
Arruza: In the Logan Square neighborhood, a beekeping collective called the Chicago Honey Co-Op maintains some hives on the roof of a landscaping business. They too have experienced the Varroa mite.
Sydney Barton, Chicago Honey Co-Op: Varroa is widespread across the entire beekeeping world. It's no less here in the city. It's unavoidable to get Varroa when you buy a new package of honeybees to start a hive.
Arruza: From China to Chicago colonies are being devastated by the mite. But the mite and its destructive diseases were virtually unseen in Western honeybees until about the mid-1980s.
Barton: That's when bees started being imported to the United States, from places like Australia, which at that time didn't have Varroa, but they had no defense against Varroa, either. So, this kind of vicious circle of replacing bees every year began to be started, and exacerbated by the need for commercial beekeepers to travel all over the country, providing pollination services.
Arruza: Thirty years later, the Varroa mite and its impact on bees have become a global crisis which experts say is being made worse by humans. Jana Kinsman is one of the beekeeping hobbyists with the Chicago Honey Co-op who runs a small honey business called Bike A Bee.
Jana Kinsman, Bike A Bee: Colony collapse has a lot do to with the way we grow food in America. There’s a lot of stresses on the modern day beehive, especially a commercial one owned by a commercial apiarist, where they are trucking their bees across the country, their bees have limited forage whenever they got to whichever orchard or field they have to pollinate. Not to mention the pesticides and herbicides in the environments where they often go. These all kind of add up and create this compounding stress.
And then viruses and bacteria and funguses – especially the ones carried by the Varroa mite, that can just kind of leave them weaker.
Arruza: The search for a way to eradicate the Varroa mite has produced some commercial miticides but those need to be applied carefully so as not to contaminate the hive's honey. One very effective and seemingly unusual method of ridding mites from hives is to coat bees in powdered sugar.
Below: Hudson Valley Bee Supply demonstrates how to use a sugar shake to determine the mite level in a honeybee hive.
Lawrance: This causes the honeybees to clean themselves and start grooming, and when they groom, they pick off the mites and they drop off.
Arruza: But the powdered sugar method is labor intensive and not useful in large-scale operations. Another approach that's getting a lot of attention is genetic breeding to produce hygienic bees that can rid themselves of the mite.
Barton: Hygienic behavior means in some cases the bees can detect the Varroa in the larvae of a hive, and remove those larvae before those Varroa are mature and can do damage. In other cases, it means that the hygienic behavior is actually attacking the Varroa. A worker bee will actually attack the Varroa.
Arruza: Purdue university entomologist Greg Hunt is one of the leading experts in developing Varroa-fighting bees. One of his genetic breeding breakthroughs is a bee that chews the legs off of mites.
Studies show the mite-biting bees have twice the survival rate of the non-biting variety.
But the Varroa mite isn't the only danger affecting honeybees. Over the last decade, colony collapse disorder has resulted in more than 10 million beehives lost, nearly twice the normal rate. The cause of this disorder is blamed on numerous factors, some of which are still unknown. But bee enthusiasts remain optimistic.
Kinsman: I have high hopes because there’s a lot of really great genetic breeding programs and a lot of great universities and so many smart people involved. I really hope that it can start combating Varroa and deformed wing and colony collapse and all of these factors.
Arruza: In the meantime, Chicago's small-scale operations are still thriving and there's plenty of evidence for that in the local honey that can be found at some specialty stores. The Peggy Notebaert Museum bees are also well represented in the museum's gift shop.
For “Chicago Tonight,” I'm Eddie Arruza.
More about Varroa mites and bees
The Bee Informed Partnership is a collaboration between research labs, universities, commercial bee growers, naturalists and others, supported by the United States Department of Agriculture and the National Institute of Food and Agriculture. The organization's website offers the latest research and reports, including this video about Varroa mites by the Bee Informed Partnership Lab.
Aug. 2013: Dan Parizek is a “Honeybee Rescuer." With Colony Collapse Disorder destroying some 10 million beehives since 2007, Parizek and others say we can’t afford to lose any more hives. Jay Shefsky has a profile.
Aug. 2013: Dr. Corrie Moreau, Assistant Curator of Insects at the Field Museum, and Karen Kramer Wilson, Living Invertebrate Specialist at The Chicago Academy of Sciences and Peggy Notebaert Nature Museum, share their thoughts on the impact of Bee Colony Collapse Disorder.
Aug. 2012: Beekeeping in Chicago is legal, relatively easy and increasingly popular. We take a look at the largely unseen world of rooftop bees, and the people who care for them.