Researchers Fight to Keep Maryland's Best Pollinators
|Maryland's bees have been under siege by
two destructive parasites. (Photo courtesy National Human Genome Research Institute)
By Lisa D. Tossey
Thursday, March 11, 2004
If your garden has been
a little quieter the last few springtimes, there’s good reason. Maryland’s honeybees have been
decimated by parasitic mites over the last 15 years, pushing beekeepers and
researchers to find ways to keep the bees buzzing and raising questions
about the possible regulation of genetically modified bees and their honey.
Bee colonies in Maryland have suffered huge die-offs as
a result of the invasion of two parasites, the tracheal mite (Acarapis
woodi) and the ominous sounding Varroa destructor mite,
said Jay Evans, a research entomologist at the U.S. Department of
Agriculture’s Bee Research Laboratory.
Of the two mites, Varroa, which
feeds on the blood of developing larvae and adult bees, has been the more
destructive. “It lives on a bee like a tick on a dog,” said Jerry
Fischer, state apiary inspector for the Maryland Department of Agriculture.
The mite’s feeding habits weaken the bees, leaving them susceptible to
infections and disease, he said.
Evans and other scientists at the Bee Research
Laboratory in Beltsville, Md., have been examining the biology of such
honeybee parasites, diseases and pests to develop biological, chemical and nonchemical methods of control.
In early January the researchers were given a vital
new tool: A team of U.S. scientists completed a draft of the honeybee
genome and posted the sequence in an online database. It was the first
genome of a domesticated animal to be completed.
Evans said having the genetic sequence available as a
research tool will be helpful, allowing scientists to test the importance
and function of a single gene by “silencing it.” He expects researchers
will largely use the genome to influence breeding programs and says although
he isn’t aware of any current work, the creation of genetically modified
bees might be a possibility in the future.
A recent report from the Pew Initiative on Food and
Biotechnology titled “Bugs in the System?” states that there may be public
health and agricultural benefits from genetically modified insects, but
warns that clear oversight by the government is lacking.
“The $64,000 question is, 'Who will regulate?' ” said Dan DiFonzo, deputy director of media relations for the initiative. “The
government agencies need to get together to sort it out. We’re trying to
jump-start the debate.”
The Importance of Bees
Bees are agricultural workhorses. The U.S. Department of Agriculture
estimates that 80 percent of crop pollination by insects is accomplished by
In Maryland, the bumbling aviators are responsible each year for
pollinating crops valued at more than $40 million, Fischer said.
This makes them invaluable to area farmers, who have relied on wild
swarms to pollinate their crops since the bees were first imported from
Europe nearly 400 years ago.
“Farmers would walk the fields and keep count of how many bees they saw
in 25 steps,” Fischer said. “Then 12 years ago, our office
received many calls asking, ‘Where are the bees?’ ”
The Spread of Pests
Evans said the mites spread throughout the country
almost overnight and have “effectively erased the genetic population of wild
He estimates that less than 10 percent of the wild U.S. bee population remains.
|Beekeepers have been using several
different control methods to protect their domestic hives. (Photo courtesy National Human Genome Research Institute)
At the peak of the outbreak, Maryland lost nearly 99
percent of its feral colonies, Fischer said. Farmers were forced to turn to beekeepers for
help, renting domesticated colonies to pollinate their crops and orchards.
Fischer, who oversees the nearly 1,000 beekeepers registered in Maryland,
said roughly 4,500 colonies are rented out to
agriculture each year. Because of different growing seasons for the state’s
diverse crops, such as apples, pears, cucumbers, melons and pumpkins, each
colony serves about five different “contract pollinations” a year.
So far, these domestic populations have been somewhat protected through
the keepers' use of mite screens and miticides, and by researchers'
development of disease-resistant strains of bees.
“Keepers have managed to keep the bees going at some level,” says Evans.
But those domestic colonies have been hit hard as well. Davis
Morris, past president of the Maryland State Beekeepers Association, said
the introduction of mites caused beekeepers to lose 50 percent to 60 percent of
their hives between 1995 and 1996 – a loss he says they haven’t fully
recovered from. In the past two decades, the number of managed hives
statewide has dropped from about 25,000 to 10,000.
“It’s been difficult,” said Morris, who keeps bees as a
hobby and now serves as president of the Bowie-Upper Marlboro Beekeepers
Association. “It’s very difficult to just keep a hive alive without chemical
Hope for the Future
For now, all are cautiously optimistic about the future
of Maryland’s bees, noting that there are several strong research programs
in the country that are devoted to honeybee survival.
In addition, Fischer has seen mite levels drop in Maryland over the
past five years. “They’ve been a major problem, but are getting better,” he
Although he can’t pinpoint exactly why mite populations
have declined, Fischer points out that they're unlikely to kill off all the
“Fortunately, parasites need a host," he said. "No parasite has ever
eliminated its host, because if it does, it also dies."
2004 University of Maryland
Philip Merrill College of
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