Honeybee die-off explained?
Seth Williamson
The Globe and Mail
Mysterious die-off of honeybees explained
A virus - first identified in Israel, then seen in Australia - may be
to blame for widespread honeybee carnage in U.S., scientists say
MARTIN MITTELSTAEDT
ENVIRONMENT REPORTER
September 7, 2007
The sudden and mysterious disappearance of honeybees in the United
States over the past year may be due to a virus, according to a new
research paper by an international team of scientists.
The pathogen, called Israeli acute paralysis virus, was detected in
almost all bee hives tested during a survey of hives afflicted by what
has become known as colony collapse disorder. The pathogen is rarely
found in healthy hives.
The discovery will likely help put to rest rampant speculation about
the source of the strange collapse in U.S. bee populations.
Beekeepers in the United States began noticing slight declines in bee
numbers in 2004. The scale of deaths increased dramatically in the
past year, with some apiaries losing up to 90 per cent of their hives.
The workers in colonies of the highly social insects would disappear
without a trace.
The enormous scale of the destruction prompted worry that some new
environmental threat might be killing useful insects. Some speculated
that the missing bees might have become disoriented by the recent
proliferation of radiation from cellphone towers and died while
foraging for nectar. Others theorized that new genetically modified
crops were poisoning the bees.
But scientists who worked on the new research, which is being
published in the current issue of Science Express, now believe the
most likely explanation is a new infectious agent.
"Our extensive study suggests that the Israeli acute paralysis may be
a potential cause of colony collapse disorder," said Ian Lipkin, an
epidemiologist at Columbia University.
The death of bees had caused widespread alarm in the agricultural
industry. Although most people associate bees with honey, the insects
are far more important for their role in pollinating crops. About 90
foods, ranging from apples to cucumbers, depend on bees to ensure that
fruits and vegetables develop.
Any threat to bee numbers could affect the global food supply. An
estimated $2-billion worth of crops in Canada depend on honeybees for
pollination, and about $15-billion in the United States, where the
collapse has already led to difficulties in pollinating crops.
The researchers also found the virus on live bees imported into the
United States from Australia, and in royal jelly samples from China.
Royal jelly is the food bees produce for queens, but it is also sold
as a health food for humans.
The discovery of the virus has raised speculation that the United
States inadvertently allowed it into the country through the import of
Australian bees. This was allowed in 2004, at the urging of the
agricultural industry, to boost the number of hives available for
pollinating high-value crops such as almonds.
The import of the bees coincided with the first reports of unusual
problems in bee colonies.
All the hives infected with the virus either used Australian bees, or
were stored near colonies that imported the insects.
To date, Canada has had no known cases of colony collapse disorder,
said Danny Walker, president of the Ontario Beekeepers' Association.
He said Canada doesn't allow the importation of entire bee colonies
from Australia, although it does allow apiaries to buy individual
queens, which are then seeded into domestic hives.
Scientists who discovered the virus, and analyzed genes of
micro-organisms found in bees, said they do not know if the pathogen
itself causes colonies to die off, or whether it weakens the bees and
makes them more susceptible to pesticides, poor nutrition and
parasitic mites.
The virus was first described in Israel in 2004, leading to its name.
Researchers there noted that infected bees - which exhibited shivering
wings and paralysis - would die just outside their hives.
One perplexing finding is that bees in Australia don't seem to be
affected by colony collapse disorder. The researchers speculated the
reason might be that bees there are not infected with varroa mites,
which are found throughout in North America. The mites suppress the
immune system of bees, making them more vulnerable to other threats.
Lee Chichester
At a friend's house in Dugspur last weekend, we saw lots of migrating
nighthawks foraging over his pond. Last night, across the road from
our house, there is a hayfield, above the Rock Castle CCC Cabins
(Rock Castle Gorge) and there was another flock of them zipping and
zooming around at dusk.
wonderful sight to see.
Lee Chichester