Honey, Who Shrunk the Bee Population?

The story on the mysterious die-off of honey bees is in
today's media. Here's an article in The Independent (UK) Sent
in by Andy Davidson:
Species under threat: Honey, who shrunk the bee population?

Across America, millions of honey bees are abandoning their
hives and flying off to die, leaving beekeepers facing ruin
and US agriculture under threat. And to date, no one knows
why.

Michael McCarthy reports

THE INDEPENDENT
Published: 01 March 2007
It has echoes of a murder mystery in polite society. There
could hardly be a more sedate and unruffled world than
beekeeping, but the beekeepers of the United States have
suddenly encountered affliction, calamity and death on a massive
scale. And they have not got a clue why it is happening.

Across the country, from the Atlantic coast to the Pacific,
honey bee colonies have started to die off, abruptly and
decisively. Millions of bees are abandoning their hives and
flying off to die (they cannot survive as a colony without
the queen, who is always left behind).

Some beekeepers, especially those with big portable
apiaries, or bee farms, which are used for large-scale pollination
of fruit and vegetable crops, are facing commercial ruin -
and there is a growing threat that America's agriculture
may be struck a mortal blow by the loss of the pollinators.
Yet scientists investigating the problem have no idea what
is causing it.

The phenomenon is recent, dating back to autumn, when
beekeepers along the east coast of the US started to notice the
die-offs. It was given the name of fall dwindle disease,
but now it has been renamed to reflect better its dramatic
nature, and is known as colony collapse disorder.

It is swift in its effect. Over the course of a week the
majority of the bees in an affected colony will flee the hive
and disappear, going off to die elsewhere. The few
remaining insects are then found to be enormously diseased - they
have a "tremendous pathogen load", the scientists say. But
why? No one yet knows.

The condition has been recorded in at least 24 states. It
is having a major effect on the mobile apiaries which are
transported across the US to pollinate large-scale crops,
such as oranges in Florida or almonds in California. Some have
lost up to 90 per cent of their bees.

A reliable estimate of the true extent of the problem will
not be possible for another month or so, until winter comes
to an end and the hibernating bee colonies in the northern
American states wake up. But scientists are very worried,
not least because, as there is no obvious cause for the
disease as yet, there is no way of tackling it.

"We are extremely alarmed," said Diana Cox-Foster, the
professor of Entomology at Penn States University and one of
the leading members of a specially convened colony-collapse
disorder working group.

"It is one of the most alarming insect diseases ever to hit
the US and it has the potential to devastate the US
beekeeping industry. In some ways it may be to the insect world
what foot-and-mouth disease was to livestock in England."

Most of the pollination for more than 90 commercial crops
grown throughout the United States is provided byApis
mellifera, the honey bee, and the value from the pollination to
agricultural output in the country is estimated at $14.6bn
(?bn) annually. Growers rent about 1.5 million colonies
each year to pollinate crops - a colony usually being the
group of bees in a hive.

California's almond crop, which is the biggest in the
world, stretching over more than half a million acres over the
state's central valley, now draws more than half of the
mobile bee colonies in America at pollinating time - which is
now. Some big commercial beekeeping operations which have
been hit hard by the current disease have had to import
millions of bees from Australia to enable the almond trees to be
pollinated.

Some of these mobile apiaries have been losing 60 or 70 per
cent of their insects, or even more. "A honey producer in
Pennsylvania doing local pollination, Larry Curtis, has gone
from 1,000 bee colonies to fewer than eight," said
Professor Cox-Foster. The disease showed a completely new set of
symptoms, "which does not seem to match anything in the
literature", said the entomologist.

One was that the bees left the hive and flew away to die
elsewhere, over about a week. Another was that the few bees
left inside the hive were carrying "a tremendous number of
pathogens" - virtually every known bee virus could be
detected in the insects, she said, and some bees were carrying
five or six viruses at a time, as well as fungal infections.
Because of this it was assumed that the bees' immune
systems were being suppressed in some way.

Professor Cox-Foster went on: "And another unusual symptom
that we're are seeing, which makes this very different, is
that normally when a bee colony gets weak and its numbers
are decreasing, other neighbouring bees will come and steal
the resources - they will take away the honey and the
pollen.

"Other insects like to take advantage too, such as the wax
moth or the hive beetle. But none of this is happening.
These insects are not coming in.

"This suggests that there is something toxic in the colony
itself which is repelling them."

The scientists involved in the working group were surveying
the dead colonies but did not think the cause of the deaths
was anything brought in by beekeepers, such as pesticides,
she said.

Another of the researchers studying the collapses, Dennis
van Engelsdorp, a bee specialist with the State of
Pennsylvania, said it was still difficult to gauge their full
extent. It was possible that the bees were fleeing the colonies
because they sensed they themselves were diseased or
affected in some way, he said. This behaviour has been recorded in
other social insects, such as ants.

The introduction of the parasitic bee mite Varroa in 1987
and the invasion of the Africanised honey bee in 1990 have
threatened honey bee colonies in the US and in other parts
of the world, but although serious, they were easily
comprehensible; colony collapse disorder is a deep mystery.

One theory is that the bees may be suffering from stress as
beekeepers increasingly transport them around the country,
the hives stacked on top of each other on the backs of
trucks, to carry out pollination contracts in orchard after
orchard, in different states.

Tens of billions of bees are now involved in this
"migratory" pollination. An operator might go from pollinating
oranges in Florida, to apples in Pennsylvania, to blueberries in
Maine, then back to Massachusetts to pollinate cranberries.

The business is so big that pollination is replacing
honey-making as the main money earner at the top end of the
beekeeping market, not least because in recent years the US has
been flooded with cheap honey imports, mainly from
Argentina and China.

A typical bee colony, which might be anything from 15,000
to 30,000 bees, would be rented out to a fruit grower for
about $135 - a price that is up from $55 only three years
ago. To keep the bees' energy up while they are pollinating,
beekeepers feed them protein supplements and syrup carried
around in large tanks.

It is in these migratory colonies where the biggest losses
have been seen. But the stress theory is as much
speculation as anything else. At the moment, the disappearance of
America's bees is as big a mystery as the disappearance of
London's sparrows

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