[Pollinator] Signs of Decline: First Honeybees, Now Bumblebees

[Scott Black]

<http://www.washingtonpost.com/?nav=pf>
washingtonpost.com


Signs of Decline: First Honeybees, Now Bumblebees

By Adrian Higgins
Thursday, August 7, 2008; H01

The honeybees seem to be bucking the trend and 
thriving for the moment, at least in my garden. 
So I have stopped watching them at work and 
turned my attention to the native bees.

The honeybee came over from the Old World, but 
there are more than 3,500 species of indigenous 
bee, from the pesky carpenter bee, which buzzes 
you in April as it starts to tunnel into your 
woodwork, to the tiny sweat bee, which alights on 
your arm to take a sip of perspiration. If you 
look closely and it's the right species, you can 
see that it shimmers an iridescent green.

Of all the native bees, the bumblebee is the 
cuddliest. All right, you wouldn't want to hug 
one (it will sting if really threatened), but the 
bumblebee is quite content to let you watch it 
work, buzzing from flower to flower in search of pollen and nectar.

"There's something very iconic about bumblebees," 
said Mace Vaughan, conservation director of the 
Xerces Society for Invertebrate Conservation, 
based in Portland, Ore. "They're like little flying bears."

This made me doubly curious, so I looked for bees 
on my Russian sage the other day and found a 
bumblebee at work, with a dark gray abdomen, 
balls of orange pollen on the legs and a creamy 
mane of hair on the thorax, like the fur stoles 
that women used to wear for a night on the town.

I called Sheila Colla, a bumblebee expert at York 
University in Toronto, and described it to her. 
She said it was either the common eastern 
bumblebee or the two-spotted bumblebee. A quick 
Internet search confirmed it as the former. "And 
they're absolutely everywhere," she said. For now, that is.

Colla is at the forefront of some alarming 
bumblebee research. As a doctoral student, she 
has been tracking other formerly common species 
of bumblebee. Colla took field surveys of 
bumblebees between 2004 and 2006 in southern 
Ontario, comparing the results with data gathered 
in the early 1970s. She could find only 11 
species, down from 14, and of those 11, four were 
in decline. Colla also spent periods in 2005 and 
2006 looking for one of the missing species, the 
rusty-patched bumblebee. She traveled to 43 sites 
in Ontario, Quebec and 14 states, including 
Virginia, Pennsylvania and North Carolina. The 
sites were chosen because the species had been 
recorded at those locations in surveys going back 
a century or more. The result: One rusty-patched 
bumblebee was found in a park in Ontario in 2005, 
but none elsewhere. That was her last sighting of the insect.

What is most alarming to entomologists is that 
the rusty-patched bumblebee used to be one of the 
most common bumblebees in fields, farms and 
gardens from Ontario to Georgia. "It was the 
third or fourth most common species out of 14," she said.

Locally, the bee was last recorded in 2002, said 
Sam Droege, of the Patuxent Wildlife Research Center in Laurel.

In addition, a second formerly ubiquitous species 
is in rank decline, the yellow-banded bumblebee. 
"Surveying this summer, we have found [it] in 
some places, but it seems to have been pushed into boreal forests," Colla said.

The Xerces Society has placed the rusty-patched 
bumblebee, the yellow-banded bumblebee and two 
western species, the western bumblebee and 
Franklin's bumblebee, on its red list of 
most-threatened insects. Franklin's, confined to 
southern Oregon and northern California, has not 
been found since 2004 and might be extinct.

But other common species are also showing signs 
of decline, according to the society, including 
the American bumblebee and the yellow bumblebee.

As with colony collapse disorder in honeybees, 
the causes of bumblebee decline are not 
scientifically defined and might be a combination 
of factors. The honeybee disorder, sometimes 
called CCD, has galvanized the global scientific 
community, given the honeybee's importance to 
crop pollination. The Xerces Society is 
assembling the data of approximately 30 
scientists in North America to document the state 
of the bumblebee, which is also an important pollinator.

"You look at all their data and what we see is 
really discouraging," said Scott Hoffman Black, 
the society's executive director. "It's a picture 
of a really drastic decline toward extinction."

Black and Vaughan say they hope the public's 
growing awareness of the honeybee's plight will 
spill over to the bumblebee and other native bees that might be in trouble.

Vaughan said the decline of many bumblebee 
species has engendered a number of theories, 
including habitat loss and the commercial rearing 
of bumblebees for crop pollination. The vibration 
of bumblebee wings is so violent that it causes 
the pollen from one bloom to shake onto another. 
This "buzz pollination" is particularly effective 
in fertilizing tomatoes, cranberries and 
blueberries. Commercial breeders took species of 
American bumblebees to Europe to perfect breeding 
techniques and then brought them back to the 
United States. Researchers theorize that these 
bees caught a disease from European bumblebees 
and have spread it to wild populations via 
escapees from commercial greenhouses.

Meanwhile, Colla is studying the effects of a 
relatively new class of pesticides called 
neonicotinoids, which were introduced in the 
early 1990s. The pesticides have been linked to 
the vanishing honeybees. Colla, in lab tests on 
bumblebees, said that when given doses as low as 
12 parts per billion, "they can barely move." The 
chemical affects the development of the queen bee's ovaries, she said.

Can home gardeners help? Sort of. "We don't have 
a smoking gun yet," Vaughan said. "Because the 
declines are so widespread, it signifies to us 
there's some sort of disease" beyond the control 
of the homeowner. But the gardener can take steps to help the bumblebee.

By planting lots of flowers that the bumblebee 
likes, "you're strengthening the immune system, 
strengthening their ability to produce more 
young," he said. The society's Web site lists 
shrubs, perennials and herbs that the gardener 
can plant to feed bumblebees, including asters, 
joe pye weed, blueberries, sunflowers, sedums, 
borage, hyssop and marjoram. (At 
<http://www.xerces.org>http://www.xerces.org, go 
to "Xerces Publications," then "Fact Sheets About 
Native Pollinators," then "Plants for Native Bees in North America.")

The second thing is to minimize the use of 
pesticides, especially when bees are on the wing. 
It is also up to a homeowner to monitor spraying 
by a landscape maintenance company.

"Most people don't know the difference between a 
bumblebee or a honeybee," Black said, "but we are 
seeing, since CCD reared its head, more and more 
people interested in the subject."

But the plight of the bumblebee is still 
relatively unknown. "They are small animals; 
people don't think about it," he said. "People 
are thinking about high gas prices and the war in Iraq."


© 2008 The Washington Post Company




*************************
Scott Hoffman Black
Ecologist/Entomologist
Executive Director
The Xerces Society for Invertebrate Conservation
4828 SE Hawthorne
Portland, OR 97215
Direct line (503) 449-3792
sblack at xerces.org

The Xerces Society is an international, nonprofit 
organization that protects wildlife through the 
conservation of invertebrates and their habitat.

To join the Society, make a contribution, or read about our work,
please visit <http://www.xerces.org/>www.xerces.org.


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