[Pollinator] Burlington Free Press: In Nature: The plight of the native bumblebee

[Jennifer Tsang]

http://www.burlingtonfreepress.com/apps/pbcs.dll/article?AID=/20070810/LIVIN
G/708100302/1004

 






In Nature: The plight of the native bumblebee

August 10, 2007
Madeline Bodin
Special to the Free Press

In the wooden storage boxes of the University of Vermont's insect
collection, there are plenty of examples of a native bumblebee species
(Bombus affinis) that has a black head, broad yellow stripes, and no common
name. Generations of net-wielding undergrads added fresh specimens to the
university's collection up until the 1990s. 

Since 1999, however, and in spite of searching across fields and through
forests, Leif Richardson, a Vermont-based bumblebee researcher, hasn't seen
a single member of that species. He knows of four other once-common Vermont
bumblebee species that have all but disappeared from the state as well. 

Bumblebees and honeybees have experienced sharp declines recently. News
reports of late have focused on Colony Collapse Disorder (CCD), a mysterious
syndrome that has killed off as many as 90 percent of the honeybees in some
beekeepers' hives in 35 states, including New Hampshire but not Vermont. 

But honeybees were in trouble long before CCD struck, and so were native
bees, including many bumblebee species, for a variety of reasons.

Just to be clear, honeybees are not native to North America. They are,
however, what most likely comes to mind when someone says "bee." There is
just one species that answers to the name honeybee in North America: They
live in large hives and produce honey; these days most honeybees are raised
primarily to pollinate crops. 

There are about 4,000 species of native bees in North America, says Stephen
Buchmann, international coordinator for the North American Pollinator
Protection Campaign and co-author of the book, The Forgotten Pollinators. 

Of those native bee species, bumblebees are perhaps the most like honeybees,
which may be one reason why the two are sometimes confused. Most bumblebees
are bigger than honeybees, and fatter. Both kinds of bees are fuzzy and
buzzy. 

But bumblebees nest in small colonies in the ground, often in abandoned
mouse or vole holes. They make some honey -- just enough for a rainy day --
but do not need a large surplus because their colonies don't overwinter as
honeybees' do. 

Richardson, whose day job is as the state lands ecologist at the Vermont
Fish and Wildlife's Nongame and Natural Heritage Program, says there are
about 20 species of bumblebees in Vermont. According to the University of
New Hampshire insect collection's checklist, there are 16 species in New
Hampshire. 

Bombus fervidus -- another bumblebee species (so few have common names) --
is also common in the UVM collection, says Richardson. New specimens stopped
being added to the collection in the 1990s. "I've looked hard for it, and
have rarely seen it," he says. He has spoken to researchers in the Midwest,
who have had little luck finding it. 

Bumblebees are not disappearing from just Vermont and New Hampshire. It's a
continent-wide phenomenon. Franklin's bumblebee, rare for having a common
name as well as for existing only in a small area in northern California and
southern Oregon, is believed to have recently gone extinct. It's one of five
bumblebee species, including B. affinis, that the Xerces Society for
Invertebrate Conservation has singled out for having a population in steep
decline. 

No one knows what is happening to bumblebees, but most experts are convinced
that loss of habitat, use of pesticides, and the introduction of non-native
parasites are playing important roles in the decline. 

Habitat loss can be extreme, such as when a pasture becomes a shopping
center, or it can be subtle. Richardson says Bombus pensylvanicus requires
large grasslands as habitat, and it nests in New Hampshire and Vermont on
the ground in hayfields. It was once common, he says, but he's seen the
species only once. He suspects that intensifying agriculture -- dairy
farmers now cut hay from a single field as often as three times a year --
has led to its decline. 

In some instances, bumblebees are employed to pollinate greenhouse tomatoes,
since honeybees are incapable of that job. As these bumblebees are
commercially raised and sold around the world, they pick up parasites, such
as mites, that can weaken or kill them. When infected bumblebees escape to
the wild, they bring those parasites to native populations. 

The good news is that scientists like Richardson are studying the problem at
the local level, giving policy-makers the information that they badly need.
The situation is starting to receive some national attention as well, says
Matthew Shepherd, pollinator conservation program director for the Xerces
Society in Portland, Ore. Last autumn, the National Academies of Science
released a report describing the dire state of pollinators in the United
States, including bumblebees. The report concluded that more research is
needed. Congress is now discussing funding for that research, says Shepherd.


The U.S. Postal Service celebrated National Pollinator Week on June 24-30 by
releasing a block of stamps depicting native pollinators and wild flowers.
One of the four stamps shows the flower of a purple nightshade being
pollinated by a bumblebee.
Madeline Bodin is a writer who lives in Andover. This weekly column is
produced by Northern Woodlands magazine. A selection of these columns has
been collected in The Outside Story, available at www.northernwoodlands.org.
Support for this article series is provided by the New Hampshire Charitable
Foundation's Wellborn Ecology Fund: wef at nhcf.org. 




Jennifer Tsang
Coevolution Institute <http://coevolution.org> 
423 Washington St. 5th Fl.
San Francisco, CA 94111-2339
T: 415.362.1137

F: 415.362.3070

www.nappc.org

www.pollinator.org

 

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