[Pollinator] IUCN lists Franklin’s Bumble Bee (Bombus franklini) as Critically Endangered

[Scott Black]

IUCN lists
Franklin's Bumble Bee (Bombus franklini) as Critically Endangered

The International Union for the Conservation of Nature (IUCN) has 
listed Franklin's bumble bee as a Critically Endangered species, 
based on surveys by Dr. Robbin Thorp that demonstrated that 
Franklin's bumble bee populations have decreased drastically over the 
past decade. Dr. Thorp has visited numerous sites that were once home 
to Franklin's bumble bee; while he found 94 individuals in 1998, he 
did not find any Franklin's bumble bees in 2004, 2005, or 2007, and 
only saw one individual in 2006.

Known only from southern Oregon and northern California between the 
Coast and Sierra-Cascade Ranges, Franklin's bumble bee has the most 
restricted range of any bumble bee in the world. Its entire 
distribution can be covered by an oval of about 190 miles north to 
south and 70 miles east to west.Threats to this species include: 1) 
Exotic diseases introduced via trafficking of commercial bumble bee 
queens and colonies for greenhouse pollination of tomatoes; 2) 
Habitat loss due to destruction, degradation, conversion; and 3) 
Pesticides and pollution.

Bumble bees are excellent crop pollinators and act as an insurance 
policy for farmers when honey bees are in short supply. In the U.S., 
the economic value of the pollination services provided by native 
insects (mostly bees) is estimated at $3 billion per year. In some 
crops, such as cranberries and blueberries, bumble bees pollinate 
more effectively than honey bees. Bumble bees are able to fly in 
cooler temperatures and lower light levels than many other bees, 
which makes them excellent crop pollinators. They also perform a 
behavior called "buzz pollination," in which the bee grabs the pollen 
producing structure of the flower in her jaws and vibrates her wing 
muscles. This causes vibrations that dislodge pollen from the flower. 
This behavior is highly beneficial for the cross-pollination of 
tomatoes, peppers, cranberries, and blueberries. In tomatoes, buzz 
pollination by bees results in larger and more abundant fruit. Losses 
of bumble bees can have far ranging ecological impacts due to their 
role as pollinators. In Britain and the Netherlands, where multiple 
bumble bee and other bee species have gone extinct, there is evidence 
of a decline in the abundance of insect pollinated plants.

Robbin Thorp (Professor Emeritus at the University of California, 
Davis), Peter Kevan (Associate Professor, Department of Environmental 
Biology, at the University of Guelph), and Xerces Society staff have 
collaborated to promote this species for IUCN consideration.

For more information on Franklin's bumble bee and other bumble bees 
in decline go to: http://www.xerces.org/bumblebees/, and for specific 
information on Franklin's bumble bee, please visit: 
http://www.xerces.org/bumblebees/franklini.html .

To see the IUCN listing go to: http://www.iucnredlist.org/details/135295



*************************
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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