Goodbye, Franklin's Bumble Bee?

May 21, 2009

Let's have a show of hands.

How many of you have seen Franklin's bumble bee in the wild?

Never HEARD of it, you say?

Well, you probably will never SEE it, either. Bumble bee experts think it may be extinct.

Franklin's bumble bee is native to southern Oregon and northern California, but in recent years, it's been a "no show."

"Franklin's bumble bee has the most restricted distribution range of any bumble bee in North America, and possibly the world," said UC Davis researcher Robbin Thorp,  a noted authority on bumble bees.  Its range is about 190 miles north to south and 70 miles east to west in a narrow stretch between southern Oregon and northern California, between the coast and the Sierra-Cascade ranges.

Its known distribution: Jackson, Douglas and Josephine counties in Oregon, and Siskiyou and Trinity counties in California. It lives at elevations ranging from 540 feet in the north to 6800 feet in the south.

Thorp launched his scientific surveys for Franklin's bumble bee in 1998. He documented about 100 of them that year. They were, he said, fairly common.

Since 2004, however, he's seen the unique bumble bee only once. And that was a solitary worker in August 2006 at Mt. Ashland, Ore.

The black-faced bumble bee (Bombus franklini)  is distinguished by a black inverted U-shape on its yellow thorax.  See Thorp's photo below. Note also the yellow markings atop its head.

Franklin's bumble bee frequents (or shall we say, "used to"  frequent) California poppies, lupines, vetch, wild roses, blackberries, clover, sweet peas, horsemint and mountain penny royal during its flight season, from mid-May through September. It collects (or shall we say "used to" collect) pollen primarily from lupines and poppes and gathers nectar mainly from mints.

Thorp just returned from the region in mid-May and found nothing. He journeys to the region three to five times a year, spending several days looking for the bumble bee on each trip. 

It's not there.

Thorp is concerned, as we all should be, that humankind is disturbing, destroying and altering the habitat where the native pollinators exist.

He'll be speaking on the plight of the bumble bee from 12:10 to 1 p.m., Wednesday, May 27 at 122 Briggs Hall, UC Davis. His talk will be Webcast. You can view it by signing in here at that time. Later, it will be archived on this page.

Bumble bees, Thorp said, are important to our ecosystem. Wildlife, including birds, elk, deer and bears, depend on pollination of fruits, nuts and berries for their survival.

Other species of bumble bees are commercially reared to pollinate greenhouse tomatoes, peppers and strawberries. They  pollinate about 15 percent of our food crops, valued at $3 billion, Thorp estimated.

Goodbye, Franklin's Bumble Bee? Hello, distinction?

By Kathy Keatley Garvey
Author - Communications specialist

Attached Images:

UC DAVIS RESEARCHER Robbin Thorp with a computer screen showing Franklin's bumble bee. He captured this image on a California poppy. (Photo by Kathy Keatley Garvey)

Robbin Thorp

THIS CLOSE-UP of Franklin's bumble bee, taken by UC Davis researcher Robbin Thorp, shows the distinctive black-inverted U-shaped design on its yellow thorax. Thorp fears that Franklin's bumble bee, found only in southern Oregon and northern California, may be extinct.