Posts Tagged: Bombus occidentalis
Incredible. Absolutely incredible.
The Western bumble bee (Bombus occidentalis) seems to be making a comeback of sorts in some parts of the West.
Reporter Michelle Nijhuis, in an Oct. 14th article in High Country News, wrote that this species was "once among the most common bumble bees in the Western United States (and Western Canada)." The population crashed in the 1990s and "all but disappeared from about a quarter of its historic range." Now, she says, it's recently been spotted in parts of Washington and Oregon.
Someone saw six species of the Western bumble bee pollinating blackberries just north of a Seattle.
That's good news indeed.
We remember last year when native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, was searching for the critically imperiled Franklin's bumble bee in its tiny range in northern California and southern Oregon, when a sole Western bumble bee appeared in front of him and his colleagues from the U.S. Forest Service. It was foraging on buckwheat (Eriogonum sp.) on Mt. Shasta, above 5000 feet.
Thorp and many other scientists fear that the Western bumble bee may go the way of Franklin's bumble bee.
That's why Thorp describes the Seattle find as "very exciting."
"Any finds west of the Sierra-Cascade crest are of prime interest. It is those western populations that took the sharp dive between 1999-2002. They do seem to be increasing, which is indeed encouraging."
"Many populations east of the crest seem to have persisted, through this decline," Thorp noted, "but were not carefully monitored during this time so we don't have the detailed data on their population trends that we would like."
Bombus occidentalis is sometimes called the "white-bottomed bee" due to its distinctive white markings on its abdomen. It is known for pollinating blackberries, cherries, apples and blueberries. It also is "an excellent pollinator of greenhouse tomatoes and cranberries, and has been commercially reared to pollinate these crops," according to the Xerces Society for Invertebrate Conservation website.
Read about the decline of bumble bees on the Xerces website.
And if you live in the West, keep your eyes open for the Western bumble bee.
This Western bumble bee was found on Mt. Shasta on Aug. 15, 2012. (Photo by Kathy Keatley Garvey)
Close-up of Western bumble bee. (Photo by Kathy Keatley Garvey)
Many of us in California have never seen the Western bumble bee (Bombus occidentalis)
Many of us never will.
Native pollinator specialist Robbin Thorp, emeritus professor of entomology at the University of California, Davis, worries about the declining population and fears it may go the way of Franklin's bumble bee, which he hasn't seen since 2006.
That's why he and his colleagues were so excited to find a male Bombus occidentalis on Mt. Shasta, above 5,000 feet, on Aug. 15. It was foraging on buckwheat (Eriogonum sp.).
Thorp was there with several local U.S. Forest Service employees: wildlife biologist Debbie Derby, who actually netted the bee; and biological technicians Susan Thomas, Kendra Bainbridge and Lauran Yerkes.
"Just as we were celebrating the find, we were joined by two other USFS personnel: Carolyn Napper, district ranger, and Johnny Dame, Panther Campground host," Thorp recalled. "So there were lots of witnesses to the rare find."
A rare find, indeed.
The Western bumble bee, a close relative of Franklin's bumble bee (Bombus franklini), "disappeared from the western part of its range at the same time as Franklin's bumble bee declined," said Thorp, who keeps an eye out for both species on his trips to southern Oregon and northern California.
The habitat of the Franklin's bumble bee, which many fear is extinct, is a 13,300-square-mile area of Siskiyou and Trinity counties in California, and Jackson, Douglas and Josephine counties in Oregon.
"The Western bumble bee occurred throughout the range of Franklin’s, but apparently declined from central California to southern British Columbia west of the Sierra Cascade Range at the same time as the decline of Franklin's bumble bee, " Thorp said.
However, the Western bumble bee "seems to have persisted through most of the rest of its range from Alaska through areas east of the Sierra-Cascade to the Rocky Mountains and south to Arizona and New Mexico," Thorp pointed out. "We have no good idea what the population trends have been within this large area, since no one has been closely monitoring its populations there."
We're glad to see the increased interest in bumble bees. And especially glad to see that this week the Xerces Society for Invertebrate Conservation announced the publication of Bumble Bees of the Western United States, co-authored by Jonathan Koch, James Strange and Paul Williams. You can order it online.
Bombus occidentalis and Bombus franklini are among the Bombus species represented.
Close-up of a male Western bumble bee (Bombus occidentalis) found Aug. 15 at Mt. Shasta. (Photo by Kathy Keatley Garvey)
Another view of the male Western bumble bee found on Mt. Shasta. (Photo by Kathy Keatley Garvey)
Documenting the rare find. (Photo by Kathy Keatley Garvey)
Native pollinator specialist Robbin Thorp is a retired UC Davis professor, but continues his full-time research. (Photo by Kathy Keatley Garvey)