Prepared by: Robbin W. Thorp, University of California, Davis
Citation: Thorp, R. W. 2005. Species Profile: Bombus franklini. In Shepherd, M. D., D. M. Vaughan, and S. H. Black (Eds). Red List of Pollinator Insects of North America. CD-ROM Version 1 (May 2005). Portland, OR: The Xerces Society for Invertebrate Conservation.
Xerces Red List Status: Critically Imperiled (Possibly Extinct)
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. However, there has been a precipitous decline in numbers and localities of occurrence since 1998. No Franklin’s Bumble Bee were observed during surveys in 2004. Threats include: 1) Exotic diseases introduced via trafficking in commercial bumble bee queens and colonies for greenhouse pollination of tomatoes; 2) Habitat loss due to destruction, degradation, conversion; and 3) Pesticides and pollution.