Bombus franklini (Frison 1921)

Franklin's bumble bee (Bombus franklini) is a generalist forager and is known to nectar and collect pollen from several wildflowers, such as lupine (Lupinus spp.), California poppy (Eschscholzia californica), horsemint (Agastache urticofolia), mountain penny-royal (Monardella odoratissima), and vetch (Vicia spp.). The Franklin's bumble bee can be distinguished from other bumble bees by its distinctive pattern of yellow on the thorax that extends rearward forming an inverted U-shape. It has an almost completely black abdomen with two small white spots at the tip. Females have a predominantly black face with yellow on top of the head, while males have mostly yellow on the front of their faces. The Franklin's bumble bee has the smallest range of any bumble bee in the world, occurring between southern Oregon and northern California between the Coast and Sierra Cascade Ranges. It's range encompasses 190 miles north to south and 70 miles east to west. In the past the Franklin's bumble bee was abundant in its range, but is now feared to be extinct or nearly so. Surveys throughout the bee's range were unable to locate any individuals in 2004, 2005, and 2007; one worker bee was found in 2006. Franklin's bumble bee underwent extreme declines in the late 1990's, most likely because of exotic diseases that were inadvertently introduced through commercial bumble bee importations for greenhouse pollination of tomatoes. Other threats include habitat loss, pesticides, and pollution.

In 2012, Bombus franklini was included among the world's 100 most threatened species in a report by the IUCN Species Survival Commission and the Zoological Society of London.

(Baillie & Butcher 2012; Harvey 2012)

Franklin's bumble bee is a generalist forager and is known to nectar and collect pollen from several wildflowers, such as lupine (Lupinus spp.), California poppy (Eschscholzia californica), horsemint (Agastache urticofolia), mountain penny-royal (Monardella odoratissima), and vetch (Vicia spp.).