Bombus pensylvanicus

American Bumblebee
Bombus pensylvanicus


American Bumblebee Bombus pensylvanicus male
American Bumblebee Bombus pensylvanicus male on New England Aster. Sept 24, 2011. Wheatley, Ontario.
American Bumblebee Bombus pensylvanicus queen
American Bumblebee Bombus pensylvanicus queen on Purple Coneflower. July 15, 2006. Wheatley, Ontario.

Queen & Worker:
Head: Entirely black, sometimes with few gray hairs above base of the antenna.
Thorax: Base yellow to wing bases; last half mainly black; a few yellow mixed with black at end. Hair longer and thicker on worker.
Wings: Dark with black veins.
Legs: Black; fringe long, black.
Abdomen: Segments 1 to 3 are yellow. 4 to 6 are black.

Head: Face and cheeks have grey-white hairs with some black hairs intermixed. Top of head has black hair. Face not as black-looking as the Yellow Bumblebee B. fervidus.
Thorax: Yellow with black stripe between wing bases. Black stripe can extend to thorax end, but always with some yellow.
Wings: Dark
Legs: Black. Fringe on underside of thighs (femur) pale yellowish. Also pale yellowish pile on underside of hind shins (tibiae).
Abdomen: Abdominal segments 1 to 4 have dense, yellow, long drooping hairs. 5 can be yellow or black. 6 and 7 mostly black with yellow on the sides of the segments. Yellow hair at centre of abdomen tip.

Similar Species: Males are difficult to separate from The Yellow Bumblebee B. fervidus. B. fervidus has last 2 abdominal segments entirely black.

Size: Queen 22 to 25.5 mm. Worker 14 to 19 mm. Male 18 to 21.5 mm.

Flight Time: June through the end of September.

Habitat: Meadows, weedy fields, open areas, gardens.

Food: Generalist pollen and nectar feeders using a wide variety of flowers.

Life Cycle: Nests under a heavy mat of grass. Hibernating queens appear in spring and establish nests at ground level in grass tussocks, often on south-facing slopes. Sometimes on or beneath the surface of the ground. Also recorded nesting in an abandoned squirrel nest. She builds a wax honey pot and fills it with honey and pollen, then lays a batch of eggs on the pollen, covering them with a waxed sheet. Eggs are incubated by the female by warming her body temperature and laying on top of the eggs. Hatched larvae (up to 40) are continually fed by the queen. The first brood become workers and take over nest maintenance and honey & pollen foraging. Males help incubate pupa in the nest. The old Queen, workers and males die by the end of the season. Only mated females live to hibernate in sheltered locations until the next spring. Life span, except for mated females is 14 to 25 weeks.

Comments: Essex County – Ojibway Prairies. The American Bumblebee is a southern species at the northern limits of its range in south-west Ontario.