Bombus auricomus

Black and Gold Bumblebee
Bombus auricomus

Black & Gold Bumblebee Bombus auricomus queen
Black & Gold Bumblebee Bombus auricomus queen on Obedient Plant or False Dragonhead, Sep 02, 2012 Wheatley, Ontario.
Black & Gold Bumblebee Bombus auricomus worker
Black & Gold Bumblebee Bombus auricomus worker on Everlasting Pea Jul 08, 2013 Wheatley, Ontario.
Black & Gold Bumblebee Bombus auricomus queen
Black & Gold Bumblebee Bombus auricomus queen on Obedient Plant or False Dragonhead, Sep 02, 2012 Wheatley, Ontario.
Black & Gold Bumblebee Bombus auricomus worker
Black & Gold Bumblebee Bombus auricomus worker on Hyssop Aug 21, 2012 Wheatley, Ontario.
Black & Gold Bumblebee Bombus auricomus worker
Black & Gold Bumblebee Bombus auricomus worker on pants Jul 21, 2006 Wheatley, Ontario.
Black & Gold Bumblebee Bombus auricomus worker
Black & Gold Bumblebee Bombus auricomus worker on Everlasting Pea Jul 08, 2009 Wheatley, Ontario.

Identification: The female has abdominal segments 2 and 3 yellow. Segment 1 is black but usually has yellow at side edges. The male has segments 1 to 3 yellow.
Queen and Worker:
Head: Face entirely black with a band of yellow hairs across back of head.
Thorax: Base of thorax yellow; a wide black stripe between wing knobs with the lower border forming a V-shape at centre. Lower thorax has yellow erect hairs on each side of black V-shape.
Wings: Wing knobs reddish-black. Wings black, a bit lighter at tips.
Legs: Legs and hair entirely black.
Abdomen: Abdomen segment 1 narrow, black; some yellow at side edges. Segments 2 and 3 are yellow; remainder of segments black. Segment 2 is wide.

Male:
Head: Face has short, yellow hair with some black in centre of face. Top of head has short yellowish hairs. Eyes are large.
Thorax: Base of thorax yellow; a wide black stripe between wing knobs with the lower border forming a V-shape at centre. Lower thorax has yellow erect hairs on each side of black V-shape.
Wings: Wing knobs reddish-black. Wings are uniformly dark, but not as dark as the female.
Legs: Hair gray to blackish. Tops of legs with very fine, pale grayish hairs. Note: Males do not have the characteristic bright yellow fringe on underside of thighs (femora).
Abdomen: Segments 1 to 3 entirely yellow with a slight reddish tint. Segments 4 to 7 black, the hairs longer and erect.

Similar Species: American Bumblebee Bombus pensylvanicus female resembles the male B. auricomus but has very little yellow fringe on lower thorax or on head. Worn workers with lower thorax yellow hairs missing can easily be mistaken for B. pensylvanicus, and best ID’d by abdominal stripes – B. pensylvanicus has segments 1 to 3 yellow.

Size: Queen 20 to 25 mm.Worker 18 to 20 mm – large for worker. Male 17 to 20 mm.

Flight Time: Late June to early September.

Habitat: Meadows, forest edges.

Food: Pollen & nectar from a wide variety of flowers.

Life Cycle: Hibernating queens appear in spring and establish underground colonies in old mouse nests or other cavities. Queens lay their eggs in separate cells. Hatched larvae are continually fed by the queen until they pupate. After this group of workers emerge as adults, they take over feeding the larvae. Nests usually have between 30 to 50 workers. Only mated females over-winter, hibernating in sheltered locations until the next spring.

Comments: Essex County – Ojibway Prairies, Point Pelee and Pelee Island. The Black and Gold Bumblebee Bombus auricomus is a southern bumblebee, at the northern limits of its range in Ontario.

Leave a Reply