Posts Tagged ‘fervidus’

Bumbles mainly Yellow

Friday, July 24th, 2020

The Yellow bumble bee, Bombus fervidus is the primary species in this group. Tergites (upper abdomen) segments T1 thru T5 are yellow.

Another species to mention is van Dyle Bumble, B. vandykei. It traditionally falls in the “no red, yes stripes” group, but when I encounter it in the field I am often struck with how much yellow it shows.

Yellow head bumble females, B. flavifrons often show striking bright yellow on T1 and T2.

The yellow form of the California bumble bee, Bombus californicus also shows a lot of yellow.

The Nevada bumble bee has golden yellow on its thorax and T1, T2 and T3.

Other yellow bumbles that are commonly seen on the westside are drones/males of the Yellow head bumble bee B. flavifrons and the Fuzzy-horned bumble bee, B. mixtus.

Notice the rear (3rd) leg (above). Notice it is hairy and relatively round–no corbiculum. Big clue it is a male.

Males often have extra hairs on their upper lip (sound familiar?) giving them the appearance of have a mustache.

Yellow bumble bee, Bombus fervidus

Friday, July 17th, 2020

The Yellow bumble bee, Bombus fervidus, is, in Washington state, very much an east side species.

I have encountered it primarily in SE Washington, in and around the Blue Mountains.

Please reference the Embedded Range Maps page to better interpret
# of observations per ecoregion.

Field ID tips

Identification of the Yellow bumble bee, Bombus fervidus, is relatively straight-forward.

  • area between wings (alar) black
  • T1 = yellow
  • T2 = yellow
  • T3 = yellow
  • T4 = yellow
  • T5 = black
  • T6 = black

This is a sturdy bumble and easily noticed as it buzzes through the mountain wildflowers.

Similar Species

Two possible species that could cause confusion are the California bumble bee, B. californicus, and the White-shouldered bumble bee, Bombus appositus.

The yellow form of the California bumble bee will be very similar to the Yellow bumble bee, but shows some black on T2 and T3. There is disagreement about whether the California bumble bee is a subspecies of the Yellow. The two distinct forms come together in the Willamette Valley of Oregon, and you can see some of the mixed patterns that result.

White-shouldered bumble bee, B. appositus, will have distinctly different color shoulders (white) relative to the golden yellow of the abdomen.

The Nevada bumble bee, B. nevadensis shows a lot of yellow on it’s thorax and T1, T2 and T3. T4 and T5 will be black.

Males of several other species are yellow. See example below. Look for the lack of a corbiculum.