Archive for the ‘High Elev specialists’ Category

Frigid bumble bee, Bombus frigidus

Monday, July 27th, 2020


Field ID tips

The Frigid bumble bee, Bombus frigidus is a very rarely encountered bumble bee species in Washington. That may be because it is rarely looked for by individuals who go into the high country. That trend seems to be changing. I expect we will be adding additional locations to the map above. It has recently been detected at Harts Pass, by Rich Hatfield.

Key field marks are:

  • the yellow scutum and scutellum,
  • T1 & T2 yellow
  • T3 black (no white hairs)
  • T4 & T5 red/orange
  • high elevation

Similar Species

The Frigid bumble bee, Bombus frigidus is often found in association with two other high alpine specialists: the Forest bumble bee, Bombus sylvicola and the High country bumble bee, Bombus kirbiellus. All three show red on the abdomen.

The Frigid bumble bee, Bombus frigidus is easily distinguished from the Forest bumble bee because the red on a frigidus is at the end of the abdomen while the red on a sylvicola is on T2 and T3.

It is more of a challenge to visually separate the High country bumble bee from the Frigid bumble bee. They both have T1 and T2 yellow. The High country bumble bee, B. kirbiellus has black on the front half of T3, and yellow on the rear portion of T3. T4 and T5 are orange. Visually, this puts a break (yellow) between the black and red segments. This is in contrast with the Frigid bumble bee where black and red meet directly with no yellow line of separation.

Fuzzy-horned bumble bee, B. mixtus, and Sitka bumble bee, B. sitkensis are other similar species. A couple of key differences between kirbiellus and mixtus/sitkensis include:

  • Cloudy scutum on mixtus amd sitkensis /yellow on kirbiellus
  • Range (elevation)-one might find B. mixtus and sitkensis pretty high but you will not find frigidus in the lowlands

High country bumble bee, Bombus kirbiellus/balteatus

Monday, July 27th, 2020

As part of our quest to document all the bumble bee species found in Washington state the team of folks behind this website, David Jennings, Lisa Robinson and Don Rolfs established a state record for the High country bumble bee, Bombus kirbiellus.

In the summer of 2018 David organized an expedition to one of Washington’s high alpine regions, Horseshoe Pass. While in the high country Don netted and collected a bumble bee. We could not easily confirm it’s identity in the field, so it was collected. That bee was subsequently mounted and identified by Lisa. She keyed it out to be Bombus kirbiellus, better known as the High country bumble bee. Until we made this find, there had been no verifiable evidence of this species in Washington state.

Lisa reached out to Rich Hatfield, of the Xerces Society and he helped get our suspicions confirmed by having her identification collaborated by Dr. Paul H Williams at the Natural History Museum, London UK, a worldwide expert on the species.

Teamwork for the win!

Last year (2019), based on our finding, Rich Hatfield visited the site and wrote up his findings here: https://www.xerces.org/blog/bombus-kirbiellus . That would have been a fun trip to be on!

And in reading his article I learned something very useful! The preferred food plant of kirbiellus. Red paintbrush is an easy flower to spot on the landscape!

Again, teamwork for the win!

Field ID tips

The High county bumble bee, Bombus kirbiellus, is as the name suggests a high elevation specialist. There are only a few places high enough with enough resources available for kirbiellus in Washington. The species is much more common in the high alpine country of Colorado up into Montana.

The scutum and scutellum are both yellow, with a black band between the wings. T1 and T2 are yellow, T3 is black with some white hairs in a line, T4 and T5 show orange or red.

Similar Species

The High country bumble bee may be found in association with two other high alpine specialists: Forest bumble bee, Bombus sylvicola and the Frigid bumble bee, Bombus frigidus. All three show red on the abdomen.

The High country bumble bee is easily distinguished from the Forest bumble bee because the red on a kirbiellus is at the end of the abdomen while the red on a sylvicola is on T2 and T3.

It is more of a challenge to visually separate the High country bumble bee from the Frigid bumble bee. They have T1 and T2 yellow. B. kirbiellus has black on the front half of T3, and some yellow on the rear portion of T3. T4 and T5 are orange. Visually, this puts a break (yellow) between the black and red segments. This is in contrast with the Frigid bumble bee where black and red meet directly with no yellow line of separation.

Fuzzy-horned bumble bee, B. mixtus, is another similar species. A couple of key differences between kirbiellus and mixtus include:

  • Cloudy anterior thorax (scutum) on mixtus/yellow on kirbiellus
  • No yellow break between black and red on lower abdomen (mixtus)

As can be seen below, the front of the thorax is yellow, not cloudy. T1 and T2 are yellow. There is a narrow yellow band breaking up the black/red interface on lower tergites.

Forest bumble bee, Bombus sylvicola

Sunday, July 19th, 2020

The Forest bumble bee, Bombus sylvicola is a high altitude specialist. Here in Washington it is only found in the lofty elevations in the Olympics and Cascades. In a study done for the National Park Service, Bombus sylvicola, occurred only at sites between 1,113 and 2,023 meters in both parks.

The Forest bumble bee, Bombus sylvicola may be found in association with one or two other high alpine specialists: Frigid bumble bee, Bombus frigidus and the High country bumble bee, Bombus kirbiellus. All three show red on the abdomen. The Forest bumble bee appears to be the most common of the three species here in Washington state.

A general characteristic across these high altitude specialists relative to bumbles from lower elevations is long hair length. For this species, this would be relative to the Hunt bumble bee, Bombus huntii.

Field ID tips

First, this is one species where range is a prime consideration. Unless you are pretty high in the mountains, don’t expect to encounter the Forest bumble bee. The Forest bumble bee has a yellow scutum and scutellum, and T2 & T3 are red.

Similar species

The Forest bumble bee is easily distinguished from the Frigid bumble bee and the High Country bumble bee because the red on a frigidus and a kirbiellus is at the end of their abdomen while the red on a sylvicola is on T2 and T3. The same logic holds true for separating the Forest bumble bee from the Fuzzy-horned bumble bee, B. mixtus and the Sitka bumble bee, B. sitkensis.

The Forest bumble bee, B. sylvicola, has a color pattern similar to the Hunt bumble bee, B. huntii. They both have T1 yellow, T2 and T3 orange, T4 yellow. Luckily these two species can easily be separated based on range. The Forest bumble bee is a high alpine specialist while the Hunt bumble is comfortable in hot dry sites like the Dry Falls State Park lake basin.

The scutum is yellow in sylvicola. This can help distinguish between sylvicola and melanopygus, the Black tail bumble bee. The Black tail bumble has a cloudy scutum (black hairs mixed in with the yellow).

The Red-belted bumble bee, B. rufocinctus, has the potential to be confused with the Forest bumble bee. The Red-belted bumble bee shows T2 with some yellow. The Forest bumble bee has T2 all red.

To date, I (DJ) have not captured any images of sylvicola in Washington. The quest continues…