Archive for the ‘Red middle abdomen’ Category

Vancouver bumble bee, Bombus vancouverensis

Wednesday, July 29th, 2020

Stop the presses! As of July 29, 2020 Washington state has a new bumble bee species. Genetic analysis has determined that the population of the Two form bumble bee, Bombus bifarius in British Columbia has been recognized as a new, separate species. This new species is the Vancouver bumble bee, Bombus vancouverensis. This includes the population located in the San Juan Islands. Ergo, we have a new species!

What is not clear is what the actual differences are between the Vancouver bumble bee and the Two form bumble bee. At first I (DJ) thought that the individuals showing red on T2 and T3 were vancouverensis and the ones with T2 and T3 black were bifarius. Now it appears separating the two species in Washington may be a bit more challenging. It appears that the two color morphs are subspecies of the same species (B. vancouverensis)

As I am interpreting (please correct me if you know better!) the colorful color morph found in the San Juans Islands is the Vancouver bumble bee subspecies Bombus vancouverensis vancouverensis, while the form that we knew in the eastern part of Washington as the Two Form Bumble bee (Bombus bifarius) is now the Vancouver bumble bee subspecies Bombus vancouverensis nearcticus. For more discussion on this taxonomic question, please refer to the Two Form bumble bee page.

For a more complete discussion on field identification of the Bombus vancouverensis nearcticus subspecies refer to the Two Form bumble bee page.

Field ID Tips

Range, range, range. As far as I am currently aware, within Washington state, the Vancouver bumble bee Bombus vancouverensis vancouverensis subspecies is restricted to the area around the San Juan Islands. It has a similar color pattern to the Two Form bumble bee. It shows an inverted black triangle on the scutellum. T1 & T4 are yellow. T2 and T3 show a lot of red. T2 may show a black notch.

Similar Species

The red morph of the Yellow head bumble bee, which is also located in the San Juans, is somewhat similar, but it show red on T3 and T4. The Yellow head bumble bee also lacks an inverted black triangle.

The Black tail bumble bee shows red in the middle of the abdomen. T4 is black with a white line of hairs, no inverted black triangle.

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…

Hunt bumble bee, Bombus huntii

Saturday, July 18th, 2020

The Hunt bumble bee, Bombus huntii, is in my book one of the most spectacular bumbles we have in Washington. Their colors can be so brilliant. Once you encounter and identify this species, you will rarely have difficult identifying other such individuals.

Field ID tips

At the photographic detail level, the field marks that distinguish the Hunt bumble bee, B. huntii are

Again, once you encounter one I doubt you will find them confusing to separate from other species. Sometimes the colors are faded on a older individual (check wing condition for an estimate of age) so the patterns of color need to be noted.

Similar Species

The main species in Washington with a similar color pattern is the Forest bumble bee, Bombus sylvicola. Key differences between the two species are first: range. The Forest bumble bee is a high altitude specialist while the Hunt bumble is a lowland dry country specialist. Think Dry Falls State Park. The second key difference is on T5. The T5 on a female Hunt bumble bee is all black. The T5 on a Forest bumble will show yellow, possibly with a black notch.

Based on where the majority of the detections are in the map above, the Hunt bumble bee is very much a dry country / east side species.

T1 = yellow, T2, T3 = orange, T4 = yellow, T5 black. The abdominal segments are relatively easy to count off in these pictures.

Black tail bumble bee, Bombus melanopygus

Friday, July 17th, 2020

The Black tail bumble bee, Bombus melanopygus, can be encountered in many areas around Washington state: Lowlands like Tumwater on the west side, in the mountains and over across the top of the state and beyond.

When I first started taking pictures of bumbles this species was one of the first I submitted to Bumble Bee Watch. It was also the species that taught me the bumble bee term “cloudy“. Cloudy is the term to describe bumble patterns that have a mixture of black and yellow hairs. On the Black tail bumble bee, the area in front of the wings (scutum) and behind the head is such a mixture of black and yellow. And on the Black tail bumble that cloudiness is very obvious.

Field ID tips

Abdomen pattern is similar in many respects to the Hunt bumble bee, with the big difference at T4.

The Black tail bumble bee

  • Anterior thorax = cloudy (area in front of wings)
  • T1 = yellow
  • T2 = orange
  • T3 = orange
  • T4 = black with some white hairs
  • T5 = black

T4 is black with some white hairs rather than cloudy because the white hairs are in a distinctive line rather than mixed in among the black hairs.

Similar Species

Species that could cause confusion include:

My experience has been that the Black tail bumble bee is pretty distinctive most of the time, leading to confident field identification.

Central bumble bee, Bombus centralis

Friday, July 17th, 2020

Within Washington state, this species is most clearly an east side one. While there may be a sighting or two on the west side, over on the east side it can be relatively common.

This species clearly shows red on the abdomen. What makes it easy to separate from all others is that the red is on tergites T3 and T4.

  • T1= yellow
  • T2 = yellow
  • T3 = orange
  • T4 = orange
  • T5 = black

Within eastern Washington, there are few other species that one might confuse with the Central bumble bee. One possibility would be if you encountered a reddish form of Yellow head bumble bee, B. flavifrons.

The red forms of B. flavifrons have a cloudy front thorax. The Central bumble bee has a yellow one.

Red-belted bumble bee, Bombus rufocinctus

Friday, July 17th, 2020

The Red-belted bumble, Bombus rufocinctus, is the species of bumble in Washington state that show the greatest diversity of color patterns. If you check Bumble Bees of the Western United States, by Koch et al, you will see that not all red-belted bumbles even show red! This is one of my most challenging species to identify. Catching one to look at under a hand lens, to confirm cheek shape may be helpful.

To quote from that reference guide: “similar to many color patterns shown by both western and eastern NA bumble bees…small bodied, short-haired, short face.” emphasis added.

Field ID Tips

I think that maybe identifying Red-belted bumble bees may be easier than I have made it out to be. They have been the species “most mysterious” from a confident field ID perspective–since there is so much variability in their color patterns.

Having said that, T2 usually shows some level of yellow, and at least as I know so far, the color morphs in Washington are all of the “shows some red” group, rather than the forms where the red is black. So, T2 with yellow, some red on abdomen.

What else. Small bodied bee, hair length relatively short and even. Very short cheek–this is one time where being able to capture an individual, cool it briefly and example the cheek ratio can be very helpful for a confidential identification.

Similar species

The next element is process of elimination from other possible bumble bees. Within Washington, there are four possible bumble species that might cause confusion: the Black tail bumble bee, the Two form bumble bee, the Hunt bumble bee and the Forest bumble bee.

The Red-belted can be distinguished from the Black tail bumble bee, B. melanopygus because the Red-belted’s scutum is yellow, while the Black tail scutum is cloudy.

The Red-belted can be separated from the Two form bumble bee, B. bifarious, because the Red-belted lacks the black inverted triangle.

The Red-belted can be separated from the Hunt bumble bee, B. huntii and the Forest bumble bee, B. sylvicola because those two species have T2=Red

The Red-belted bumble is primarily found in eastern parts of Washington. The Blue mountains are a good place to look for them.