Editor’s note: Our original banner photo featured a Nevada bumble bee foraging on periwinkle, a common garden plant that can have invasive habits. While periwinkle is not currently listed as a noxious or invasive plant in Alberta, we recommend finding native alternatives, like those found in our prairie urban garden booklet. As there is a shortage of native flowers, pollinators are forced to use non-native species—a great reminder to plant more native flowers in our gardens.

Jessenia Buzunis-Delagneau is a recent graduate of the University of Lethbridge who spent the last year of her degree working on an Honour’s Thesis project on the bumble bees of Lethbridge. This blog contains excerpts from Jessenia’s “Bumble Bees of Lethbridge, Alberta” guide, which summarizes her thesis project. The full guide (linked below) contains a more comprehensive introduction to bumble bees, her project methodology, and advice on the specifics of observing and photographing bumble bees. In this blog, we look at 3 bumble bees commonly found in Lethbridge gardens and parks, as well as 4 bumble bee species at risk found in Southern Alberta.

The photos contained in the blog are from Jessenia's report, unless otherwise noted, and were taken in parks and gardens throughout Lethbridge. As such, they may contain non-native plants.

As part of my undergraduate thesis, I spent the summer of 2024 identifying and documenting the different species of bumble bees present in Lethbridge. In this work, I have shared what I have learned about the species present, their relative abundances, floral associations, and tips on how to identify the 12 different bumble bee species I observed in Lethbridge. Whether you care for bumble bees out of a simple love for them, a desire to know the little gardeners who help plants make your produce, or a wish to contribute to citizen science and perhaps aid in bumble bee conservation, I hope that this blog and report will be useful to you in better understanding our little Lethbridge local bumble bees.

Introduction to Bombus

While they are not the only type of native bee present in Lethbridge, bumble bees (bees in the genus Bombus) may be the most well known, and perhaps the most beloved. The name Bombus comes from the Latin word for “booming”, “buzzing” or “humming” referring to the loud buzzing sound they produce while they fly (Merriam-Webster, n.d.). Many of us have come to know and love this familiar sound as the herald of an approaching bumble bee in our gardens or a field of flowers on a warm spring or summer day. Certainly, those who are fond of creatures with almost kitten-like fluff, beautiful bright colours, and the heartwarming mutualism of plant-pollinator interactions should find themselves to be fans of bumble bees.

Beyond physical appeal, bumble bees also provide plants and animals, including humans, with important pollination services. Bumble bees are one type of bee capable of “buzz pollination”, a unique type of pollination in which the bee buzzes at a particular frequency which stimulates the flower to release pollen (Cooley & Vallejo-Marín, 2021). This process is either required or greatly beneficial to the pollination of many plant species, including many crops (Cooley & Vallejo-Marín, 2021). Enjoyers of tomatoes, blueberries, eggplants, and more should all be thankful to bumble bees for their valuable role in production (Cooley & Vallejo-Marín, 2021).

This report should not serve as a definitive guide for bumble bee identification; however, it will serve as a good introduction to the bumble bees in the Lethbridge region. This guide will focus primarily on morphological traits and colouration, which are easily seen in photos and in living specimens but are not the best for definitive identification.

Particularly with male bumble bees, identification based on colouration can be particularly difficult, and often requires the identifier to capture and kill the bee. Those looking to identify Lethbridge bumble bees with more certainty and/or for research purposes may need to destructively sample specimens to view microscopic characteristics or look at male genitalia and should refer to other more detailed guides such as Williams et al.’s Bumble Bees of North America (2014). Additionally, Bumble Bees of Calgary (Neame et al., 2023) served as another very useful guide for my work and while writing this report. Bumble Bees of Calgary also focuses on coloration patterns, and only addresses the identification of females, but is regardless a very useful and user-friendly guide to refer to where this guide is insufficient.

Bumble Bee Anatomy

To identify a bumble bee, it is important to understand the terms used when describing bumble bee ID traits. Figure 1 shows a diagram of a bumble bee focusing on the terms and structures referenced in this guide.

***Figure 1***. General anatomy of a female, non-cuckoo bumble bee. Females of the subgenus Psithyrus (cuckoo bumble bees) and all males differ in that they lack a corbicula (pollen-carrying structure). Male bumble bees differ in that they have an 7th tergite (abdominal segment), giving their abdomen in general a longer and often pointier appearance. Males also have an additional segment to their antennae, which in some species gives the appearance of longer antennae. Tergites are abbreviated as T1-7 in the guide. Image credit: Jessenia Buzunis-Delagneau.

Common Bumble Bees in Lethbridge

Hunt’s Bumble Bee

Bombus huntii

B. huntii was the most common bumble bee species in Lethbridge in 2024 and represented 222 of the 364 observed bumble bee floral interactions.

Two photos of Bombus huntii. Note the pattern of yellow, orange, yellow, black on the abdomen, and the yellow hairs on the head and face.

For workers and queens, T1 is yellow, T2 and 3 are orange, T4 is yellow, and T5 and 6 are black. The thorax is yellow with a black inter-alar band in the inter-alar space, and the head and face are yellow (Neame et al., 2023; Williams et al., 2014). This species can be distinguished from the similar species, Bombus ternarius by the coloration of the face, head, and inter-alar space (Neame et al., 2023; Williams et al., 2014). The face and head of B. huntii is yellow, while the face of B. ternarius is blacker, although the face of B. ternarius sometimes has some yellow hairs. A more concrete way to differentiate the two is by the inter-alar band. The band in B. ternarius extends posteriorly, almost or completely bisecting the scutellum, while the inter-alar band of B. huntii does not (Neame et al., 2023; Williams et al., 2014). Additionally, B. huntii was far more common in Lethbridge in 2024 than B. ternarius. [See full guide for profile and photos of B. ternarius].

B. huntii males are similar in appearance to females; T1 is yellow, T2 and 3 are orange, T4, 5, and 6 are yellow, and T6 and 7 are black; and the face and head are yellow (Williams et al., 2014). The thorax is yellow with a black band across the inter-alar space, although for males of B. huntii there are sometimes yellow hairs intermixed into this band (Williams et al., 2014).

Great Basin Bumble Bee

Bombus centralis

B. centralis was the second most common bumble bee in Lethbridge in 2024 and represented 71 of the 364 observed bumble bee floral interactions.

For queens and workers T1 and T2 are mostly yellow, often with some black in the centre, T3 and T4 are orange, and T5 and T6 are black (Neame et al., 2023; Williams et al., 2014). There is a black band in the inter-alar space, and the face and head are mostly yellow (Neame et al., 2023; Williams et al., 2014). Males of this species are similar in appearance to females (Williams et al., 2014). Of those B. centralis males I observed in 2024, T1 and T2 were yellow, often with some black in the center, T3, T4, and T5 were orange, often with a yellow line along the lateral edge, and T6 and T7 were black.

Any difficulty associated with identifying this species in Lethbridge (once one is clear on the differences between the abdomen of this species and B. huntii) is likely to come from confusion with B. rufocinctus, which has a color morph very similar to the coloration of B. centralis. However, B. centralis has a longer cheek than B. rufocinctus (Neame et al., 2023; Williams et al., 2014), and additionally B. centralis often has a yellow line along the lateral edge of the orange tergites […], which B. rufocinctus does not (Joel Neylon, personal communication, June 8, 2024). [See full guide for profile and photos of B. rufocinctus]

Nevada Bumble Bee

Bombus nevadensis

B. nevadensis was relatively common in Lethbridge in 2024 and represented 14 of the 364 observed bumble bee floral interactions.

I find that this species is the most easily identified among the species found in Lethbridge. B. nevadensis is the largest species in Lethbridge, and a keen ear may be able to identify queens by sound alone, as they produce a loud and distinctive booming buzz when they fly. A bee truly worthy of the name Bombus. Additionally, bees of this species have a short and even coat (Williams et al., 2014), giving them a distinctive almost velvet-like appearance, rather than the fluffier appearance of the other Lethbridge bumble bees.

Queens and workers of this species usually have a round black dot on the dorsal side of their thorax in the inter-alar space, although sometimes this is replaced by a black stripe (Neame et al., 2023; Williams et al., 2014). T1, T2 and T3 are yellow, and T4, T5, and T6 are black (Neame et al., 2023; Williams et al., 2014). The face and head are usually black, and the wings have a dark tint (Neame et al., 2023; Williams et al., 2014).

B. nevadensis males are distinctive and rather dissimilar in appearance to females (Williams et al., 2014). B. nevadensis males have very large eyes and short antennae (Neame et al., 2023; Williams et al., 2014). The only other bumble bee in Lethbridge which similarly large eyes is the very uncommon male B. griseocollis, which has longer antennae, and can also be distinguished from B. nevadensis based on coat color. B. nevadensis males have a coat colour pattern similar to queens and workers, although T6 and T7 are typically orange (Williams et al., 2014).

Bumble Bee Species at Risk Found in Lethbridge

Yellow Bumble Bee

Bombus fervidus

Listed as vulnerable by the IUCN (Hatfield et al., 2015). B. fervidus was relatively common in Lethbridge in 2024 and made up 18 of the 364 observed bumble bee floral interactions.

Queens, workers, and males of this species are similar in appearance in that the head and face are black, there is usually a black band in the inter-alar space, the most posterior tergite is black, and everything else is yellow ((Neame et al., 2023; Williams et al., 2014). This species can be distinguished from the similar species Bombus borealis by the black head and face, as the head and face of B. borealis are yellow (Neame et al., 2023; Williams et al., 2014). The cheek of this bee is quite long (Williams et al., 2014), and therefore difficult to confuse with B. rufocinctus when one is able to get a good look at or photo of the face.

Western Bumble Bee

Bombus occidentalis

Listed as Threatened by COSEWIC (COSEWIC, 2014). B. occidentalis was relatively common in Lethbridge in 2024 and made up 14 of the 364 observed bumble bee floral interactions.

B. occidentalis has a short cheek, giving it the appearance of a small, squished face. However, B. occidentalis always has a distinct white (or at least, pale yellow) patch on the posterior-most tergites (Williams et al., 2014) that make it stand out amongst other bumble bees on the landscape. Queens and workers have a black head and face, although there may be some light hairs intermixed, and males may occasionally have a yellow face (Williams et al., 2014). For all members of this species, T1 is black, T2 is usually black, although it may be yellow in males and workers, T3 may be black or yellow or a combination, and T4 may be black, yellow, white, or a combination (Williams et al., 2014). In queens, T5 is always at least partially white, while it may be white or black in workers, and is generally at least partially white or pale yellow in males and T6 and T7 are always white or pale yellow (Williams et al., 2014).

For males and females, the scutum is always yellow (Neame et al., 2023; Williams et al., 2014). The inter-alar space is at least partially black, and typically the lateral edge of the thorax under the base of the wings is black (Neame et al., 2023; Williams et al., 2014). The scutellum may be black or yellow (Williams et al., 2014), although for all B. occidentalis that I observed, it was always mostly yellow.

At-Risk Bumblebees to Look Out For

The following species were not observed in Lethbridge in 2024, but readers should keep an eye out for:

Suckley’s Cuckoo Bumble Bee

Bombus suckleyi

To my knowledge, B. suckleyi was not recorded in Lethbridge in 2024, however, it has lived in Lethbridge at least as recently as 2000, when a specimen of this species was added to the University of Lethbridge insect collection by B. Clark. However, it is now listed by COSEWIC as threatened (COSEWIC, 2019). This bumble bee is very similar in appearance to B. insularis, except that the top of the head is black instead of yellow (Williams et al., 2014).

Bohemian Cuckoo Bumble Bee

Bombus bohemicus

B. bohemicus was not recorded in Lethbridge in 2024, and it is currently listed by COSEWIC as endangered (COSEWIC 2019). B. bohemicus may look similar to B. occidentalis, but because B. bohemicus is a cuckoo bumble bee, females do not possess corbiculae. B. bohemicus can be distinguished from other Lethbridge cuckoo bumble bees in that it will always have some white hairs on the abdomen while B. suckleyi and B. insularis will not.

Conclusion

There is some cause for concern in the bumble bee world. From personal experience, I have found that being out and about in parks and gardens with strange-looking bumble bee survey equipment invites conversations. Time and time again, I heard many fond bumble bee memories, and many concerns that people had been seeing fewer bumble bees in Lethbridge in recent years. Unfortunately, their concerns are not unfounded, as studies have shown that bumble bee numbers are indeed declining worldwide (Goulson, 2010). Further, it is difficult to fully understand the extent of these declines and their effects on particular species due to a lack of data on most species’ abundances (Goulson, 2010).

Recent work has found that citizen science platforms such as iNaturalist* could be valuable for the monitoring of bees, especially large-bodied bees such as bumble bees, which are more frequently observed by civilian scientists (Pereira et al., 2024). Specifically for Canadian and U.S. bumble bees, the Bumble Bee Watch project has been shown to complement traditional scientific observation methods by filling in data gaps and providing new information (MacPhail et al., 2024). In this way, submissions of bumble bee observations from civilian scientists on platforms such as iNaturalist or Bumble Bee Watch could prove valuable for bumble bee conservation as a complement to traditional scientific surveys. By contributing photo observations to these platforms, we can better understand presences and declines of bumble bee species, particularly where traditional surveys are lacking, and especially where more civilian scientists take up this hobby and gain practice (Pereira et al., 2024).

Full "Bumble Bees of Lethbridge, Alberta" Guide

Did you know? OWC has an iNaturalist project that tracks all bumblebees observed in our watershed. Learn more about this platform and our project in this* blog from April 2025.

Unless otherwise noted, credit for all photos in this blog belongs to Jessenia Buzunis-Delagneau.

References can be found in the “Bumble Bees of Lethbridge, Alberta” guide linked above.

Bumble Bees of Lethbridge

Introduction to Bombus

Bumble Bee Anatomy

Common Bumble Bees in Lethbridge