More Squamish Bumble Bees …in honour of World Bee Day

In honour of World Bee Day, May 20, 2023.

BC is home to more than 600 species of native bees. Most can’t be identified by sight or photos so only scientists working with microscopes get to know them well. Our best chance to start to get to know our bees is by watching for the familiar big, colourful, noisy bumble bees. The big queens started to emerge in late March and their young can usually be seen from late May through August. To find them, go where the flowers are.

Some time ago, we shared details about the four most common bumble bee species we see in Squamish. Seven other species have been observed here recently,  but it would be a stretch to call them regulars.

Our fifth most common bumble bee is Bombus sitkensis (Sitka bumble bee). These are long-haired black and yellow bees, distinguished by paler, tawny hairs at the tip of the abdomen.

A female Sitka bumble bee, seen in a garden in Brackendale in mid-August. Only female bumble bees and honey bees collect pollen in sacs on their hind legs.

You’re next most likely to see B. flavidus (Yellowish cuckoo bumble bee ), one of two species of cuckoo bumble bees we have in Squamish. Females of cuckoo species lay their eggs in nests of other bumble bees and they don’t have to gather pollen to feed their young.  Cuckoos are distinguished from other bumble bees by their hind leg tibia, “uniformly convex and densely hairy”.

Bombus flavidus, a cuckoo bumble bee, can be identified by a small patch of orange hairs at the tip of the abdomen. This bee was at Quest in early July.

B insularis (Indiscriminate cuckoo bumble bee) shows up next most often. It’s another black and yellow bee and is hard to identify. In many cases, the cuckoo bumble bees seem to have abdomens that are longer and more tube-shaped than other bumble bees.

This Bombus insularis gives you a sense of the longggg abdomen and shows the convex hind tibia. It was in Brennan Park in late September.

B vancouverensis, our Vancouver bumble bee, is next on the list. There are two subspecies and it takes an expert to tell them apart. The most useful photos for identifying bees are taken from the side, as most of these are. Sometimes, there is a feature that requires a straight-on shot from the back to identify.

A Vancouver bumble bee foraging in Garibaldi Highlands. A back shot is usually needed to identify this species because of the characteristic black notch on the back of the abdomen. The raised leg  at left is thought by some to be an indication that the bee is anxious.

B sylvicola (the Forest bumble bee) has been observed here several times but recently confirmed as such just once. It is similar to other bees we see here and even experts disagree on the fine points of identification. The yellow hairs on the head, thorax, and abdomen are very pale.

The Forest bumble bee is not usually seem in our area. It is considered a boreal-alpine species. This one was at Quest in mid June, in a cleared area which has since become a residential neighbourhood.

Another bee seldom seen here is B rufocinctus (Red-belted bumble bee). Like many of our bees, it has several colour forms and the males can be especially hard to identify.

This Red-belted bumble bee was foraging in our SES pollinator garden in mid-July.

And finally, to end our Squamish top 11 bumble bee hit parade, we have a B vagans (Half black bumble bee) queen who was out of her expected range. There is a sad side to the story of this bee, as there were probably no males to mate with her. That meant that, even if she found a place to hibernate, survived the winter, found food in the spring, and built a nest, she would not have been able to lay fertilized eggs.

This Half-black bumble bee queen somehow strayed here from the Interior. She was foraging on an aster in Garibaldi Highlands in late September.

All photos have been posted in iNaturalist and were identified to species level by a foremost bee taxonomist who lives in Singapore.

Happy World Bee Day.

Banner photo:   These bees are likely the same species, Bombus vosnesenskii (Yellow-face bumble bee), and are the most commonly seen bumble bees in Squamish. Both are workers (female) as we can tell by the pollen sacs on their hind legs. The colour of the collected pollen varies, depending on the flowers being visited. The bee on the left is much larger: this indicates that she had a more ample food supply as a larva.