Friday, June 15, 2012

Pollinator of the Week: A Buzzing Bonanza

Scots Rose & White-tailed Bumblebee
June can be  beautiful month in Edmonton, or so they tell me. In my experience, the beauty comes in small doses, with the breaks in the clouds as rain-laden low after low rolls across. Oh yeah, I know, I'm always whinging about the weather here, but take a look for yourself.
When the sun does break through, though, things start popping. In the first two weeks of June, it is the Scots Rose (Rosa spinonissima 'Grandiflora') that pops the most. Our heirloom monster came with the house and is about 4 meters of spiny canes in every direction. Sometime between June 1st  and 16 June (the cold spring of 2009), the thorny mound becomes covered with large (7-8 cm diameter) single white roses - and bees galore, at least when the sun is shining.
The new, and currently most common, Bombus in town
Wednesday afternoon the sun was shining and the bees buzzing. The most common was also the most recent addition to the Edmonton Bumble Bee Fauna: the White-tailed Bumblebee, variously known as Bombus cryptarum, lucorum, and moderatus. The genetics seems to favour the latter, so that is what I am sticking with.
Red-belted Bumblebee Queen
Although apparently the most common bee at the Scots Rose - and with unusually large workers for this time of year - the White-tailed was only one of at least 6 species of Bumblebee harvesting the pollen and nectar.
Half-black Bumblebee worker
Second most common was old-reliable: the Half-black Bumblebee (Bombus vagans), both queens and new workers. But also present were queens of the Red-belted Bumblebee (B. rufocinctus - thanks to John Ascher for the id), the Tricoloured Bumblebee (B. ternarius), and a single queen each of the Yellow-banded Bumblebee (B. terricola) and what I'm tentatively calling the Black-and-Gold Bumblebee (B. auricomis). The latter seemed more interested in the lilacs, but was not above a blurry dive into a rose.
Maybe Black & Gold Bumblebee
But wait! There's more! A half-dozen or more other bees were also harvesting the bounty.
Halictus rubicundus - Banded Sweat Bee
A large and a small species of sweat bee (Halictidae) were zooming in and out and I'm pretty sure the larger one was Halictus rubicundus. She seems to lack a common name, but I will call her after her most striking character: the Banded Sweat Bee.
Leaf-cutting Bee Megachile sp.
A leaf-cutting bee was also in on the harvest, although collecting pollen on the underside of her abdomen, rather than on the hind legs. Then there were all the mystery bees.
Mystery bee in Scots Rose
Perhaps anthophorines, perhaps andrenids, perhaps halictids. Who knows? I think one may have been a yellow-faced bee and another an Andrena. There was so much rapid buzzing in and out that it was hard to keep track, but at least a dozen types of bee ended up in my notebook.
Probably a Digger Bee Andrena sp.
Alas, bees were not the only animals on hand to share in the bounty and not every bee made it home to its nest.
Digger bee becomes one with Misumena vatia
Oh well, it's not a Disney world in the Home Bug Garden, and there seemed bees enough for flowers and crab spiders.
Small worker of, maybe, B. centralis or flavifrons
Well, yet again, the showers have stopped for the moment and the sun is shining. Time to push through the wet vegetation and see if something interesting is buzzing about.
Rosa spinonissima 'Grandiflora'


  1. I noticed you mentioned B.centralis as a worker. I though that bumblebees were solitary, not social. So much to learn, so little time...!

    A beautiful rose, and in our garden it is these domesticated roses that can be relied upon to bring in the bees. Bigroot Geranium (G. macrorrhizum is also popular with the buzzers right now.

  2. As far as I know, all Bombus are social (or social parasites). They are not perennial, though, unlike honey bees (maybe in the tropics, but they are rare there). So, bumble bees start out as solitary queens in the spring and then form colonies. The first batch of workers are usually very small (moderatus may be an exception or I'm seeing the second batch already) and they tend to get bigger as the season goes on. New queens and drones start appearing in late August.

    The social parasites (subgenus Psithyrus) could be called solitary in that they do not produce workers -- just take over the workers in an existing colony and use them to produce reproductives. But that would be a stretch.

  3. Wow, what a collection! Nicely done.