Sunday, June 16, 2013

Bumbling with Bombus: Chives, Bumblebees & Corrections

Three queens of the Tricoloured Bumble Bee at Chives flowers
As herbs go, Chives (Allium schoenoprasum) isn't one of my favourites. I find it rather mild and usually too tenuous for my palate. As flowering onions go, though, Chives is attractive and reliable. Even better, the bees love it. On Friday, one of my patches of Chives in the country (at Gopher Hill) had a dozen bumble bee queens nectaring.
Also known as Orange-belted Bumble Bee Bombus ternarius
The most abundant of these bees, and probably the easiest of all Edmonton area bumble bees to learn, was a half dozen Bombus ternarius the Tricoloured Bumble Bee. The only other Bombus here with a pair of orange bands between two yellow ones on the abdomen is Hunt's Bumble Bee (B. huntii) and this bee lacks the black triangle pointing back on the thorax and has yellow hairs on the head and face (usually black in ternarius, as above, but not always).  The black triangle is a 'key character' amongst the orange-banded bees.

Hunt's seems to be fairly rare here, but the Tricoloured is very common. In the foothills and mountains, e.g. around Calgary, the Forest Bumble Bee B. sylvicola can look very similar, but usually has two yellow bands behind the orange ones.
Half-black Bumble Bee Queen Bombus vagans or rufocinctus?
More easily confused are the two Half-black Bumble Bees that we have in Edmonton, the 'true' Half-black (B. vagans) and the Perplexing Half-black (B. perplexus - aka Confusing Bumble Bee). I've buggered these up before, but now can usually tell them apart. The local B. perplexus seems to arrive earlier in the spring and has only a small, circular area of black between the wing bases and the yellow on the side of the thorax is interrupted by black. Bombus vagans has more extensive black between the wing bases and uninterrupted yellow under the wings - and often some yellow hairs on the posterior abdomen (nice character when present). [Update - and just to keep us guessing, the ever variable Bombus rufocinctus also has a half-black morph.]
Perplexing Half-black Bumble Bee queen Bombus perplexus

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