Monday, July 28, 2008

Bumblebee downsizing.

This past April there were large bumblebees visiting the Pieris bush in the backyard. I identified them as Yellow-faced bumblebees, Bombus vosnesenskii. Their size was striking. These were some hefty bees!

Bombus vosnesenskii and fireweed.

I hadn’t seen any Yellow-faces for a couple months, until I was at the pond the other day, where several were foraging among the fireweed flowers. What struck me this time was how small they were compared to the April bees. Even without any means of direct comparison I knew they were smaller, simply because they didn’t seem abnormally big. Explanation? The big bees in April were queens, recently emerged from hibernation, setting about to start their colonies. Now I’m seeing the workers from those colonies. Makes sense to me.

More of the same, showing the lower abdomen (look in lower centre of plant).

Bonus bug:

Spider wasp(?), identity unknown.

And as I was watching the bees, I saw this insect flitting about on the lower leaves of the fireweed. It looks like another spider wasp, Family Pompilidae, but I couldn’t find an image of one with handsome two-tone antennae.

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