by Sandy Garland
The other day, Berit sent me a photo of a bumble bee carrying another one. She wondered about this behaviour: why? how?
Large “bumble bee” carrying a smaller one. Photo by Berit Erickson.
I posted her cell phone photo on Facebook, in the Insects and Arachnids of Ontario group, and was astonished at the response. This was not a bumble bee at all! It was immediately identified (by Brian Robin – thanks!!) as a robber fly.
Jeff Skevington (an entomologist at Agriculture and Agri-food Canada) added: “The robber fly looks like Laphria thoracica to me. They use their camouflage as protection from predators but also in a more aggressive way to hunt bumble bees. Nice that you got to see this!”
Try Googling Laphria thoracica and you will be amazed at how much this fly looks like a bumble bee. In the photo below, you can see that the robber fly’s eyes are too large for a bee, and I assume it has quite different mouth parts, but those are not features easily seen while these creatures are flying around.
Photo from BugGuide, showing identified Laphria thoracica preying on a Bombus sp.
Kudos to Berit for her observation skills and quick work with her cellphone camera.
We have one (or more) visiting our gardens this year. I, too, thought a bee was preying on a Japanese beetle and went online to find out it is a good robber fly. Fingers crossed it continues that activity and leaves the bees alone!!
Didn’t mean to write “good”!! I have no idea other than they are another pollinator.