Flying under the radar: encountering bumble bee mimics in the field

This year, I was hired as a bumble bee conservation technician for the Bumble Bee Recovery Program’s spring field season. I was able to learn a lot about where to look for bumble bees, how to identify them, and most importantly, how to catch them! Once you get the hang of it and know what you are looking for, bumble bee queens are relatively easy to spot – they are big and fuzzy with a flight pattern that is fairly distinct compared to other insects. However, there were a few insects that were able to fool me from a distance, and surprisingly, right up-close too! These bumble bee look-alikes, or what are often referred to as bumble bee mimics, are engaged in a phenomenon called Batesian mimicry. Batesian mimicry is a defence mechanism whereby a harmless animal adopts the warning system (such as a colour pattern) of a more dangerous animal. In this way, the mimic gains protection from predators because it is mistaken for something that might pose a threat to them—like the sting of a bumble bee!

On my first day, I learned how to use an extendable net to catch bumble bees off of tall willow trees, and I couldn’t wait until I caught my first bumble bee queen. When I finally caught something in my net, I was excited when I thought it was a bumble bee! However, my first catch in the field turned out to be a bumble bee mimic instead. The insect in my net was a species of syrphid fly (or hover fly); it was fuzzy, with an alternating black and yellow pattern on its body, and I was surprised to see how much it resembled a bumble bee (although comparatively small to a queen).