I Spy with my Little Eye... Tons of Robber Flies!

Robber Fly
Photo Credit: Bart Drees

I was overwhelmed today as I took a walk in the sun and the number of robber flies buzzing around!  You'll probably notice them too, if you spend a little time outside this spring and through the summer.

I'm seeing a grey colored robber fly at the moment (pictured to the left), but later on, as it gets warmer, I'll start to see the bumble bee mimics.

Robber flies are beneficial insects, acting as predators and eating all sorts of insects out of the sky.  But, they aren't picky about what they eat.  They are known to eat up honey bees and camp outside their hives to catch them as they fly past.  The bumble bee mimics will also eat up bumble bees.

You can tell a robber fly from other insects it resembles by looking at the eyes.  Flies have huge eyes that are almost triangular in shape and can almost touch at the top of the head.  The shape of fly eyes are a giveaway for their identification. Robber flies also look like they have mustaches with fuzzy faces and generally fuzzy bodies as well.

Robber fly
Photo Credit: Bart Drees

Last summer, I had a robber fly that sat on a fig tree, next to a blooming shrub that was always overwhelmed with bumble bees.  Every time I walked past that fig tree, that darn robber fly had a bumble bee in it's grasp.  I let this go on for a week or so before I had to put an end to it and smoosh the robber fly.  I like my predator insects, but I love my pollinators more!

My prediction for why robber flies are so active at the moment is because their food source (other flying insects) are out and about right now and the feeding is good!