Robber Fly – Laphria thoracica
Family Asilidae – Robber Flies
Live robber flies photographed at northern Illinois. Size = 25mm / deer fly prey size = 10mm
The backwash from this sucker’s prop almost knocked me down yesterday when it did a close fly-by with a stunned deer fly held tenderly in its front claws, impaled on its proboscis. This is the largest (and in my opinion most stately) of the Laphria complex flies, a truly magnificent creation.
Before I began photographing insects, I had no idea such a thing existed. Now it is my ardent wish every time I’m in the field for an opportunity to watch one of these clever creatures at work.
For me, such a spectacle is every bit as fascinating as watching a lion or cheetah capture and consume a large mammal; a less dangerous pursuit certainly, accessible and inexpensive!
Male Bumble Bee
Female Robber Fly
The Laphria complex flies are convincing bumble bee mimics. This evolutionary adaptation allows them to reap the benefits of aposematic (warning) coloration without the high metabolic cost of constructing and maintaining a venom-delivery system.
Reference: Bugguide.net Laphria thoracica