Robber Fly (Efferia spp.)
Detailing the physical features, habits, territorial reach and other identifying qualities of the Robber Fly.
Updated: 8/24/2017; Authored By Staff Writer; Content ©www.InsectIdentification.org
One could mistake a Robberfly from the genus Efferia for some kind of strange black-and-white bee.
Robberflies are considered 'hanging thieves' becaue they use their arms to suspend themselves from twigs and branches and steal a meal from unsuspecting flying insects. A passerby like a bee, wasp or other fly don't see them as they roam. If they are spotted and within range, the Robberfly will chase the flying insect, eventually overtaking them. Once caught, the Robberfly uses its legs to hold the prey and carry it to a nearby plant. It then uses its sharp mouth to stab the victim and then suck out the victim's insides.
They make a loud whirring noise as they fly because they beat their wings so rapidly. The Efferia species male is slightly darker than the female. At the tip of the male's abdomen is black 'bulb' Females do not have this feature; instead they have long needle-like ovipositors, which they use to inject their fertilizes eggs into the soil. It may look like a stinger at first glance, but it is not a stinger. Both genders can be found hanging around in open fields, parks, meadows and other dry areas.