This robber fly was perched on a tough bully (Sideroxylon tenax) at Treasure Shores Park when we visited there on June 3, 2017. Robber flies belong to the family Asilidae. Florida has more than 100 species, and nearly 1,000 species are found in North America.
Check out the characteristic divot between their enormous compound eyes!
Also known as assassin flies, robber flies seize their prey in flight and use their mouthparts to inject their saliva which contains neurotoxic and proteolytic enzymes. The prey is quickly immobilized, and the proteolytic enzymes begin to break down the protein of the prey.
The robber fly returns to its perch to consume its liquified meal. Robber flies generally perch in sunny spots, and the robber fly pictured above was along the sidewalk next to the parking lot in a tough bully that was full of pollinator-attracting flowers.
Robber flies are opportunistic feeders, and different species perch at different heights. This robber fly was perched about 4 feet off of the ground.
A small leafcutting bee (Megachilidae) cut a small circle from the tough bully leaf pictured above. Perhaps, the leafleting bee became the prey of the robber fly.