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Writer's pictureljmarkson

Robber Flies are Ferocious Insect Hunters!

Yesterday, when a robber fly landed on my backdoor window I felt like it wanted to say hi and have its picture taken because it disappeared when I put my camera away!

Unlike the docile crane fly I originally thought this was, it is actually one of the many species of ferocious robber flies that live in Georgia. Below I've shared a few interesting things I learned about these fascinating insect predators. If you click on the highlighted links, there’s even more detailed information about them.

This photo of a robber fly hanging out on my backdoor window makes it look like he (she?) is in suspended animation!
  • Robber flies, also called assassin or stiletto flies, are considered beneficial. They are generalist insect hunters, and will eat a broad range of insects, including invasive ones.

  • These flies are pretty savage hunters and will capture their prey in midair and inject them with enzymes that incapacitate and dissolve the insides of even larger insects, like carpenter bees to make it easier for them to eat.

  • One of the most common names for robber flies is “hanging thieves” because they hang on plants by one or two of their front legs to eat their prey.

  • A variety of flying insects fall prey to robber flies, including biting flies, mosquitoes, Japanese beetles, wasps, moths, bees, dragonflies, and butterflies. Robber flies will even eat yellow jackets and hornets!

  • Cannibalistic robber flies will attack and eat other robber flies, and females will even devour potential mates!

  • As part of the ecosystem, robber flies are a food source for other wildlife including spiders, assassin bugs, birds and even larger robber flies.

  • Larval robber flies live in soil and decaying matter where they eat other insect larvae and worms, and are eaten by ground beetles, centipedes and moles.

  • There are over 7,000 species of robber flies worldwide, 1,000 in North America, and 150 in Georgia!

  • We want robber flies in our yard! Their high biodiversity and predatory activity make them an important member of the ecological food web.

I took this photo last year of this too cool robber fly. For some reason he reminds me of an insect version of a beatnik - he has the goatee and sunglasses, and just needs a beret.

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