Red-footed Cannibal Fly

You won't want to mess with this one. Some of the robber flies are truly beastly-looking insects, and the Red-footed Cannibal Fly, Promachus rufipes, is one of them. Robber flies are highly predatory, and as Kenn Kaufman aptly notes in his book Field Guide to Insects of North America, they are "...to other insects what falcons are to other birds".

As with so many insects, too little is known of many species' life histories and distribution. I took these photographs in and around prairies in Adams County over the past few weeks, and have seen this species there on several visits. It's the only place that I've noticed them, but perhaps they are more widespread. Whatever the case, the Red-footed Cannibal Fly is an amazing insect. Big, the size of a huge wasp but much more bulked up, they hunt patiently much like flycatchers or some dragonflies. Sitting tight on a prominent perch, the cannibal fly waits for suitable victims to fly by. With eyes like this, they don't miss much. Rather tame, they will allow close approach if you are careful in your movements. Then, you can watch the insect tilt its head about as it watches potential prey wing by, waiting for a good victim. When it sees something it likes, the cannibal fly dashes out after it like an F-16 scrambling after enemy aircraft and seizes it in those long legs, wrapping the victim tight and injecting it with its proboscis-like mouthpart.

There is little hope of escape once the prey has been ensnared by those powerful legs reinforced with stiff raptorial spines. Soon, the paralyzing chemicals that the fly injects into the victim's tissue goes to work, and paralyzes it. Acid-like, the toxins break down and liquify the innards of its meal, and eventually the cannibal fly sucks out the contents just as we would tap the sweet liquid of a chocolate milkshake through a drinking straw.

The Red-footed Cannibal Flies are watching, always watching. I'll tell you this, if I were some small and relatively defenseless bug, I would not want to bumble into the sights of this thing. Species in the robber fly family are some of the world's fiercest insects, and larger species have even been known to take down hummingbirds, allegedly.