Watch out for an invasion of ‘ZomBees’ this Halloween

Picture this: An alien creature lays its eggs inside your body. You begin to feel terrible pain — so much pain that you can’t function or think. You writhe on the floor in agony. Finally — mercifully — you pass out. And you never wake up. It’s all over.

Sounds like a scene from a horror movie, right? But if you're a honeybee, it isn’t make-believe. Honeybees are being attacked by a small, deadly creature called Apocephalus borealis — aka, the Zombie Fly.

“The Zombie Fly is a tiny parasitic fly that lays its eggs inside of honeybees,” explains Lila Higgins, manager of citizen science at the Los Angeles Museum of Natural History. “They find a honeybee, latch onto its abdomen and then use their … needle-like ovipositor to inject an egg into the bee.”

The Zombie Fly lays multiple eggs. The eggs hatch inside the bee, and the larvae start eating its insides. Then, seven days later, maggots start to emerge from a hole they’ve made between the bee's head and thorax.

It's a gruesome sight.

Not surprisingly, infected bees exhibit erratic behavior. “After an individual honeybee gets parasitized by one of these flies, it has a very hard time acting normally. It’s going to cause some discomfort having your insides eaten while you’re still alive,” Higgins says, to put it mildly.

The Zombie Fly was first identified early in the 20th century, but until recently scientists thought it only infected certain wasps and bumblebees. But a discovery in San Francisco in 2011 revealed the Zombie Fly had begun targeting honeybees. Up and down the west coast of the US, bees are leaving their hives, flying around at night and then suddenly dropping dead.

Higgins and other researchers are enlisting citizen scientists to help figure out exactly where these flies are infecting honeybees. So if you spot a honeybee acting strangely, collect it, put it in a vial and watch to see if any maggots come out. Then submit your data to the ZomBee Watch website.

You may be grossed out, but at least it's for a good cause — and a self-produced Halloween horror show.

This story is based on a video produced by Christian Baker for PRI's Science Friday with Ira Flatow.