The Real ZomBee Hunters 

By R. C. Orrell

When John Hafernik was six years old he became fascinated by insects like the Monarch butterflies that passed through his backyard in central Texas on the way to their winter migration in Mexico.

Today, Hafernik is a Professor of Biology at San Francisco State University where he studies the evolution, behavior, and conservation of insects, including honey bees. “Honey bees are a European species that have been introduced to the U.S., but they are very important to us now,” he says. According to the U.S. Department of Agriculture, about one out of every three mouthfuls in our diet comes directly or indirectly from honey bee pollination. So when Hafernik saw some honey bees acting strangely, he collected samples. What he didn’t know at the time was that he had discovered ZomBees

It all began in 2008, when the scientist noticed something odd while walking in the front of the biology building on campus. “I saw some honey bees on the ground and they were kind of looping around in circles, disoriented, and acting strangely.” He scooped up a few of the bees to feed to some praying mantises he had collected in the field. But one day he forgot the vial with the honey bees on his desk and a week or so passed until he noticed it again. When he finally picked it up, there was a surprise waiting inside. “I noticed these little brown pellet-like things in the vial and these were the pupaeof flies. These bees had been parasitized [infested with parasites] by some kind of fly.” 

How did the bees get infected in the first place? Well, the answer is kind of gross. A tiny fly lands on healthy bee and uses a stinger-like appendage to lay eggs inside the bee’s abdomen. The bees leave their hives when the maggots are still very small and die shortly afterwards. After the bee dies, the larvae continue feeding for five to seven days and then emerge from the dead bees and form pupae. 

Back in the lab, Hafernik let the pupae complete their lifecycle for another four weeks and recognized them as phorid flies. “Phorid flies are a group of flies that most people haven’t heard of, but there are actually 4,000 species of these flies worldwide,” he explains. He reached out to specialist Dr. Brian Brown at the Natural History Museum of Los Angeles County, who confirmed the flies were of the Apocephalus borealis species native to the U.S. Also known as “zombie flies”, these insects typically infect bumble bees and yellow jacket wasps, but as far as Brown knew this was the first timethey were infecting honey bees. 

Wondering what might be going on, Hafernik checked with honey bee expert Dr. Eric Mussen at UC Davis who told him there were reports from folks about honey bees coming to porch lights at night and acting strangely. Hafernik went back to where he originally found his bees, and sure enough, the spot was under some lights! But what was making the bees act so strangely? “The pupae could be exuding chemicals that affect the bees nervous system and behavior,” says Hafernik. “We don’t know for sure.”

Hafernik enlisted some students to help track the location of infected bees. Together they created a web site called ZomBee Watch where “citizen scientists” could observe and report back their findings from around the country. Even young kids can become “ZomBee Hunters” says Hafernik. “If they are really young, like five or six, they need supervision by parents to make sure they are handling the bees carefully so they don’t get stung. I know of kindergarten classes that have been involved with the supervision of their instructors.” 

For more information on how you can become a ZomBee Hunter and citizen scientist, ask your parents or guardians to visit

How to Spot a ZomBee

  • Honey bees that leave their hives at night.
  • Attracted to nearby lights. 
  • Sometimes found wandering around on the ground in a disoriented fashion. 
  • Not all honey bees that come to light at night produce parasites.  

Dangers to Honey Bee Hives

Varroa mites (the biggest threat)

Other types of mites  


Fungal infections

Exposure to pesticides

Zombie flies 

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