My zombie flies: pets I could do without

My plan was to split my largest hive before I left town for a week. Although my husband was willing to deal with a swarm if necessary, I decided it was better to save him the trouble.

Before I could begin, I had to prepare a place to put the split. I decided on my one dead-out, a hive where the colony had perished suddenly in March. It is embarrassing to say that the hive starved, but I’m sure that is what happened. I had been feeding all my colonies once every two weeks since the unseasonably warm weather arrived, but while that worked for my other hives, this one didn’t make it. It was fine on March 4, but by the time I opened it for the next feeding on March 16, there wasn’t a speck of food left and everyone was dead.

As soon as I found the colony dead, I closed up the hive so predators couldn’t get in. Otherwise, it sat there unattended until April 25 when I decided to clean it up and use it for the split.

I began scraping the tops of the frames in the highest of the three brood boxes. I saw some funny-looking cocoon-like things sprinkled around the bars, but I just scraped them into the grass. Something, though, bothered me about them. After a few minutes I stopped what I was doing and looked for more. They were easy to spot since there were so many. It occurred to me that they looked like the photos of zombie fly pupae I’d seen on the website. I decided to collect some and take photos.

The most frustrating thing was trying to upload my findings to ZomBeeWatch. Their data collection software wasn’t set up for finding pupae in a dead hive on dead bees in winter not near a light source. Irritated, I sent an e-mail to the contact person and asked what to do.

In the meantime I finished cleaning the hive. The only place I found the fly pupae was near the dead cluster of bees in the top of the top brood box. I searched in the two lower boxes and I sifted through the debris on the bottom board, but found no more pupae.

A few hours later, I received an fascinating e-mail from John Hafernik of San Francisco State University. John is the person who first discovered that the parasite, Apocephalus borealis, had begun infecting honey bees. In his e-mail he said he had forwarded my photo onto Brian Brown at the Natural History Museum of Los Angeles County. He said that both he and Brian believed my sample looked like A. borealis pupae. He said that if that were true, it would be the very first evidence of the fly overwintering in a failed honey bee hive. He asked me to keep the pupae isolated and watch what happens. Nothing like being famous for all the wrong reasons.

I put everything in a mason jar and asked my husband to watch it while I was gone. Yeah, I know—instead of worrying about swarms, he now had to worry about parasitic flies instead.

During a conversation with John, he asked me to say hello to Ramesh Sagili, Assistant Professor of Horticulture, at the Oregon State University Honey Bee Lab. This turned into an opportunity for me to see confirmed samples of A. borealis pupae as well as an adult fly—something that has been very helpful.

Now that I’m home again, I have mason jars lined up containing all manner of zombie flies. On Sunday May 5, I got my first adult fly, on Monday I got another, on Tuesday three more, and three so far today. I’m operating a regular zombie fly hatchery in my kitchen. Right next to dinner I have jars of dead bees, jars of pupae, jars containing flies of various ages, and jars of dead flies, too.

I still need to submit photos of my adult flies for the final confirmation of their identity. This is turning into a nightmare; I’ve taken dozens of photos where you can’t see much. I’m probably going to end up sending the dead flies to OSU and let them work it out.

Still, it’s been a fascinating ride. Yesterday I posted a question and answer page about zombees and zombie flies, and I urge everyone—especially beekeepers—to get involved with and help gather information about this little-known threat to honey bee health. I signed up almost a year ago and never expected to see a zombie fly in my entire life. Now I’m raising them in my kitchen. You never now where those small acts will lead.



Possible zombie flies hatching in mason jars.

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  • Great find! I am the Kent beekeeper that found the fly last fall. I had checked out my deadouts and had not found any evidence of the fly. I have also been trapping bees with a light trap this spring and have yet to get a positive sample.

    • Nice to meet you, Mark. I remember reading that zombees were found in Kent. I put out light traps last year and didn’t find anything. I’m getting ready to do it again.

  • Facinating Rusty. So glad that you are part of this unique research. I can just picture what your kitchen counter looks like! I haven’t seen any more yellowjacket queens lately so I think you got most of them. Thanks.

    • Linda,

      I got warmed up at your place. When I got home, I had huge yellowjacket queens waiting for me! It was good practice.

      • Rusty, how are you trapping the yellowjacket queens? I’ve had Rescue brand traps out since it was warm in March and have caught 8, (2 yesterday) but some queens are able to resist them.

        And thank you for another fascinating blog! I’ll send this to our bee club president with recommendation that he encourage club members to sign up for the zombee watch. Boise is not that far from WA!

  • What a coincidence, I found some zombified bees attacking my porch light a couple days ago.

    Can you post pictures of the pupae you found in the hive?

    You probably have a nicer camera with nicer lenses than me, but I was able to get decent detail by holding a 10x hand lens between my camera and a (dying) bee I was trying to take pictures of. If that’s not enough magnification, I was planning on using my 60x hand microscope to take pictures of the flies if any hatch out of my zombie bees.

  • So, from your blog post and some of the comments, I think it’s pretty safe to assume they’re widespread. I’m happy for your brush and participation with a scientific capture data call, but did you get a chance to probe from any of the researchers for any further information regarding actual threat to a hive from “zombee” flies? Are they enough of a pest to cause any real hive loss?

    • I think your answer is on the Q & A page. All by themselves the flies are not a substantial threat. But in combination with other parasites, pathogens, predators, and poisons, they make it even harder for colonies to thrive.

  • That’s…kind of gruesomely awesome. And fascinating, in an “eeewwww” sort of way. Also I am going to make my husband read this post, because he thinks it’s bad when I take off and leave him milking a goat. At least I don’t have him raising parasitic insects!

    As an aside, I did my first inspection on my new package yesterday, two weeks after releasing the queen. The bees are thriving and also behaving like they’ve read exactly the same information on top-bar beekeeping I have — they’re drawing nice straight comb precisely aligned on the top bars. There was brood in all stages of development, from egg to capped, as well as cells of pollen. In fact they’d made at least a good start on all 8 of the top bars I originally gave them, so I gave them 2 more bars, filled up their feeder, and left them to it.

    I wanted to say thank you to you and the commenter community here for your support & encouragement during my Package Saga this spring. It’s really nice for a brand-new beekeeper like me to feel like more experienced beekeepers are backing her up. Rusty, you and your commenters are the bees’ knees!

  • Interesting. And where, may I ask, are you located? I’ve been watching their map light up like a Christmas tree since it launched.

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