Zombie Bees Are Here
When I thought I had a “pretty good bead” on beekeeping, something else comes along. Isn’t that the way things go? Now I have to watch out for Zombie Flies! They are turning our honey bees into Zombie Bees or Zombees!
Before you go running to grab a silver bullet, wooden cross or garlic necklace, let me explain.
Zombie bees is the term being used to describe honey bees that are infected by a parasitic fly. This problem was first noted in California around 2008. A bug loving biologist, John Hufernik, became aware of strange honey bee behavior. He was finding dozens of dead honey bees near outside lights each morning. And, this was happening even on cool frosty mornings.
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Honey Bees Don’t Fly at Night
Honey bees are attracted to light. But, it is unusual for them to fly at night. They use UV and polarized light to navigate and are “blind” without the sun. However, bees will leave the hive if disturbed by a predator after dark. This is why you don’t want to be the one holding the flashlight when moving bee hives at night! (They are not attracted to red light though so that is a good substitute.)
Zombie Bees Leave the Hive Never to Return
West Coast researchers and beekeepers noticed honey bees leaving the hive at night. Not the total population of the colony, but individuals would leave. They would fly to a light source, even if it was not in the close to the hive.
Here, the bees would buzz around the light until they died. Somewhat like a “zombie that staggers around after dark – never to return to their home”. You may find disoriented dying bees crawling on the ground under the light at dawn.
Tools of the trade
Zombie Bee Parasite
What is causing this strange bee behavior? The culprit is a parasitic fly, Apocephalus borealis. Not a newcomer to the United States, this fly is native to most of North America. Previously known to prey on bumble bees, honey bees have not been a known host.
Now, we know they are infecting honey bees. Has this been going on for a long time or is it a new development? We do not know.
Zombie Flies Killing Bees
Let’s investigate the parasitic fly life cycle.
An adult fly lands on the back of a honey bee. She sticks her ovipositor (egg-tube) into the abdomen of the bee. Eggs are deposited inside the bee where they hatch into larva.
Fly larva feed on the inside of the bee. Organs and tissues are consumed by the developing fly larva. The health of the infected honey bee continues to deteriorate.
In the later stages of infection, the host honey bee becomes increasingly agitated. She is also attracted to light at night and will fly from the hive. (We dont know why.)
The bee will hover around the light until she dies. You may find a file of dead bees at the base of a lamp post.
When the fly larvae have completed their growth cycle, they will leave the bee’s body and pupate. Up to 15 fly larvae may emerge from a single honey bee! After pupating, adult flies emerge from the cocoons and the process repeats.
How You Can Help With Zombee Research
There is nothing the beekeeper can do to protect honey bees from parasitic flies. Not every bee in the colony will become one of the Zombie bees. At this time, researchers do not know what role zombie flies and zombees play in colony failure. But you can help with the research endeavors.
A citizen scientist project at zombeewatch.org is tracking the spread of Zombees. You can help by monitoring bee conditions in your region. Their website will give you detail instructions on how to get involved. Also, they have information on how to construct light traps and collect specimens.
Light Trap Tips for Zombie Bees
Do you see honey bees flying around lights at night? Or trying to get in the windows of your home when the lights are on inside?
Following the website directions (zombeewatch.org), construct a light trap. These are simple to make with such items as a plastic jug and safety light using a compact fluorescent bulb. Don’t place the light trap close to your hives – they should be well away. You do not want the light to shine on the entrance of the hives. You may encourage bees that are NOT Zombees to come out.
How Do You Know If You Have Zombie Bees?
Any bees that you catch should be collected with tweezers or forceps – don’t touch them. Be careful dying bees can still sting. Transfer the dead bees into a sealed container and place away from the sun. Check periodically for small brown pill shaped pupae. They look like small pieces of brown rice to me. The pupae should appear between 5-14 days after collection. In another 15-28 days you may see flies.
Report your data to the zombee watch program. It is important to their research to learn your results wither positive or negative.
Can Zombie Bees Infect Humans?
No, the parasitic fly does not prey on humans. It will only lay eggs on or inside insects. Currently, it is believed that the bees become infected while away from the beehive.
Will this honey bee pest become a major killer of honey bee colonies? Will it be another “mite-type” issue that beekeepers must struggle to control? How many honey bee pests can our bees deal with and survive?
We don’t know how big an effect this parasitism has on a bee colony. But of course, it is not a good thing. Beekeepers need to be aware of the problem but not overly dramatic.
Researchers continue to study the problem and you can help. There are many parts of the United States still in need of monitoring. This is a great opportunity to help the beekeeping community. And it is open to beekeepers and non-beekeepers.