A “Zombee” tattoo (by Josh Herrera of Skin Factory in Las Vegas)

More bad news for honeybees: not only do our hard-working black-and-yellow friends have to contend with blood sucking varroa mites, neonicotinoid insecticides, and giant hungry bears, but a new plague has been spreading from the west coast, claiming the life of domestic honey bees.  The Zombie fly (Apocephalus borealis) is a disgusting little hunchbacked phorid fly which has traditionally preyed on native wasps and bumblebees.  Phorid flies, coincidentally, are a successful family of over 400 species of tiny flies which tend to run very rapidly (although they are capable of flight).  The most famous phorid fly (insomuch as that’s a thing) is probably the coffin fly—although the zombie fly is working its way into the limelight too.  Charming!

The parasitic fly Apocephalus borealis on the back of a bumble bee (photo by Kimberly G. O’Harrow)

Like the horrifying parasitoid wasps, the zombie fly uses its syringe-like ovipositor to inject its eggs inside of its victims.  As the larvae hatch they attack the bee’s brain and cause it to behave in bizarre manners—such as lurching around in a random fashion or flying at night (which gets the bee away from the hive and ensures that the fly lavae are not destroyed by the bee’s concerned colleagues).  Bees so affected are mordantly known as “zombees” for obvious reasons.  Eventually the zombie fly larvae pupate into hard little cocoons which resemble grains of rice.  When they hatch they rip through the bee’s body at the juncture of the head and thorax, frequently decapitating the bee.  Sometimes it is difficult to enjoy the beauty of nature.

Adult female Apocephalus borealis fly (image from Core A, Runckel C, Ivers J, Quock C, Siapno T, et al. (2012). “A new threat to honey bees, the parasitic phorid fly Apocephalus borealis”. PLoS ONE 7 (1))

It is unclear to what extent zombie flies are contributing to the decline of honeybees at large–since the flies have not traditionally attacked domestic bees.  Perhaps the death and decline of other native bees has pushed the zombie flies into this new behavior (or maybe they were getting around to it anyway—they sound like thoroughly repulsive customers).  At any rate, beekeepers have a new problem to worry about, and are tracking confirmed instances of “zombees” online at www.zombeewatch.org.