Apocephalus Borealis

Apocephalus borealis is a species of North American parasitoid phorid fly that parasitizes bumblebees, honey bees and paper wasps. These flies are colloquially known as zombie flies and the bees they infect are colloquially known as zombees. The association with honey bees has so far only been documented from California, South Dakota, Oregon, and Washington; elsewhere, they are primarily associated with bumblebees. Female flies lay their eggs in the bees, and as the larvae develop, they attack the bees' brains and cause them to become disoriented, fly at night and exhibit other unusual behaviors. These behaviors eventually result in the death of the bees, but increase the survival and spread of the phorid flies. Mature larvae emerge from the junction of the head and thorax, often decapitating the bee (the generic name Apocephalus refers to this grim result). A. borealis has been suggested as a possible vector promoting the spread of the pathogens responsible for colony collapse disorder.

  • Ovipositor of an A. borealis

  • Female A. borealis ovipositing eggs into the abdomen of a worker honey bee

  • Two final instar larvae of Apocephalus borealis exiting a honey bee worker at the junction of the head and thorax

  • Adult female A. borealis

  • Head of an A. borealis