John Hafernik, a scientist at San Francisco State University, was looking for something to feed a praying mantis in his lab. He found some bees outside his classroom.

“But being an absent-minded professor,” Hafernik told the San Jose Mercury News, “I left them in a vial on my desk and forgot about them.”

A week later, Hafernik came across the vial where the bees were dead. To his suprise however, the dead bees were surrounded by young, developing flies. An adult fly was feeding on the bees.

The parasitic fly is shown on a honey bee.The fly deposits its eggs in the bee's abdomen, turning it into something
like a zombie. The bee then dies. (AP Photo/Christopher Quock, San Francisco State University)

Hafernik believes the parasitic might be a contributing factor to honey bee colony collapse.  Here is why:

• The parasitic fly deposits its eggs into a bee’s abdomen.
• The bee becomes infected by the eggs and begins acting like a zombie.
• It stumbles in circles with no sense of direction, or may be unable to stand at all.
• Finally, the bee leaves its hive and dies.

“It’s the flight of the living dead,” Hafernik said. “[The bees] kept stretching [their legs] out and then falling over. It really painted a picture of something like a zombie.”

"We don't fully understand the web of interactions," Hafernik said. "The parasite could be another stressor. Or it could play a primary role in causing the disease."

Research is continuing.