Parasitic fly dooms bees to death by maggots.

Researchers have identified a new enemy that ought to strike fear in the hearts of honey bees: A tiny fly that lays its eggs in the bee abdomen, giving rise to maggots that wiggle out near the victim's head.

http://news.sciencemag.org/sciencenow/2012/01/parasitic-fly-dooms-bees-to-death.html