Parasites spark swarm of zombie bees
California infestation grave, declare buzz boffins
Researchers have found a type of parasite that turns bees into zombies, causing them to exhibit strange behavior before dying.
The discovery was made by accident, after San Francisco State University professor of biology John Hafernik collected some bees he found outside his office so that he could feed them to a praying mantis he had collected on a recent field trip.
“Being an absent-minded professor, I left them in a vial on my desk and forgot about them. Then the next time I looked at the vial, there were all these fly pupae surrounding the bees," he told AFP.
After zombification, the bee dies and
its murderous parasite burrows free
The parasites were identified as Apocephalus borealis, a phorid fly native to North America, and they attack bees by injecting eggs into their abdomens. Once hatched, the parasites kill the bees within a couple of weeks and emerge from the body when they have finished feeding – but it’s the behavior they induce in bees that scientists have found fascinating.
Infected bees exhibit jerky limb movement and general weakness, then leave the hive and congregate around bright lights – behavior more akin to moths. The scientists are trying to determine whether the bees leave the hive of their own accord, or are forced out by healthy members of the swarm.
"When we observed the bees for some time – the ones that were alive - we found that they walked around in circles, often with no sense of direction," said Andrew Core, a graduate student in Hafernik's lab. "They kept stretching [their legs] out and then falling over. It really painted a picture of something like a zombie."
The zombie problem looks to be severe, with infected bees found in 77 per cent of the samples collected in the San Francisco Bay Area. The team suggests this might be one cause of the collapse in bee populations seen in the last five years. Mobile phones have been fingered as one culprit, but scientists are coming to the conclusion that more than one factor must be involved. ®