Biologists at San Francisco State University are tagging radio trackers onto zombie-like bees infected with a fly parasite to find out more about species population decline.

Bees that are infected with the Apocephalus borealis fly abandon their hives and congregate near outside lights, moving in erratic circles on the ground before dying. This parasitic infection was discovered last year by SF State biology professor John Hafernik and described in a PLoS One paper.

Hafernik and his colleagues are trying to find out how much of a threat the emerging fly parasite might be to the health of honey bee colonies, or if the parasite is linked to the colony collapse disorder that has devastated bee populations in the United States and Europe.

The team is tagging infected bees' thoraxes with transmitters the size of "a fleck of glitter" and then monitoring their movements in and out of a hive on the biology building. Laser readers at the entrance to the hives interact with individual trackers. They are also monitoring other hives nearby to check for signs of the parasite. They are inviting members of the public to get involved through the ZomBeeWatch website. Visitors can upload photos of suspected infected bees to help track the spread of the parasite.

It's important to monitor the comings and goings of bees to understand the progression of the parasitic infection, particularly how long it takes for affected bees to abandon the hive. The original paper found bees disoriented and dying at night, but researchers are keen to find out whether the infected bees only leave the hives to fly in the dark.

Christopher Quock, an San Francisco State graduate biology student, said: "Hopefully in the long run this information might help us understand how much of a health concern these flies are for the bees, and if they truly do impede their foraging behavior. We also want to know whether there are any weak links in the chain of interactions between these flies and honey bees that we could exploit to control the spread of this parasite."

The team also wants to study how the infected bees are treated by uninfected bees. Are they expelled from the hive? Or treated with aggression by other workers?

Biology professor Andrew Zink explained: "If enough of the parasitized bees do the wrong 'waggle' dances to send unparasitized foragers off in the wrong directions for food, or distract unparasitized foragers through antagonistic interactions, the hive's productivity could falter."