Some researchers have pointed to the virus and fungus as potential culprits in colony collapse disorder, and hive abandonment is the primary characteristic of the disorder. It may be time, Hafernik said, to consider how the fly parasite fits into the CCD picture.

He said the next step is to find out exactly how the parasite is affecting the bees’ behavior. It is possible, he said, that the parasite is somehow interfering with the bees’ “clock genes” that help them keep a normal day-night rhythm.

The researchers also don’t know if the infected bees are leaving the hive of their own accord, or whether they give off some sort of chemical signal that provokes their hive mates into throwing them out. “A lot of touching and tasting goes on in a hive,” Hafernik said, “and it’s certainly possible that their co-workers are finding them and can tell that there’s something wrong with them.”

The scientists will deploy a range of tools -- from tiny radio tags to video monitoring -- to help them answer these questions and discover ways to protect the hives.

“We don’t know the best way to stop parasitization, because one of the big things we’re missing is where the flies are parasitizing the bees,” Hafernik noted. “We assume it’s while the bees are out foraging, because we don’t see the flies hanging around the bee hives. But it’s still a bit of a black hole in terms of where it’s actually happening.”

Genetic analysis of the parasites confirmed that they are the same flies that have been infecting bumblebees, raising the possibility that the fly is an emerging and potentially costly new threat to honey bees.

“Honey bees are among the best-studied insects in the world,” Hafernik noted. “So at one level, we would expect that if this has been a long-term parasite of honey bees, we would have noticed.”

Colleagues in this study, “A new threat to honey bees, the parasitic phorid fly Apocephalus borealis.” include SF State students Jonathan Ivers, Christopher Quock, Travis Siapno and Seraphina DeNault; SF State Assistant Professor of Biology Christopher D. Smith; graduate student Charles Runckel and Professor of Biology Joseph DeRisi from the University of California, San Francisco; and phorid expert Brian Brown from the Natural History Museum of Los Angeles County.