Scientists in Northern California believe that a parasitic fly may be to blame for the honey bee die-off that has been observed across the world, The Associated Press
In a study of the bees, the researchers found that this parasitic fly hijacks the bees' bodies, causing them to abandon their hives. The fly deposits eggs into the bee's abdomen, causing the bee to demonstrate "zombie-like" behavior - walking around in circles with no apparent direction. Infected bees then leave the hive at night and die.Live Science
reports that while scientists are not entirely sure how the flies are changing the bees' behavior, they hypothesize that they somehow affect their circadian rhythm. They are also unsure of why the bees leave the hive - as a sense of protection for others or whether they are being forced out.
The flies are the main culprit because this system seems to fit with colony collapse disorder that has been observed in hives - all adult honey bees in a colony suddenly disappear, the news source reports.
However, researchers noted that the flies may not be the only issue in play. In the 31 hives surveyed in the San Francisco Bay area, the parasitic fly was found in about three-quarters. The parasite may also be working in conjunction with pathogens and other stressors to cause the honey bee die-off, they noted in the report.