BY JEN VIEGAS in Seeker
Detective work involving honey bees outfitted with ultra-small microchips reveals that a virus once thought to be relatively benign is causing honey bees to live fast and die young.
The pathogen, a covert form of deformed wing virus that is described in the journal Proceedings of the Royal Society B, may even be exerting a form of mind control over worker honey bees.
“It’s possible that the virus has evolutionary interests in manipulating workers to move out of the hive and then maybe transmit the virus to other patches in the environment or cause them to drift to other hives,” author Tom Wenseleers of the University of Leuven told Seeker.
He added that the theory may seem far-fetched, “but is in fact not that unlikely, given that the virus has been found to concentrate in specific centers of the brain that are involved in higher cognitive processes.”
He, lead author Kristof Benaets and their team tracked the movements of honey bees using the microchips — known as RFID tags — that weigh less than .0002 ounces. The little devices, affixed in this case to the backs of bees, are most commonly used to tag items in stores to prevent theft. The new study is among the first to tap the devices for investigating the impact of pollinator viruses.
The researchers found that adult worker honeybees with deformed wing virus often show no outward physical symptoms of the illness, which can otherwise cause crippled wings when victims are infected in the larval stage.
Still, the infected adult workers show bizarre behavior. They start foraging at much earlier ages, reduce their activity levels earlier than other adult workers and then die younger than honeybees without the virus.
Aside from the possible mind control abilities of the virus, the initial fast living of the sick honeybees could be because the pollinators detect that they are ill and react by leaving the hive early in order to avoid infecting their nest mates, Wenseleers explained.
Honey bees, like other insects, have an immune system and can fight off viral diseases, but their ability to do so has been suppressed in recent years. Other research has shown that certain pesticides can weaken honeybee immune systems, as well as diminish bee sperm.
Yet another problem, according to Wenseleers, is “the free trade in bee queens, which are shipped around the world.” If these bees are infected with deformed wing virus, they can easily pass it on to their daughter workers.
Solving the longstanding colony health issue is proving to be very challenging. To prevent the deformed wing virus from spreading, Wenseleers hopes that beekeepers will “rely more on locally acquired bee stocks, to avoid diseases from spreading.”
Since parasitic Varroa mites are also known to transmit the virus to honey bees, efforts to control these pests are ongoing. Wenseleers said that “some beekeepers think that the best course of action may in fact be a very simple one: just let nature take its course and let the bees themselves develop Varroa resistance.”
On the other hand, he added, the agrochemical company giant Monsanto has been trying to develop a method called RNA Interference (RNAi) to combat bee and other animal diseases, including deformed wing virus. RNA is a molecule in the cells of plants and animals that helps to make proteins.
Wenseleers explained that the method relies on mixing synthetic RNA in a sugary syrup fed to bees. The synthetic compound “is designed to bind to specific genes of the pathogen or parasite, thereby preventing it from replicating.” The technique still needs refinement, possibly because the synthetic RNA is not stable enough over long periods of time.
“With further development, though, this revolutionary new method could well have a lot of promise to treat viral diseases, including in crops, livestock or humans,” Wenseleers said.