Light Therapy Could Help Bees Recover From Pesticides

The world’s bees are in crisis, beset by a daunting variety of threats. Humans are at least partially responsible for the bees’ decline, but we’re also hoping to be responsible for their rescue. Now scientists have found one way to protect them. Writing in the journal PLOS One, they report that treating hives with red light can help bees recover from pesticide exposure.

About ten years ago, beekeepers began reporting mass die-offs and disappearances from their hives. In many places, it appeared as though the bees had simply been raptured; hive boxes were empty but there were no bodies to be found.

One of the first suspects in Colony Collapse Disorder (CCD), as it came to be called, was a parasite called the varroa mite. But even the ravenous, invasive mite couldn’t make bees disappear, so scientists began looking for other clues. Their search led them in a number of different directions, including toward a class of pesticides called neonicotinoids. All pesticides are, by design, bad for bugs, but neonicotinoids have an especially nasty effect on bees, causing them to forget to eat and even where they live. They also curtail the production of an energy-carrying molecule called adenosine triphosphate (ATP), weakening the bees and keeping them from flying.

In light of this information, environmental agencies in some countries have banned neonicotinoid pesticides altogether. Others are holding out and leaving the bees to fend for themselves.

But they’re not completely alone. Researchers at University College London (UCL) have been developing a treatment that may help bees bounce back from pesticide exposure. They knew from previous studies that infrared light could help slow and heal cellular breakdown, so they decided to try it out with sick bees.

They set up four hives. For 10 days, the researchers exposed two of the colonies (let’s call them A and B) to a neonicotinoid called imidacloprid, while the other two (C and D) were left alone. During the same period, they exposed hives A and C to infrared light twice a day for 15 minutes.

As expected, the poisoned bees in hive B did not fare well. Their survival rate and ATP levels dropped. With no poison and no light treatment, the unmolested inhabitants of hive D were just fine. But so were the bees in hive A. They were hale and hearty, moving around and living their lives as though they’d never been poisoned. The light was clearly doing them good. It also offered a boost to the healthy bees in hive C, whose survival rates were even higher.

Co-author Glen Jeffery is a visual neuroscientist at UCL’s Institute of Ophthalmology. He and his team were encouraged by their results, and say a simple infrared light in hive boxes could be all that’s needed. Not only does the light help damaged bees heal, but it can even protect those who have never been exposed. It’s “an effective means of preventing loss of life in case a colony becomes exposed to neonicotinoids,” Jeffery said in a press statement. “It's win-win."