LONDON — Near-IR light therapy has been shown to counteract the harmful effects of neonicotinoid pesticides and improve survival rates of poisoned bees.
Researchers at University College London (UCL) used four groups of bumble bees from commercial hives, with more than 400 bees in each colony. Two groups were exposed to a neonicotinoid, Imidacloprid, for 10 days. One group was treated with 670-nm NIR light therapy for 15 minutes twice daily.
Exposure to the pesticide was found to undermine ATP, inducing immobility and reducing visual function and survival. However, bees exposed to insecticide and also exposed to 670-nm light daily showed corrected ATP levels, improved mitochondrial function and significantly improved mobility, allowing them to feed. Physiological recordings from eyes revealed that light exposure corrected deficits induced by the pesticide. Overall, death rates in bees exposed to insecticide but also given 670-nm light were indistinguishable from controls. When Imidacloprid and light exposure were withdrawn, survival was maintained. Another group was given light therapy without being poisoned, and their survival rate was even better than the control group. The researchers found the deep red light did not interfere with bee behavior as bees cannot see light in the NIR spectrum.
"Long-wavelength light treatments have been shown in other studies to reduce mitochondrial degeneration, which results from aging processes,” said professor Glen Jeffery. “It's beneficial even for bees that aren't affected by pesticides, so light therapy can be an effective means of preventing loss of life in case a colony becomes exposed to neonicotinoids. It's win-win."
While light therapy works best as a preventative measure, the researchers discovered it can also be helpful as treatment in response to an incident of pesticide exposure, as long as treatment is started within a couple days of exposure.
"We found that by shining deep red light on the bee which had been affected by the toxic pesticides that they could recover, as it improved mitochondrial and visual function, and enabled them to move around and feed again," said Michael Powner (City, University of London), who led the study while at UCL.
Jeffery’s team is working to develop a small device that will fit into a commercial hive, which could provide an economical solution to insecticide exposure. Researchers at UCL have been studying the benefits of NIR light therapy not only for bees, but also for other animals including humans, particularly to counteract effects of aging and a range of neurological diseases.
"When a nerve cell is using more energy than other cells, or is challenged because of a lack of energy, red light therapy can give it a boost by improving mitochondrial function. Essentially, it recharges the cell's batteries," said Jeffery.
The research was published in PLOS ONE (doi:10.1371/journal.pone.0166531).
The video shows bees exposed to Imidacloprid, a neonicotinoid pesticide. The bees on the right have been treated with red light therapy, mitigating the deleterious effects. The bees on the left are not flying, and their loss of mobility has reduced their grooming capacity, resulting in the fur sticking together and loss of yellow coloration. Courtesy of UCL.