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Consider a situation where you wake up in the morning and can't grab a cup of coffee, bite into a juicy apple, blend your favorite anti-oxidant filled smoothie, or even buy pure cotton clothes. Pollination by bees and other pollinating insects is essential to our ecosystem and production of all these things we enjoy in every day life- even chocolate. Unfortunately, bee populations are in crisis, partly due to the use of pesticides (as much as 45% decline in commercial bee population since mid-2000s in UK and USA; Greenpeace). According to Greenpeace, pollinating insects contribute to one-third of global food supplies.

A commonly used group of pesticides, called neonicotinoids (or neonics), are chemically similar to nicotine. Neonicotinoids over-stimulate nerve cells in insects, including bees. Over-stimulation of nerve cells results in bee paralysis- they become immobile and eventually die as they cannot forage for food. Also, bees are more likely to choose plants that have been treated with neonicotinoids than those that have not. The European Union and some US states have banned use of some neonicotinoids and recently Health Canada also called for a ban.

When a nerve cell is active it depends on energy to keep going from an organelle called the mitochondrion- when a bee ingests neonicotinoids the mitochondria cannot keep up with the energy production to sustain nerve cell activity and so the nerve cells basically become like a car with a dead battery. The end-point to this is that the nerve cells die, resulting in bee immobility (See our recent blog “Targeting brain power to prevent and treat brain disorders” for more on this).

Researchers at University College London (UCL), led by the lab of Professor Glen Jeffrey in collaboration with Neurexpert CSO, Professor Tom Salt, studied bees in a hive exposed to one of these pesticides (Imidacloprid) and saw that they didn’t fly, or buzz, or respond to someone tapping the hive. Obviously, bees that cannot move are not good for the ecosystem and these kinds of pesticides last in the soil for a long time- contributing to long-term devastating consequences on bee populations. This study, published open access in Plos One, proposes a plausible therapy using near-infrared light, coined photobiomodulation, to prevent death of, and protect, bees exposed to neonicotinoid pesticides.

Light absorbing molecules (cytochrome oxidase) in mitochondria are an essential component of the respiratory chain and essential for cell health, longevity and energy creation. The UCL researchers found that, even though bees cannot “see” near-infrared light, hive behaviour of pesticide-exposed bees was indistinguishable from normal bees when treated with short bouts of near-infrared (deep red) light (670 nm wavelength). They flew about, buzzed and responded to hive taps. Furthermore, the pesticide-treated bees that were exposed to deep red light for short periods of time had lifespans that were inseparable from bees not exposed to pesticides.

And - very importantly for moving forward- the health of the exposed bees continued to be indistinguishable from controls even after deep red light treatment had finished.

When the researchers recorded electrical activity from bee eyes they found that visual responses after pesticide exposure were reduced. Compromised bee vision probably significantly impacts their ability to navigate their environment on top of mobility challenges. Amazingly, this loss of visual function could be rescued if the bees were treated with deep red light- probably because it helped mitochondria produce much-needed energy. Remember that it’s a problem of energy deficiency that stops the nerve cells from functioning and results in cell, and then bee, death. Professor Tom Salt (CSO, Neurexpert) commented that "these studies show the importance of how mitochondrial function can be affected by red light exposure, and highlight the value of electrophysiology in providing a physiologically-relevant read-out of these effects".

Near infrared light could be critical in cell health, longevity and energy production- maybe like the magic potion that, if you could bottle it, could limit aging. Exposure to deep red light in the lab has been shown to improve fruit fly lifespans and studies suggest it could be a potential therapy for patients with age-related vision loss and neurodegenerative disorders, such as Parkinson’s Disease.

This study provides direct evidence for the detrimental effects of pesticides on bee nervous system function and how it manifests itself in bee behavior and survival. BUT it also provides a potential strategy to combat this- deep red light exposure in hives- not only for treating bees already exposed, but, also as a preventative health measure. The study also bolsters the idea that mitochondrial health and eye/ vision health are connected. If you want to know more about how mitochondria function is deeply interconnected with our brain health, and as a diagnostic tool, then you can read about it here.

Since photobiomodulation can maintain bee nerve cell health even when exposed to damaging pesticides, then a simple intervention such as red light sources that intermittently expose hives to near-infrared could be greatly beneficial to bee survival and our ecosystem and global food supplies.

To view the original paper discussed in this blog, "Improving Mitochondrial Function Protects Bumblebees from Neonicotinoid Pesticides" in Plos One, please click here.

The Blog was written by Carolyn Lacey, Scientific Outreach Manager at Neurexpert. To learn more about Carolyn and Neurexpert, please click here.