Light Treatments Enhance Bumblebee Survival

Published: December 20, 2016

Declining bee populations are a concern for fruit and vegetable crops that require insects to pollinate flowers. Researchers at the University of London recently found that treating bumblebee colonies with red light had less mortality than those that did not receive a red light treatment at 670 nm. Another important finding was that bees treated with imidacloprid insecticide were protected by exposing them to infrared light. Bees exposed to red light were active and flew normally, whereas insecticide-treated insects did not fly and were silent when disturbed.

Imidacloprid is a pesticide that can be applied to control sucking insects, such as aphids, thrips, whiteflies, Japanese beetles, termites, etc. on landscape trees, turfgrass, and fruit nut trees. Imidacloprid is classified as a neonicotinoid pesticide, which can overstimulate bumblebee nerve cells, resulting in impaired visual functioning, insect immobility, and eventual death because they are unable to feed.

In this experiment, four treatments were used. Two groups of bumblebees were treated with insecticide for ten days, with one group also receiving 15 minutes of near infrared light at 670 nm twice daily. The other two treatments were no red light exposure (control) or the infrared light exposure for the same time period. The mobility of the bees treated with insecticide declined rapidly, as well as their survival rate. However, the red light exposure corrected the insecticide-induced damage to the bees and allowed them to survive just as well as bees that had not been treated with imidacloprid.

As a result of this study, researchers are now developing a red light-emitting device that can be placed within a hive to help save bees. Such a device might also be used in the future to prevent premature mortality when bees are inadvertently exposed to neonicotinoid pesticides, as long as red light treatment begins within a few days after the insecticide is applied.

For more information, see journals.plos.org.