The original inventors of blue light-emitting diodes (LEDs) might have won a Nobel Prize in Physics last week – but their discovery could now be disrupting the behaviour of insects and therefore the food-chain, a new study has revealed.
The scientists who invented blue LEDs in the 1990s played a crucial role in the development of today’s bright white LED lighting, which is more energy-efficient than traditional incandescent bulbs. White LEDs are now being used to replace sodium vapour lights, which are commonly used in street lighting
However, researchers at New Zealand-based institute Scion have found that white LED light bulbs attract 48% more insects than sodium vapour lights. This potentially disrupts the food chain by causing flies to be thrown off their usual path and into the jaws of predators, and also has implications for the spread of pests if LEDs are installed in ports or on ships.
Insects are attracted to white and yellow light, but evidence suggests they are even more attracted to the short wavelength blue light generated by all LEDs. The study could have major implications as energy efficient LEDs are quickly replacing sodium lamps on streets across the globe.
“Insects have specific photo-receptors for blue light. Thus large-scale adoption of white LED lighting is likely to increase the impacts of night-time lighting on all species sensitive to short wavelength blue light.”
Stephen Pawson, Scion
Stephen Pawson, an entomologist at Scion, told Smithsonian magazine: “The main driver of the ecological impacts that result from a shift to LED lighting will be the increase in emissions of short wavelength ‘blue’ light.
“The behavior of many animals is influenced by light in the blue portion of the spectrum. Insects have specific photo-receptors for blue light. Thus large-scale adoption of white LED lighting is likely to increase the impacts of night-time lighting on all species sensitive to short wavelength blue light.”
Industrial white LEDs actually start life as a blue LED, which is covered with a phosphor coating designed to absorb some short-wavelength blue light and re-emit it as longer wavelengths. The combination of short and long wavelengths makes the light appear white to human eyes. According to the Smithsonian, the use of energy-efficient LED lighting has also been implicated in the rise of light pollution.
In the Scion study, scientists Stephen Pawson and Martin Bader, set out the LEDs and sodium lamps in a field at night next to sheets of a sticky material designed to trap any insects that came near. On average, the white LEDs attracted 48% more flying invertebrates than the sodium lamps. Overall, the researchers caught and labelled more than 20,000 insects, with moths and flies the most common groups.
Six different types of white LED were tested, each of which emitted a different amount of blue light. However, the number of insects trapped remained the same as each LED “still emitted enough blue light to have an effect,” said Pawson.
The team is now looking at implementing light filters to see if removing more of the blue wavelengths makes the lights less attractive to insects.
The inventors of the blue LEDs were last week awarded the Nobel Prize for physics. Japanese scientists Isamu Akasaki and Hiroshi Amano and US scientist Shuji Nakamura devised the technology in the 1990s.
LEDs have become the most energy-efficient light source, typically using around 90% less energy than incandescent bulbs and lasting for 100,000 hours compared with 1,000 hours for tungsten filament light bulbs.
According to a report in the Mail Online, when Nakamura invented the technology in 1993, the company he worked for at the time, Nichia Corporation, awarded him the equivalent of just £125, despite the idea being worth a potential £50bn by 2020, according to estimates.
Nakamura subsequently quit the firm and moved to the US in 2000, before counter-suing in 2001 after Nichia attempted to sue him for infringing trade secrets. He was ultimately awarded £5.04m for the idea, reportedly the largest payout ever made to an employee for an invention.
