Research proves that light with less blue wavelengths keep bugs away.
The swarms of insects that plague light bulbs at night could be about to become a thing of the past. Scientists have invented a bulb that emits less blue and green wavelengths, which they claim is 20 per cent less appealing to moths and other bugs. The technology could also save lives in the tropical regions of the world, where insects carry a multitude of potentially fatal diseases.
Light emitted by conventional bulbs – particularly the blue wavelengths of LED bulbs – is attractive to a range of insects, drawing them out from the night and straight to people’s homes. The problem with this is that insects such as mosquitoes, sand flies and ‘kissing bugs’ that fly towards the light, increase the risk of catching vector-borne diseases.
Six million people worldwide, mostly in Latin America, are infected with Chagas disease, which is transmitted by ‘kissing bugs’ that are attracted to lights. Sand flies infect people with a protozoan parasite responsible for 20,000 deaths annually, while mosquitoes, which are also drawn to the light, carry malaria which kills more than 600,000 people a year. While you may imagine that the brightness of a light bulb may dictate how many insects are drawn towards it, scientists from the University of Southern California say it’s the colour of the light that matters most.
Travis Longcore, associate professor of spatial sciences at the university, said, “Future LED bulb designs could be customised to be less attractive to specific insect species”. All insects are attracted to ‘white’ light, which is a combination of all colours, but different insects are sensitive to particular combinations of these wavelengths. For example, blue, violet, and ultraviolet wavelengths are especially attractive to moths and some other insect groups, so these wavelengths were turned down in experimental light bulb. However, the light it emitted still appeared white to humans.
Professor Longcore led a team, with help from Philips Research in the Netherlands, with the aim of reducing the number of insects an LED bulb can attract while still maintaining white light for indoor use. Dr André Barroso, a senior scientist at Philips said, “For the purpose of this study, we created unique and one-off LED lamp designs that can be customised to emit different colour wavelengths to reduce the attraction of insects”.
This is where lighting meets health and well-being. The bulbs were tested against off-the-shelf commercial LED bulbs, compact fluorescent bulbs and a control with no bulb. Professor Longcore’s research team fixed each bulb over traps in several locations in California – two in the Santa Monica Mountains to represent rural locations and one in the city of Los Angeles.
In just over a month, they collected 5,579 insects in the traps, it was reported in the journal Philosophical Transactions B. The order Diptera, which mosquitoes belong to, represented almost seven in every 10 insects caught. They found that despite the customised bulbs being brighter than the LED bulbs, they attracted 20 per cent fewer insects. He said, “The research provides proof in concept that LED lamps can be customised to avoid specific areas of the spectrum that could have adverse environmental consequences, while still providing light for indoor use”.
For places in the world where glass windows and screens are uncommon, reducing insect attraction to indoor lights is a big deal. Future research is needed into the light attraction of individual vector species and with the current configurations in the tropics, but the current results indicate a viable path forward.
Source: Daily Mail, UK