Washington: Researchers are developing new kind of light bulbs that are less attractive to specific insect species, including disease-spreading mosquitoes.
Many insect species are attracted to light, which means that the type of bulb you use can actually 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 a bug that is attracted to lights.
Sand flies, also attracted to light, infect people with a protozoan parasite responsible for 20,000 deaths annually. Mosquitoes, which carry malaria, are documented to be attracted to light.
A new study by the University of Southern California researchers found that what matters most is not just how bright the bulb is, but what colour wavelengths it gives off.
Future LED bulb designs could be customised to be less attractive to specific insect species, said Travis Longcore, associate professor of spatial sciences at the USC Dornsife College of Letters, Arts and Sciences.
The white light given off by bulbs is attractive to all insects, but 'white' is not actually a colour - it's a combination of light of all colours.
Different insects are sensitive to particular combinations of these wavelengths.
Blue, violet and ultraviolet wavelengths are especially attractive to moths and many other insect groups; additionally, they are also disruptive to human circadian rhythms, meaning they can actually interfere with sleep patterns.
Longcore and a team of his former students from University of California, Los Angeles tested to see if they could mitigate these effects as part of a research project with Philips Research in the Netherlands.
Their primary goal was reducing the number of insects an LED bulb can attract while still maintaining white light for indoor use.
Collaborator Andre Barroso, a senior scientist at Philips, provided the bulbs.
"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," Barroso said.
Longcore and his team fixed each bulb over soapy pan traps in several Los Angeles County sites: two locations in the Santa Monica Mountains represented rural conditions, while UCLA's Mildred E Mathias Botanical Garden stood in as an urban test site.
In just over a month, they collected 5,579 insects in the traps. The order Diptera, which mosquitoes belong to, represented 67.5 per cent of all the insects caught.
The housing of the customised lamps actually allowed more light through than the housing for the commercial, off-the-shelf LED bulbs. But despite the customised bulbs being brighter, they attracted about 20 per cent fewer insects, researchers said.