Using LED lighting reduces the attraction of disease-carrying insects

Research funded by the Natural Environment Research Council (NERC) and Integral LED and conducted by a team from the School of Biological Sciences, revealed that domestic LED lights are much less attractive to nuisance insects such as biting midges than traditional filament lamps.

LED lighting is predicted to constitute 70% of the outdoor and residential lighting markets by 2020. But while the use of LEDs promotes energy and cost savings relative to traditional lighting technologies, little is known about the effects these broad-spectrum ‘white’ lights will have on wildlife, human health, animal welfare and disease transmission.

The work of the team highlighted the need for further research on other heat-seeking flies that transmit disease, including for example mosquitoes, which carry pathogens that cause damaging diseases such as malaria and Zika fever. As a result, Professor Gareth Jones has been awarded a 4-year Industrial CASE PhD studentship from NERC  with UK lighting manufacturer Integral LED as the industrial partner. Together the team will work on the attraction of mosquitoes to a range of lamp types, including LEDs, in Africa, starting in September 2018.

The original study was also funded by NERC and Integral LED. The field research was led by Dr Andy Wakefield in a project supervised by Prof Jones and Stephen Harris.

The team used customised traps at 18 field test sites across south-west England, illuminated by a series of LED, filament and fluorescent light sources, all commercially available ‘domestic’ lights. Over 4,000 insects, mainly aerial insects, were carefully identified.

The results showed that LEDs attracted four times fewer insects compared with the traditional incandescent lamps, and half as many as were attracted to a compact fluorescent lamp. Specifically, for biting flies (midges in the genus Culicoides, some species of which carry wildlife disease), 80 percent were attracted to the filament lamp, 15 percent to the compact fluorescent and only 2-3 percent to each of the two different LED lamps.

The LEDs attracted significantly fewer insects than other light sources, but there were no significant differences in attraction between the ‘cool-’ and ‘warm-white’ LEDs.

Dr Wakefield said “we were surprised by the number of biting flies drawn to the traditional tungsten lights. We don’t know why this is but we know that some insects use thermal cues to find warm-blooded hosts in the night, so perhaps they were attracted to the heat given off by the filament bulb.”

Co-sponsors of the study, Integral LED were instrumental in the commissioning of the project and provided technical and financial support.

The UK company’s Marketing Director Sanjiv Kotecha said: “As lighting manufacturers, we welcome that a link between LED lights and low attraction to insects has been proven. The energy saving advantages of solid-state lighting are well known, yet the benefits to well-being are only beginning to be revealed.”

The project showed that the use of LEDs has the potential to mitigate disturbances to wildlife and occurrences of insect-borne diseases relative to competing lighting technologies. But the team have also warned about the risks associated with broad-spectrum lighting and net increases in lighting resulting from reduced costs of LED technology, including the risk to wildlife.

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