An unexpected benefit of LEDs

However, new research undertaken by the University of Bristol has revealed a beneficial side-effect of LEDs that is not so well-known. A study which investigated how insects responded to different sorts of light has shown that LEDs attract around a quarter of the number of insects compared to traditional light sources.

The university is uncertain as to the reason for this, but one theory is that LEDs only emit tiny amounts of heat, whereas incandescent lights turn most of the electricity they consume into heat, with only a small amount emitted as the light we actually want. The significance of this? Some insects use thermal cues to find warm blooded hosts at night, and therefore are potentially more attracted to traditional forms of lighting such as tungsten.

In addition, the study also showed that the difference in attraction was particularly acute in biting insects. In the UK this discovery means we can reduce the chances of irritating uninvited guests turning up at our next barbecue.

However, apply the results of these findings to places like Africa, where people spend a greater amount of time outside and where, more importantly, the insects pose a much greater risk to peoples’ health – disease carrying mosquitoes for example – and you can see the potential impact of these findings.

The study successfully identified 4,000 different types of insects using customised traps at 18 field test sites across the south-west of England. Notably, for the biting insects identified (Culicoides), 80% were attracted to the filament lamp, 15% to the compact fluorescent but only two to three percent to each of the two LED lamps. When you consider that the number of malaria deaths in 2015 was more than 400,000, the significance of these numbers is obvious.

Dr Andy Wakefield, who led the research team, said: “We were surprised by the number of biting flies drawn to the traditional tungsten lights. We do not 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.”