"Like the moth around the light", colloquially insects like flies and moths react to artificial light by flying towards the light source. But this is not the same for all light sources, and insect species, such as mosquitoes, also react differently.
Scientific studies on the subject of light and insects exist mainly in the field of outdoor lighting. They were done because of the negative effects street lights had on the insect population. The main reason for this was the widespread use of high-pressure mercury vapor lamps, which killed millions of nocturnal insects.
With the yellow high-pressure sodium vapor lamps, more economical and more insect-friendly light sources found their way into outdoor lighting. The new LED technology can further increase energy efficiency and insect friendliness.
The light spectrum is crucial
The explanation for the attractiveness of light lies, in addition to the brightness, primarily in the respective light spectrum of the light sources: The sensitivity of nocturnal insects to certain spectral ranges of light differs greatly from that of humans. In contrast to the human eye, many insect eyes are sensitive to ultraviolet radiation (UV) and shorter wavelengths in the violet, blue and green range.
In contrast, their sensitivity in the yellow, orange, and red wavelength range is lower than in humans. A lamp that shines more strongly in the long-wave range is, therefore, less perceptible to insects than, for example, a lamp with high light intensity in the short-wave spectrum.
LED light and insects
With LED technology, a light source was added a few years ago, which has now also been investigated about its effect on insects. More recent studies show warm white LEDs to be the most insect-friendly choice among common lighting technologies due to their light spectrum.
In the summer of 2013, Ledon commissioned the Innsbruck entomologist (insect researcher) and court expert for ecology and entomology Dr. DI Karel Cerny to carry out a comparison of the insect attack, especially for household lamps.
For this purpose, light traps were set up and measurements carried out over several weeks. Three retrofit lamps of different technology were examined, but with comparable lighting parameters such as warm white light color and brightness. The result of these investigations using an eco halogen lamp, a compact fluorescent lamp, and a Ledon LED lamp supports the previous results, according to which LED lamps with a warm white color temperature are the most insect-friendly choice.
"The preliminary investigations I carried out in 2013 showed that Ledon LED lamps, compared to the conventional light source technologies of the eco-halogen lamp and compact fluorescent lamp, attract fewer insects and are therefore more environmentally friendly." DI Karel Cerny. Further scientific investigations are planned for 2014, which should serve to underpin the previous results.
Which light colors do mosquitoes dislike?
Special studies for the light sensitivity of a single species, such as that of mosquitoes, should only be carried out in laboratory conditions. As early as 2011, a study by Professor Dr. Gerhard Eisenbeis on the insect tolerance of LEDs compared to conventional light sources has similar results as the study for Ledon. During this work, the approach behavior of insects in Frankfurt am Main was observed. In the summer of 2011, six different light sources were equipped with insect traps, emptied daily and the yield counted. The best results (with the fewest attracted insects) were achieved with warm white LEDs, followed by cold white LEDs. Other lamps used in street lighting with a higher proportion of blue in the light attract significantly more insects. The study also found that mosquitoes were not attracted to the light sources.
Select light colors for insects
A warm white LED is therefore generally perceived less intensively by the insects. The light colors of incandescent lamps go in the same direction. You have to evaluate the mosquitoes differently. These are not attracted to the light but look for their prey using their sense of smell. They perceive breath and body odors so that they cannot be influenced by the color of the light. Special candles help here, as citronella candles can confuse the mosquito's sense of smell. So you won't be able to prevent stitches with the right light. Nevertheless, it is worth paying attention to a warm white light color in the garden, because at least it doesn't hum and hum in the wine glass.