Photoreceptor cells in insects enable them to perceive different wavelengths of light such as infrared and ultraviolet. Thanks to these abilities, they use light for purposes such as determining direction, finding food, and protecting themselves from dangers.
Thanks to these wavelengths, which they can perceive differently from humans, they determine their direction at night. Artificial lights such as street lamps cause insects to be unable to use their abilities, and insects become unable to navigate in the dark.
Apart from photoreceptor cells and wavelength of light, another possible reason is thought to be the inability of insects to use sunlight and moonlight.
Insects, which determine their direction by using these natural lights, lose this ability because the distance between them and the light source and the angle of incidence of the light change significantly due to artificial lights.
Insects receive light from natural light sources at a fixed angle, but since artificial lights scatter light in all directions, this causes insects to maintain a fixed angle. As they fly, their angles with the light source get narrower and they start to revolve around artificial light sources.
To reduce the effects of this situation, which negatively affects insects, you can use yellow tones instead of blue light.
Because blue light confuses insects more, while yellow light has less effect. It is also a better option for humans because yellow lights are more economical. According to a study using 8887 insects and spiders, incandescents attract insects the most.
Fluorescent lamp, halogen lamp, LED lamp with cold color temperature and yellow lamp follow incandescent respectively. The lamp type that attracts insects the least is LEDs. By using a yellow LED light in your home, you can get rid of the insect infestation and you will be doing them a favor.
“Phototaxy”, which is defined as the positive or negative reaction of living things to light, may also be one of the answers to this question.
“Photo” means “light” in Greek, and “tax, taxo” means “arrangement”. Insects with positive phototaxis, such as moths and flies, turn to the source when they see a light source, while insects with negative phototaxis, such as cockroaches, tend to flee when they see light.
Most naturally occurring cyanobacteria do positive phototaxis because light is required for photosynthesis. Insects develop positive or negative phototaxis due to evolutionary reasons. Apart from phototaxy, there are also taxi methods such as chemotaxis, hydrotaxy, gravitaxy, aerotaxy, and electrotaxis.
Insects can sometimes land on your clothes for a similar reason.
Some flowers that insects see as their “main food” reflect ultraviolet rays, which attracts them. Due to the rays reflected by some colors, they can be placed on you as they perceive the patterns on your clothes as if they are flowers.
Now you know the possible causes when you see a swarm of insects swarming into the light. Stay with science.
Sources: TUBITAK, Science in 2 Minutes (NTV), IFL Science
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