During the summer months, insects can often be seen flying around the artificial lights, which actually kill many of these small creatures such as moths and mosquitoes.
Avalon Owens of Harvard University says this “blunt rotation” can distract insects from goals like eating, mating and reproduction. Artificial lighting may contribute to the decline of insect populations around the world.
Why are insects attracted to artificial lighting?
There are many theories about this behavior, including that insects use the moon for navigation and artificial lighting is similar to the moon. Insects may try to escape towards the light or try to find darkness.
Testing specific hypotheses is difficult due to the difficulty of observing insects in flight. But new technologies may finally provide better answers.
In a paper published in the journal bioRxiv and not yet peer-reviewed, Yash Sundi, a researcher at the University of Florida who studies moths and sensory systems, photographed moths, dragonflies and other animals with Samuel Fabian of Imperial College London and other researchers. insects with a high-speed camera. And they noticed something unexpected: moths and dragonflies kept their backs to the light as much as possible.
Based on these observations, the latest theory is that some insects fly towards the light to navigate. Where usually light means up and dark means down.
The researchers explained that the reason the insects gather around the lamps is not because they are “attracted” to the light, but simply because their navigational systems are being disturbed by our artificial lighting.
Sondha and colleagues’ experiment may explain why insects stay close to light sources when they get there, but not how some insects find light over long distances or why some get stuck while others don’t.
Entomologists already knew that insects could fly at the same level during the daytime thanks to orienting instincts, turning their backs to sunlight even during mid-air maneuvers. However, a new study has shown that they lack this ability in the presence of artificial light in the dark.
Through experimentation, the team noticed that the insects appeared to be less affected when flying under a light pointing straight down, as opposed to lights pointing up or set horizontally.
Szondi’s findings may support the idea that “excessive lighting” is harmful to insects and should be avoided. Owens said that if the light was placed face up on the ground, the insects would turn upside down and die when they approached a source of scorching light.
The finding aligns with researchers’ longstanding advice to reduce light pollution by using downlights that only illuminate nearby ground.
Sondi agreed, saying, “Don’t turn on the lights.” He also recommended using a light that is more red than blue, considering how the insects are visible, and turning off ambient lights whenever possible.
Source: Living Science