A new study suggests that flying insects, such as moths and dragonflies, are not actually attracted to bright lights, as many scientists and poets have long assumed. Instead, researchers believe that artificial lights turned on at night could disrupt the innate navigation system of flying insects, causing them to flutter in confusion around lamps, streetlights, and other artificial lights.
According to the study published in the journal Nature Communications, insects do not fly directly towards the light source but actually “tilt their upper part towards the light,” leading to mid-flight confusion rather than attraction.
Researchers attached small sensors to moths and dragonflies in a lab to film “motion capture” videos of the flight, similar to what filmmakers do when they attach sensors to actors’ bodies to track their movements. They also used high-resolution cameras to film insects hovering around lights at a field site in Costa Rica.
The study found that the insects’ flight was less disturbed by lights shining directly downward, but they experienced more confusion and disorientation when faced with lights shining slightly upward, such as spotlights.
“For millions of years, insects oriented themselves by sensing that the sky is light and the ground is dark,” said Avalon Owens, a Harvard entomologist who was not involved in the study. The study suggests that the introduction of artificial lights by humans has disrupted the natural navigation system of flying insects.
The findings could have implications for understanding the impact of artificial lights on insect behavior and ecosystems and may lead to further research on how to minimize the negative effects of human-made lighting on the natural world.