Do insects gravitate towards light? Recent studies indicate it's due to disorientation, not an irresistible pull.

Do insects gravitate towards light? Recent studies indicate it’s due to disorientation, not an irresistible pull.

For years, scientists and poets have believed that flying insects were irresistibly attracted to bright lights, similar to moths drawn to a flame.

However, a recent study proposes that the situation may not be precisely as it seems.

Instead of being drawn to light, scientists theorize that artificial lights at night may disrupt flying insects’ natural navigation abilities, causing them to fly aimlessly around porch lights, street lamps, and other man-made sources of light.

According to Tyson Hedrick, a biologist at the University of North Carolina, Chapel Hill, who was not involved in the study, insects struggle with navigation because they rely on light as a guide to determine their orientation.

According to Sam Fabian, an entomologist from Imperial College London and co-author of a study published in Nature Communications on Tuesday, insects do not fly straight towards a light source. Instead, they tilt their backs towards the light.

This would be logical if the most powerful source of light came from the sky. However, with the existence of man-made lights, this leads to disorientation in the air rather than drawing attention.

In order to conduct the study, scientists affixed minuscule sensors to moths and dragonflies within a controlled environment in order to record “motion-capture” footage of their flight. This method is comparable to the way filmmakers attach sensors to actors in order to monitor their actions.

Additionally, they utilized high-quality cameras to capture footage of insects flying around lights in a field location in Costa Rica.

This enabled them to thoroughly observe the behavior of dragonflies as they continuously circled around sources of light, orienting themselves with their backs towards the beams. They also recorded instances of insects flipping upside down and frequently crashing to the ground when exposed to lights that shine directly upwards, resembling search lights.

The researchers discovered that bright lights shining directly downwards had the least impact on insect flight.

Until the invention of artificial lights, insects relied on their ability to perceive light and darkness in the sky and on the ground for millions of years, according to Avalon Owens, a Harvard entomologist who was not part of the study.

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Source: wral.com