For decades, scientists have believed that insects were attracted to bright, artificial light. This has spurred the creation of countless “insect lights” designed to attract and kill bugs. But now, new research says it may not be insects’ attraction to light but confusion that causes their flight systems to become scrambled.
I previously discussed these findings when they appeared in a preprint server last year, but now the results have been peer-reviewed and published in Nature Communications to help document the findings.
The new study looks more deeply at the relationship between insects and lights. In it, the researchers detail their findings that insects do not appear to fly directly into a light source. Instead, they fly with their backs tilted toward the light.
This is likely because insects use light to tell them which way is up. However, when they see bright, artificial lights, it confuses their navigational systems, thus causing midair confusion. As such, the insect’s perceived attraction to light is actually them becoming confused by it and struggling to overcome that confusion.
To study this particular phenomenon, the researchers utilized a field site in Costa Rica and then used high-resolution cameras to film insects swirling around the lights placed there. This gave them an in-depth look at how dragonflies circle light sources endlessly, positioning themselves with their back toward the light.
Some insects, they documented, will even flip upside down, causing them to crash land in the present of lights that face upward. The researchers also studied how insects react to bright lights facing downward and found that they were disrupted the least when near those lights.
This new study greatly helps us to understand what many have long perceived as an insect’s attraction to light. For millions of years, insects have relied on light to tell them which way the sky is, orienting themselves with the light against their backs. But, in the presence of artificial light, all those years of training and evolution are thrown into disarray, causing the confusion that we so wrongly took for attraction.