Why are there always insects under the streetlights? The reason has been found!

Mondo Health Updated on 2024-03-07

As the temperature rises, everything recovers, and the insects that have been silent for a winter begin to wake up gradually, and the earth regains its vitality.

At night, the lights of the city are like a lighthouse in the stars, attracting swarms of insects. They dance around the street lamps like enchanted elves, unaware of the scientific mysteries behind the light. Insects are attracted to light, a phenomenon that is commonplace in nature, but in human cities, this instinctive reaction often leads to their disorientation.

Insects respond to light in a variety of ways, just as insects at night and at day have different patterns of activity. Nocturnal insects, such as noctuidae and moths, exhibit positive phototaxis, and they are attracted to light, like travelers guided by moonlight. This behavior may stem from their navigation system, which is accustomed to using natural light sources such as the moon and stars to locate their position. Daytime insects such as butterflies and aphids, on the other hand, exhibit negative phototaxis, avoiding strong sunlight and looking for shade. This different response to light is a survival strategy for insects to adapt to their environment.

Daytime insects use light to find food and habitat, just as navigators navigate through the stars, while nocturnal insects choose to move in the dark to avoid being targeted by predators. However, when night falls, the appearance of artificial light sources is like interfering with the built-in compass of insects, making them unable to discern the direction, constantly approaching the light source, and finally circling around the street lamp, unable to extricate themselves.

The phototaxis behavior of these insects is not just a simple response to light, but is closely related to their survival strategy. This behavior of theirs is both an adaptation to the environment and a misdirection in the human environment.

During the day, sunlight is the compass of the insect world. Butterflies and bees rely on light to guide them through the flowers, looking for food and companions. On their retina, each beam of light is a guide to life. When night falls, these diurnal insects choose to hide to avoid becoming prey to nocturnal predators. At the same time, nocturnal insects such as nocturnal moths and moths begin their activities. For them, darkness is the best safe haven, and light is a potential red flag.

In the world of insects, the brightest objects in the sky, the sun and the moon, are their natural navigation systems. Just as ancient navigators relied on the stars for positioning, insects also used the positions of these celestial bodies to determine the direction of flight. Their flight path is a straight line that maintains an angle to a point of light in the sky. This way of navigating, simple and effective, is the result of hundreds of millions of years of evolution.

Human urbanization has burdened these eon-billion-year-old experiences. The lights of street lamps and billboards, like newly rising false stars in the sky, disrupt the insect's navigation system.

When night falls, the streetlights become their new moon, their flight paths distorted, and their originally straight routes become endless spirals.

Instinctively driven, they try to fly at a fixed angle to these artificial light sources, just as they once did with the moon. However, due to the varying distances of light sources, this behavior causes them to spin and approach endlessly, until they hit the object where the light source is located.

In addition to the confusion of the navigation system, there are many reasons why insects are attracted to street lights. Some insects may mistake the spot under a streetlamp for an open flower, and their instinct drives them to fly to the light source in search of possible food**. Other insects may perceive a bright place as a sign of safety, especially when predators are present at night, and the light becomes a refuge from danger.

There are also insects, perhaps simply out of curiosity or playfulness, attracted by this unusual light. Whatever the reason, street lights have become an irresistible feature for insects in their nocturnal activities.

These little beings, who were supposed to soar freely in the brilliance of nature, were lost in the light pollution of human beings. Light pollution may not have much impact on human life, but for insects, it is a seismic change.

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