Why Do Flies Head To The Lamp?

Why Do Flies Head To The Lamp?

I’m sure everyone who has seen the title has observed this situation. We don’t need to be an entomologist for that. But what’s wrong with the flies? Why do they keep beating the lamp without stopping?

Unfortunately, this story will not have a happy ending. A sad story awaits us!

First of all, we can safely say that there is not only one answer to this question. In this article, we will look for some answers by considering many hypotheses that try to explain the situation.

A Bug’s Rebellion to the Lamp: When the moon hits your eyes…

Like a big pizza pie, That’s more… “Who is the artist that insects listen to the most?” If you ask, the answer we give will probably be Dean Martin. But why? Some insects, such as moths, have developed a method for flying straight. This method is called transverse orientation. These insects move at certain angles by taking the moonlight as their reference, and thus they always fly straight.

Orientation of flies to the Moon

The Darkest Day in Insect History: The Invention of the Lamp

The day Thomas Edison invented the light bulb in 1879 was probably the brightest day for us humans. Now we could obtain the light of the Sun and the Moon whenever we wanted. However, this would lead to a disaster that no one could foresee. It was almost like a butterfly effect. That day is called the darkest day in history by all insects. The human being, who suddenly acquired artificial light, caused the insects, which had developed over thousands of years, to throw away their ability to find their way. There are now many light sources around us that shine like the moon. This, of course, causes confusion for insects, which can tell their direction by looking at the light.

Is Light the Only Reason?

No, the other important reason is temperature. If you’ve tried touching a working light bulb, you’ve probably noticed how hot it is. The electric current passing through the wire inside the bulbs causes this wire to overheat (approximately 3000 °C). Today, although not at such high temperatures, it is still at levels that can be considered hot. For insects that want to stay warm in cold weather, the bulb’s surroundings will be a very good choice.


Unfortunately, another unexpected danger awaits the flies, who say, Ooo, let’s go to that lamp so that we can warm up”.

The Trap That Fly Biology Can’t Resist: Electric Fly Killers

Light is very attractive to insects for the reasons we mentioned above. Among these lights, the favorite of the flies is the blue UV light. Realizing this, human beings used the flies’ tendency to this light to get rid of them. Most electric fly killers work with this blue UV light. Instinctively, the flies flying towards here are trapped and exposed to high electric currents. These devices are frequently used especially in factories or eating and drinking places that need to be more hygienic, and due to this tendency of insects, they become an insect graveyard in a short time.

Fly Killer

Other Possibilities

Besides these two main causes, there are several other hypotheses. For example, many moths feed on nectar from flowers that are known to reflect UV light. Some bulbs also emit small amounts of ultraviolet light, potentially causing hungry insects to mistake the bulb for a bloom.

Why Flies Head To Lamp

The other possibility is that the light gives confidence. Like many of us, insects feel less safe in the dark. Especially in the wild, light signals a way to escape from potential danger. When an insect sees the light, it can mean that the path has not been blocked by predators or obstacles. This may explain why insects fly toward light sources and unknowingly crash into light bulbs and lanterns.

The Killer of the Most Beautiful Emotions

There is also the other side of the coin. Some insects are conscious that other insects also turn to light. They probably won’t be alone when they get there. This festive environment is a great opportunity for mating insects to find potential partners. Our insects, which escape from the cold outside and travel to warm regions, can have a happy time with their mate as if they are on a honeymoon. On the other hand, there are predatory species who are aware of this situation. These hungry species know there are other drunken insects around the light. And they can fill their stomach by eating newly married couples.

But did you know that mosquitoes are the deadliest animals in the world? For more detailed information, you can read our article “The World’s Deadliest Animal: Mosquito”!

References and Further Reading

Quora. (2021, June 29). Why are insects attracted to light? Forbes. Retrieved December 8, 2021, from

Why are bugs attracted to light? Wonderopolis. (n.d.). Retrieved December 8, 2021, from

Why are insects attracted to light? – the rentokil blog. (n.d.). Retrieved December 8, 2021, from

Wikimedia Foundation. (2021, November 29). Transverse orientation . Wikipedia, the free encyclopedia. Retrieved December 8, 2021, from

Images not cited are used through Canva Pro with a royalty payment.

The proofreading has been done by Asu Pelin Akköse and Mete Esencan.

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Mete Esencan

Hello everyone! I'm Mete Esencan. I am a graduate student in the Department of Chemistry at METU. I was planning to establish a platform by combining the research knowledge I gained during my basic science education and the management experience I gained in the METU Chemistry Society, which I was in charge of for three years. For this purpose, in February of 2021, I took the first step and established the OkButWhy, a platform where we can write articles as if to chat about science, art and philosophy. I wish everyone a pleasant reading!

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