One thing that many people have noticed about insects is that they seem to be attracted to light. Anyone that has sat around a fire outside or turned a light on in a dark room will have noticed that insects will often move towards the area of light. 

There are lots of different reasons that can explain why insects are attracted to the light, and we will explain them all for you in this article so you can finally find out why it happens. For those that are curious, there is no one reason that can explain this behaviour, as all insects are different, but we will list all of the main causes here.

There are many different theories, some proven, others not, that can explain the behaviour of insects, and it is really interesting to learn about. It is no secret that insects are attracted to light, but the burning question is often ‘why’? Well, in this article, you are going to find out.

What is Phototaxis?

Phototaxis is a concept that can explain why some insects are attracted to the light while others are not. There are certain insects, like cockroaches or earthworms, that have negative phototaxis, and this means that they are repelled by an exposure to light. On the other hand, there are insects like moths and flies that have positive phototaxis, and this means that they are naturally attracted to the light.

Why Are Insects Attracted To Light?

Insects are attracted by light so they can navigate, find food, be near heat, and avoid predators. There is something called phototaxis that explains how different insects will respond to light with motion. Some insects will be attracted to light, but there are also other insects that will avoid it. We will explain the different reasons why insects are attracted to light below.

Using Light to Navigate

One of the biggest reasons why insects will hang around by light is because they will use the light as their guide. There are lots of insects that use natural sources of light to guide them, and they can use sunlight or moonlight to do so. 

However, when it comes to artificial light, insects often become lost and easily confused as they have mistaken the source of light for the sun or the moon. So, instead of keeping a natural light source as their guide, they will try to keep the artificial source of light at a constant angle.

Due to the fact that artificial light will send beams in different directions, insects are not able to keep the light at the right angle, which leads to them circling around the light source. 

Light the Way

Another theory as to why insects are attracted to light is so it can light their path for them. Instead of flying around in the dark and trying to avoid things as they go, they will head for well-lit areas so they can see where they are going.

Finding Food

It is also possible that some insects are mistaking artificial lights for flowers, and this is why they head in that direction. There are some flowers that will reflect ultraviolet light. Artificial lights will also emit a small amount of ultraviolet light, and so some insects might be mistaking them for flowers, and head towards what they think is a source of food.

Source of Heat

Some insects will be attracted to light bulbs during the night as they give off heat. You might have noticed this occurring when it is dark and cold out.

Avoiding Predators

There are other insects that are attracted to light as in the wild, light can signal an escape from danger. When an insect sees light, it will tell them that their path is not blocked by a predator or another obstacle. This could explain why insects fly straight into sources of light.

Following the Crowd

A simpler reason why other insects are attracted to lights is because they know that other insects are doing the same thing. This is ideal for predators that are looking for a snack and insects that are looking for a mate, as they know exactly where they can find other insects.

Why Are Flies Attracted To Light?

As you now know, there is no one reason that can explain why insects are attracted to light, and there are many different reasons why this occurs. Some of the theories that can explain why flies, in particular, are attracted to light are:

  • They see light as an emergency beacon and a safety signal
  • They use light to help with their flight and navigation
  • They have a natural attraction to light known as phototaxis

Do Insects Associate Light With Safety?

This might not apply for all insects, but a light source can be interpreted as an emergency beacon that insects will head towards instinctively when in doubt. It is also helpful that light sources are usually high off the ground, away from more hazardous environments. 

Do Insects Use Light For Navigation?

Insects do use light for navigation purposes, and it can help them to know where they are going. If an insect is flying north, it will be able to find out the direction that it is travelling in by keeping a natural source of light, like the sun or moon, on its right side. Artificial lights can often confuse this process, which explains why many insects will circle around light bulbs.

Why Are Moths Attracted To Light?

Moths are attracted to light as they are nocturnal and they evolved to be able to use natural light sources for navigation. They will navigate by keeping themselves aligned at a certain angle relative to a natural light source.

Summary

There are lots of different reasons that can explain why insects are attracted to light, and it turns out that these insects were once very clever before artificial lights came along and confused them. Artificial lights confuse the navigation process and make things much more complicated for these insects.