Why are insects attracted to light

If you've ever observed a street light at night or turn on your porch light during the dark, what you'll probably notice is some bunch of insects flying and swimming around the light source, and the  most intriguing part of it is that they just keep on making endless circles around the light. These insects often ranges from small beetles to bugs or even moths.  

So why are insects attracted to light an why do they just keep circling around and around like that. Let find out.

It a good thing to know that insects that are naturally drawn to light are know as positively phototactic. 

The difference between insects attracted to light and those that are not is a phenomenon known as phototaxis. Certain insects, such as cockroaches or earthworms, have negative phototaxis, meaning they are repelled by exposure to light. Moths, flies, and many other flying insects have positive phototaxis, meaning they are naturally attracted to it.

It turns out that there is specifically no single explanation given by scientists on this behavior though, but there are several theories that suggest possible explanations as to why insects are attracted to lights. These theories suggest that electric lights, fires, and other glowing things might confuse the natural instinct of these insects. These natural instincts can be connected to their:

- Short term protection: 

- long distance navigation

- source of food

Short term protection:

Some insects do see light as a safety signal or an emergency beacon. When in doubt about their current environment, they fly straight to the light source for safety. Light can also be seen as a sign of an unobstructed path, which is a good thing if they're trying to escape a predator, or just to get to point B. 

Long distance navigation:

One of the theories behind these behaviors of getting attracted to light is that some insects use the moon to navigate at night. These kind of insects species tend to be nocturnal and many are migratory. So in order to stay on track while travelling long distances, they want to stay at a specific angle with respect to the moon. So it obvious that these insects possibly mistake any point of light they find in the dark for the moon. This can also explains why certain insects tend to fly in wild circles around the light; once they reach the glowing objects they thinks it the moon, they keep drastically changing their angles to the light source which ends up throwing them for a loop(literally).

Source of food:

Another thing to consider is that many insects are good in detecting ultraviolet(UV) light, flowers for example do reflects UV light  attracting some flying insects like bees and butterflies. Bees use the flower nectar and pollen as source of food. So positively phototactic insects might aim for your lamp or campfire  because they instinctively  thinks it's something they want, like a source of food.

So the next time you see an insects flying into a light source, keep in mind that not even entomologist are quite sure why it doing that. Maybe with some more research, it'll be figured  out.