There is no scientific reason why ants would be attracted to light. Light does not have much of a benefit to ants. However, flying ants have been observed to have some attraction to light sometimes.
Some species, such as army ants, are completely blind, and the presence of a light source would not influence their movement patterns or behavior at all.
But the ants that are often observed sticking around light sources are the flying ants. Flying ants, which are also called alates, are ants that are ready to mate and reproduce. Usually, the wings grow during the breeding season and are shed soon after reproduction. As such, flying ants are made up of the queen ants and the male reproductive ants.
The main goals of flying ants are to reproduce and establish new colonies. However, none of these activities requires light as a prerequisite. So, it is challenging to establish if ants are phototactic.
Do ants have Phototaxis (The Attraction to Light)?
Taxis is a behavioral response of an organism to an external stimulus. Phototaxis, therefore, is the behavioral response of organisms towards light. Organisms that are attracted to light are said to be positively phototactic, and those that are repelled by light are negatively phototactic.
There are animals, such as moths, flies, and grasshoppers, that have positive phototaxis. Others like cockroaches prefer to be as far away from light as possible, and that is why you will find them hidden away in cupboards and in the darkest creases of furniture.
Ants are neither entirely positively phototactic nor negatively phototactic.
The majority are not affected by light or darkness. Their preference to build nests in hard-to-find places such as holes, under sinks, and near pipelines has more to do with remaining undetected than being in the presence or absence of light.
How Do Different Ant Species React To Light?
Researchers have shown that ants’ response to light is sometimes determined by underlying factors, such as interior and surface temperatures.
1. Redwood Ants
An experiment done on the Formica polyctena species, also known as Redwood ants, revealed that their phototaxis response changes from positive to negative based on the prevailing climatic seasons.
During summer, the ants would avoid direct sunlight and opt to stay in shaded areas. However, during spring, the Red Wood ants would prefer to bask in direct sunlight. Even when moved to the shaded areas, these ants would crawl back to the sunlight.
According to the researchers, this switch would occur when the temperature of the sun-exposed nest surface exceeded the lethal temperature for Red Wood ants, especially during summer.
2. Flying Ants
The type of ants that is known to show positive phototaxis are flying ants. It is important to note that these are not a separate species of ants. Instead, they are male and female ants that are sexually mature. Like many other insects, flying ants are positively phototactic.
If the swarm happens during the night, you will likely see the insects flying around a streetlight or your bulbs at home. The light that is emitted from your windows when it’s dark will also draw them in. During the day, you will notice the flying ants crawling from the inside of your windows as they are trying to reach the sunlight outside.
All in all, the majority of ants species prefer to stay in the dark than be exposed to direct sunlight. Most of the time, they only go out to the light when they need it, like in the case of the Red Wood ants or when looking for food and water.
Why Are Flying Ants Attracted To Light?
Flying ants are ants on the move to find a place to settle and bring up a new colony. There is not a single scientific reason to explain why these ants are attracted to light. Thus, there are a few theories that attempt to explain this attraction, as discussed below:
This theory suggests that flying ants follow light sources to help find their way around. How this works is that they base their radar on the source of light to determine the direction they are moving in.
For instance, if they are moving North, this source of light will act as their compass. The best light sources for navigational purposes are the sun and moon because they are constant and at a distance.
When this fly encounters an incandescent porch light or a bulb, confusion arises. This is because even though the source is constant, it is too close and, therefore, impossible to use as a navigational tool. Therefore, the fly will keep circling the source as it tries to keep it on one side of its body as it continues navigating its route.
Generally, when insects are in doubt and feel unsafe, they tend to fly towards the one thing that seems sure and safe. In many cases, this refuge is light – it is considered an emergency beacon. Furthermore, the light source tends to be on a higher altitude than the dangerous ground they are trying to escape.
Why Do Flying Insects Like Led Lights?
Research has found that insects are more attracted to LED lights than other forms of artificial light. The reason behind this unique attraction is that LED lights produce UV-A light. Insects such as flying ants are more sensitive to this light compared to others.
Flies and other insects are most sensitive to light at the wavelength produced by LED bulbs. In other words, the wavelength of light that is outside the visible light range is more attractive to insects than the normal light.
Ants are not particularly attracted to light. They are neither positively phototactic nor negatively phototactic. Their response to light is mostly conditional. There are times it is prudent to follow light, for instance, during summer. And other times, they actively run away from it.
Flying ants are the type of ants that show positive phototaxis. They are attracted to light for the same reasons that every other insect is attracted to light: safety and navigation.