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What Are Flies Attracted To?

Last Updated: 27.11.22


If you want to find out what attracts different fly species to your house, you can check it out here. Depending on their feeding and breeding process, flies could be attracted to ripe fruits, clogged drains or flower bouquets. And as we all know, most flies are attracted by light.



You don’t have to work as a professional pest controller to know that flies are attracted to light. It is a common thing to see insects wildly flying around lighting objects and street lamps once it gets dark outside.


Why are flies attracted to light?

It has been noticed flies are more attracted by LEDs rather than fluorescent lamps and it is because of the way LEDs emit light. LEDs produce UV-A and the flies’ eyes are more sensitive to light at that wavelength.

They might think of a light fixture the same way we think of a lighthouse. When they sense a dangerous situation, flies instinctively go toward light sources, which are usually placed on higher ground than the precarious environment they are presently in.

Lights can be for some insects a common safety signal, just like air bubbles might help other creatures as they show the way to the surface.



Scientific debate

Scientists are still trying to find out why a fly will keep on hovering around an artificial source of light even when a natural light source is available. Part of the scientists say the flies are not attracted to the light itself, but the dark area surrounding it.

Another cause might be represented by the insect’s eyes, which generally have multiple lenses so the fly has a hard time trying to adjust from light to dark. This makes it vulnerable to natural predators while it is night-blind. So the flies choose to stay in the light as it is safer than flying away and not being able to see obstacles and threats.


Using the light to navigate

There is yet another theory trying to explain why flies are attracted to light. They could use it as a navigation landmark. For example, if a fly is going north, it should be able to choose the direction by keeping a natural light source (the moon or the sun) on its right side. The method is efficient if the light source is both constant and at a distance.

If a fly sees a lightbulb placed on the porch, it will become confused by it. This is the reason why moths frequently encircle a light source. It instinctively tries to keep the source of the light on a certain side of its body while flying toward its destination.


Only adult flies are attracted to light

In the first part of their life, during the larval and pupal stage, flies have negative phototaxis so they are not attracted to light. They are not fully developed and generally more vulnerable so, in order to survive, they remain in the breeding site. 

Once they go through the molting parts of their development, they get stronger and become good fliers. This is when they turn into insects with positive phototaxis which are naturally attracted to light.


Fly killers using light

A better understanding of the flies’ natural attraction to light might help us to develop more efficient insect light traps and adjust fly control solutions. This could impact the food industry as it would be easier to control outbreaks of diseases carried by flies such as salmonellosis and dysentery. 

The main advantage of fly traps using LEDs is that there are no pesticides needed and they can be used both indoors and outdoors as long as the environment is dry and there is an available outlet. 



Slow or clogged drains

The slimy matter found in drains is the favorite feeding and breeding site for drain flies. In their natural habitat, drain flies gather, mate, and lay eggs in moist soil or standing waters such as lakes or ponds. If you have a slow drain, the gunk that accumulates in it will keep the drain flies coming and provide them with a safe place to feed and breed.


Infestation signs

The most obvious signs of their presence are the adult flies. You might find them in the bathroom or in the kitchen, resting on the room’s walls close to the clogged drain. Once they found a good feeding and breeding place, they come into your house in large numbers.

Besides being annoying, they might even plug the pipes if they live and develop there for a long time. They will take bacteria from the clogged drain and carry it on your food. However, drain flies don’t transmit any harmful bacteria to humans. 


How to keep them away

In general, the most efficient method is to get rid of their feeding and breeding site, which is the slime inside the drains. After removing it, give that area a thorough cleaning so the flies don’t come back. Using a regular drain cleaner might not produce the best results so you should try something more efficient. 

After cleaning the drains, the infestation issue is almost resolved since the adults are still flying around the room. They will live for a maximum of 3 weeks and after that, you will no longer have to worry about drain flies since they can’t find a place to lay the eggs.


Fruit and alcohol

Ripe fruit, the ferment made by the decaying process, and alcohol represent the main course for fruit flies. They can feel almost any fermenting food from a few miles away so don’t forget to put foodstuff back into the fridge.

Since fruit flies don’t have teeth or mouthpieces to bite, they usually feed on liquid food. Even an uncleaned kitchen counter or a stain of wine that hasn’t been cleaned well will make them come to your house. Similar to drain flies, they could feed on the organic matter accumulated in drains. Also, they could be looking for a bouquet of fading flowers as adult fruit flies could eat nectar.



How to avoid a fruit fly infestation

First of all, make sure you don’t leave food on the kitchen table, especially if you are going out of town for a few days. To keep the drains clean, use regularly drain cleaner so they don’t have a breeding place.

Also, you could use plants such as basil or mint to keep them away. You can get these from almost any store and basil has anti-viral and anti-bacterial properties. Not only it will keep flies away, but it will help to create a healthy climate inside your house.

In case you don’t like the scent of basil, there are other options available. Plants such as tansy and bay leaf can be used as fly repellents. You can get more scented plants and place them around your house and they will create a beautiful natural scent. 


Dark and moving animals

If you are spending time outdoors you should be aware of horse flies. They usually live in wooded areas or close to animal farms where they can feed on larger animals. However, you can see them in urban zones close to waters such as lakes or ponds where they usually breed. 

Since they are usually feeding off horses, avoid wearing dark clothing as they might consider you as their next meal. Not all horse flies could bite you as only the females have mouthparts powerful enough to bite through skin. 

The bite is quite painful and usually, they don’t stop biting until they get enough blood or you kill them. They even have a chemical substance that prevents the blood from clotting so they keep on feeding. If you want to spend time outdoor carefree, wear light colors and avoid cosmetic products with a strong scent.


A nice shelter

If most of the fly species don’t survive the winter period, the cluster fly has the capacity to get through the cold season. Despite the fact that they only live for 30 to 50 days, the cold temperatures slow their activity so they could survive if they find a place to hibernate.

At the end of September, these flies are looking for appropriate shelter. They will gather around windows or doors as light attracts them and they will look for a way to enter the house. Once inside, they will huddle up inside a wall crevice or up into the attic and they will live there until the beginning of spring.



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