Get To Know: How Do Flies Reproduce?

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Flies are one of the most pervasive pests in the world. But despite their widespread prevalence, not much is known about them. 

Consequently, get to know the flies better by learning everything there is to know about How do flies reproduce!

How do flies reproduce?

When it comes to how do flies reproduce, the process is actually quite complex.

Males and females of most fly species mate while the male grasps the female in flight. The mating process generally occurs on a solid surface, such as the ground or a wall.

The sperm received from male flies during their only copulation moves into a storage area located in the female fly’s reproductive system called the spermatheca.

From there, it can be used at any time to fertilize an egg. This is the reason the female flies typically only mate once during their lifetime and lay eggs multiple times throughout their lifetime.

How do flies reproduce

Following the mating of the flies, the females eventually lay eggs.

The eggs hatch into the larva, which then turns into a pupa. After a certain amount of time, the pupa will become an adult fly.

Lets me explain these stages in-depth in the following section.

The Life cycle of a fly

fly puparium

Flies go through four life cycle stages: Egg, Larva, Pupae, and Adult.

Female flies lay their eggs in different areas, depending on the species of fly. The eggs are laid in batches and generally hatch within a few days.

The eggs will hatch into larvae.

Larvae live off the organic matter until they undergo a series of molts before pupating into an adult fly.

A Fly’s lifespan is usually around 15-30 days but can vary depending on the environment and other factors such as their species.

Fly eggs

After mating, the female fly will lay her eggs.

Flies are attracted to organic matter, which is why they lay their eggs on rotting food, garbage, carrion, and animal or human feces. Once the eggs hatch, the baby flies will feed off of the decaying organic matter until they are ready to fly away and start the process over again.

Wondering How many eggs can flies lay? Well, the female fly can lay around 500 eggs in her lifetime, in batches of between 75 and 150, after attaining maturity, which typically occurs around the 12th day.

Fly larvae

Fly larvae are the immature stage of the fly. They are worm-like in shape and pale in color. They are very beneficial for breaking down decaying matter and can be found near their food source. Larvae feed best when they are close to animal corpses, manure, and garbage.

Fly pupae

When a fly’s larval stage is complete, the pupae develop a cocoon-like shell. During this time, the pupae grow their wings, antennas, and legs. In addition, the pupae also undergo significant changes in color and morphology.

After the pupae stage, flies are in their adult form. They mate, and the female fly eventually lays eggs. The eggs hatch into larvae, which go through more stages before becoming pupae.

What Areas of Buildings Do Flies Lay Their Eggs In?

Now that you are aware of the various lifecycle stages let’s investigate the typical breeding locations of different flies inside buildings.

House Flies

House flies are attracted to moist, decaying matter and can be found near homes, around trash, feces, and grass and garden waste.

Flies lay eggs near food sources, and the eggs hatch into larva that feeds on the rotting material. The larva pupate and emerge as adults, ready to mate and lay eggs.

Drain Flies

Drain flies are attracted to moist and dark areas, which is why they are often found near drains, garbage disposal, pipes, and other humid places.

Fruit Flies

Fruit flies can be a nuisance in homes and businesses. They are attracted to overripe fruits and vegetables, as well as garbage cans. They can also start infestations in other areas of the home.

What Outdoor Locations Do Flies Use to Lay Their Eggs?

fruit flies

Horse Flies

Horse flies are insects that typically prefer the outdoors. They bite dark-colored animals, such as horses, to get blood. They lay their eggs in manure, and the larvae live in the manure until they become adults.

Stable flies

Regardless of whether it’s animal waste or rotting vegetation, stable flies deposit their eggs in these elements. As stable female flies need blood to breed, they bite; hence locations with livestock, such as cattle, horses, or other farm animals, tend to have this type of fly.

Cluster flies

Cluster flies are pests that can enter buildings through cracks and openings and lay their eggs on surfaces. Once the eggs hatch, the baby flies will feed and reproduce on the surface before flying away. The cycle will then start over again as more cluster flies enter the building.

How Long Do Flies Live?

While the lifespan varies with different species, the typical duration is found to be between 15 and 25 days. During this time, they go through a complete life cycle, from egg to adult.

Getting Rid of Flies

flies fruit eggs kill

In order to get rid of flies, it is important to eliminate their food sources. This can be done by cleaning up any messes or spills and ensuring that there is no garbage or rotting food lying around.

Furthermore, make sure to sweep and mop your floors regularly and take out your trash frequently.

You can also use fly traps or insecticides to kill the flies. Another common method is using screens. Screens can be placed on doors and windows to keep the flies out.


In conclusion, as you now know, flies undergo a life cycle that includes four stages – egg, larva, pupae, and adult fly. During the pupae stage, the fly will transform from its previous form into its adult form.

After this process is complete, the adult fly will mate and lay eggs to start the process over again.

They typically live between 15-30 days and can multiply in great numbers!

Consequently, flies can be difficult to get rid of. A professional exterminator may be necessary, and fly control is a long-term solution that requires patience and diligence.

About the author

A biotechnologist by profession and a passionate pest researcher. I have been one of those people who used to run away from cockroaches and rats due to their pesky features, but then we all get that turn in life when we have to face something.