Updated: June 1, 2023

Flies are a common sight in our environment. They can be found buzzing around our food, garbage, and even our homes. Their presence may be considered annoying, but it is important to understand their life cycle to better control their populations.

The Four Stages of a Fly’s Life Cycle

Flies undergo four stages in their life cycle, each with distinct characteristics and developmental changes. These stages include the egg, larva, pupa, and adult stages.

Egg Stage

The egg stage is the first stage of a fly’s life cycle. Eggs are usually laid in moist environments that provide adequate nutrients for the larvae to feed on once they hatch. Female flies lay their eggs on decaying organic matter, such as animal waste or rotting fruits and vegetables.

The number of eggs laid by a female fly varies depending on the species. A single female housefly can lay up to 500 eggs in her lifetime. The eggs hatch within a few hours to a few days, depending on environmental conditions.

Larva Stage

The second stage of a fly’s life cycle is the larva stage. Once the eggs hatch, the larvae emerge and begin feeding on the organic matter where they were laid. Larvae are commonly referred to as maggots and have cylindrical bodies that are legless and white.

The larva stage is marked by rapid growth and development as the maggots feed on the organic matter. The duration of this stage varies depending on environmental conditions, but it typically lasts for a few days to several weeks.

Pupa Stage

After the larva stage, flies enter the pupa stage. The pupa is an inactive stage where the maggot transforms into an adult fly. The pupa is enclosed within a protective casing called a puparium, which is made of hardened skin from the larval stage.

During this stage, the fly undergoes metamorphosis as it transforms into an adult. The duration of the pupa stage also varies depending on environmental conditions and can last from a few days to several weeks.

Adult Stage

The final stage of a fly’s life cycle is the adult stage. Once the fly emerges from the pupa casing, it is fully developed and ready to mate and reproduce.

Adult flies have two wings and a pair of compound eyes that allow them to see in multiple directions simultaneously. They also have mouthparts that are designed for lapping up liquids and other foods.

The lifespan of an adult fly varies depending on the species and environmental conditions. Some species only live for a few days, while others can live for several weeks or months.

Importance of Understanding Fly Life Cycles

Understanding the life cycle of flies is important for controlling their populations. By understanding when and where flies lay their eggs, we can take steps to prevent their reproduction.

One effective method of controlling fly populations is by removing their breeding sites. This includes properly disposing of food waste, keeping garbage cans covered, and cleaning up after pets.

In addition, insecticides can be used to target specific stages of a fly’s life cycle. For example, insecticides can be applied to areas where eggs are laid to prevent them from hatching, or they can be used to kill adult flies before they have a chance to lay eggs.


Flies may be considered pests, but they play an important role in our ecosystem. Understanding their life cycle is crucial for controlling their populations and preventing the spread of diseases they may carry.

By taking steps to remove breeding sites and using targeted insecticides, we can effectively control fly populations and minimize their impact on our environment.