Flea Life Cycle

Fleas are holometabolous, blood-sucking parasites that play the role of carriers for various diseases. Parasites are organisms that rely on other organisms called hosts for nutrients. Unlike other insects such as dragonflies, honeybees and grasshoppers, fleas undergo complete metamorphosis. This means that the organism undergoes through four distinct stages before becoming an adult. Fleas are a bane for animal owners as well as most other warm-blooded animals with hair or fur.

An average flea has no wings but a hard exterior. Its total body length ranges between 0.1 cm to 1 cm. Flea’s primary source of food is blood, usually from mammals. A flea infestation can cause severe inflammation of the skin as well as skin irritation. Some fleas are also vectors of many diseases. The species of fleas that have human hosts are known as Pulex irritans, also called ‘human fleas’.

Complete Metamorphosis

As stated before, fleas go through complete metamorphism, which means it has four stages in its life cycle, namely:

  • Egg stage
  • Larvae stage
  • Pupa stage
  • Adult stage

Typically, fleas go through these stages in 14 to 140 days depending on the weather conditions and other environmental factors.

Life Cycle of Flea

Stage 1 – The Egg

The male and female fleas prefer a warm and humid environment for mating. After mating, tiny pearl-like eggs are laid on the surface of the host. These eggs persist on the debris of the host such as parts of dry skin, dried excrement, and dried blood. A female flea lays around 50 eggs. In favourable conditions, the eggs hatch in around 12 to 14 days.

Stage 2 – The Larvae

The larvae emerge out of the egg without eyes, legs and take shelter on mammals or the nearest carpet fibres it can find. The flea larvae are different from adult larvae as it does not feed on blood but consume scales of dry skin, dried debris, food particles, and dead insects. If not vacuumed from the carpet or cleaned from the cracks of the floor, flea larvae can survive up to 18 days. At the end of this stage, the larvae spin silk cocoons and enter the pupa stage. Larvae attach dirt and other debris in order to camouflage and protect then till they transform into the pupa stage.

Stage 3 – The Pupa

Since the flea larvae have not developed any physical parts of their structure, in the pupa stage, the flea develops all organs in humid conditions. If the environment is humid and favourable, then the adult flea emerges in a week. If the conditions are not favourable, then pupa can take a year to become an adult flea.

Stage 4 – The Adult

The adult flea feeds on the blood of the host and leaves blood debris that appears as black particles on the exterior of the host. These black particles are visibly noticeable on the fur of dogs and cats who have fleas. The next thing an adult flea does is hunt for a host to reside, lay eggs and feed blood.


A flea is considered a menace as they are carriers of several diseases like plague, cat scratch disease, typhus and many more. A flea infestation can be easily noticed on an unhygienic pet like dogs and cats.

Read More: Dragonfly Life Cycle

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Frequently Asked Questions on


What causes a flea infestation?

Unhygienic conditions, cracked floors and carpets are where fleas usually stay. The flea transfers when a dog or cat sits on the carpet or floor; the flea prefers to stay in the animal’s belly as it is easy to move from belly to the carpet when they sit down. Fleas require warm and moist living conditions. Therefore flea manifestation is higher during summers.


How to stop a flea infestation?

In order to stop a flea infestation, one has to clean themselves, their pets and their entire household to ensure that all the fleas and the eggs they laid are completely removed. Applying anti-itch lotion or cream on fleabites, anti-flea shampoos for pets and vacuuming the entire house can help in eliminating the flea infestation.


How does a flea bite look like?

Tiny red spots wrapped with red halos appear when a flea bites a human. In animals, the red spot is bigger, bulged and causes much itching.


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