Understanding the Life Cycle of a Flea


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If you want to eliminate fleas from your home and your pet, there are a few things that you should know. Firstly, you must be familiar with its life cycle when eradicating its presence. There are four stages in the life cycle of a flea – egg, larval, pupal, and adult. Depending on the environmental humidity and temperature levels, the life cycle will take weeks or even months. The optimal temperature for fleas is around 70 to 85 degrees Fahrenheit, and they thrive best when the humidity is 70 percent.


The life cycle begins when the adult female lays eggs after having a blood meal from the host’s body. An adult flea needs blood to reproduce. The eggs are white and smaller than a grain of sand. They are laid in the fur of your pet in batches of 20. One fully grown adult can lay up to 40 eggs in one day. Eggs take between 2 days to 2 weeks to develop and hatch when the environmental conditions are suitable. If the temperature is dry and cold, the eggs will take a lot longer. If it is humid and the temperatures are high, they will hatch faster.

Larval Stage

The larvae that emerge from the eggs are blind and try to avoid the light. They develop by eating a flea diet (predigested blood) passed on by the adult fleas, along with any other organic debris they can find in their environment. The larvae can grow up to a quarter of an inch in length and are legless and white. Larvae constitute about 35 percent of the flea population in a household. Under favorable conditions, they spin cocoons a couple of weeks after they hatch out of their eggs. This leads to the pupal stage.

Pupal Stage

The cocoon they spin protects them for days or weeks before they metamorphose into the adult flea. If the surrounding environmental conditions are not right, the cocoon can protect the flea for months and sometimes even years. Since the cocoons have a sticky coating, they can hide deep in your carpeting and cannot be removed by sweeping or light vacuuming. The adult flea won’t emerge until they are sure of the presence of a host – by rising CO2 levels, vibrations, and body heat.

Adult Fleas

Once a flea emerges from the cocoon, it will start to feed off the host within hours. Once they are done with their first meal, they will start to lay eggs within a few days. Female fleas cannot lay eggs till they get a blood meal. Newly hatched adult fleas are flat-bodied and dark in color. Once they feed off your dog or cat, they will become larger and lighter, taking on a more recognizable shape. Adult fleas make up less than five percent of the flea population in an average home.

How to Deal with Fleas

Flea treatment for cats is different from flea treatment for dogs. If you use dog flea pills as flea medicine for cats or vice-versa, it can cause harm. 

Capstar is one brand that caters to both cats and dogs. There is Capstar for Dogs and Capstar for Cats. It's a trustworthy brand that can kill adult fleas. However, Capstar won’t work on eggs or larvae. For something that can kill fleas in whatever stage of the lifecycle they are in, you can try the PetArmor Plus flea and tick spot treatment.

If you want to prevent fleas from attacking your pet, try a flea collar from Seresto. There’s the Seresto Flea Collar for cats and the Seresto Dog Collar for dogs.

For dogs, you can additionally use a flea spray or a flea shampoo for dogs. In addition to these, using a flea comb to brush your dog’s fur will also provide great results.

Flea and Tick Season Is Here: Don't Leave Your Pet Unprotected!

Pet parents must take preventative action to protect themselves and their pets from infestation and disease carried by fleas, ticks, and other pests.

When your pet is infested with fleas, it can cause them to become frustrated and irritated. This can lead to biting, scratching, and even hair loss.

Fleas are also a common cause of skin infections in dogs. The bites can leave tiny red bumps that look like pimples or bug bites on your dog's skin. Fleas can also cause anemia in dogs by sucking blood from their bodies.

Fleas are carriers of tapeworms and other parasites that live in the blood of their hosts. They can cause anemia by taking so much blood from the host that they starve it of nutrients and red blood cells. They also have been known to transmit diseases such as cat scratch fever (CSF) or bartonellosis. Fleas may also be vectors for the life cycle of certain types of heartworm larvae, which cause heart disease in dogs.

If you notice any of these signs on your dog or cat, it's important to take them in for treatment right away!

Applying a once-monthly topical or oral flea treatment will not only kill your pet's fleas but will also prevent a possible reinfestation from occurring. Not sure what kind of medicine to purchase? Check out our Flea and Tick Medications Comparison Chart. Don't wait. Flea and tick season is HERE. Use our handy flea and tick map to assess the risk in your area.

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