The Flea Lifecycle: Know Your Enemy

Fleas can make your cat itch and cause considerable discomfort. Because cats groom themselves often, you might not even see fleas. But an unseen flea can begin feeding on your cat within seconds. Within 24 hours of its first blood meal, a flea can begin laying eggs at a rate of 40–50 per day1, resulting in an infestation.

To protect your pet and home from fleas, it helps to understand the flea lifecycle.

The egg stage

Adult fleas can begin feeding within seconds of finding a host. They must feed to begin reproduction, and female fleas will begin producing eggs within 24 to 48 hours of taking their first blood meal2.

Female fleas can produce 40 to 50 eggs per day, up to 2,000 in their lifetime2. The eggs readily fall off the hair into the environment, so you can think of your cat as a flea-egg “salt shaker.” Wherever the pet spends the most time is usually where the heaviest flea infestations are found.

The larval stage

Larvae hatch from eggs in one to six days given appropriate environmental conditions (a relative humidity between 50 percent and 92 percent)3,4. Their principal food is adult flea feces (“flea dirt”).

Flea larvae are small, thin and white, measuring 1 to 2 millimeters in length (about the thickness of a dime). Indoors, flea larvae tend to live deep in carpeting or under furniture. Outside, they develop best in shaded areas or under leaves or similar yard debris. Any area of a yard where a pet seeks shelter from the heat or cold is potentially a great environment for fleas.

The pupa stage

A mature larva transforms into a pupa inside a silk cocoon. Under most household conditions, the adult flea will emerge in three to five weeks. However, if the pre-emerged adult does not receive the proper stimulus to emerge, it can remain inside the cocoon for months until a host arrives3,5, a reproductive strategy that enhances the flea’s chance of survival. This helps to explain how a flea infestation can seemingly “explode” out of nowhere, even inside your home.

The adult stage

Adults emerging from cocoons can begin feeding immediately if a host is present. They are attracted by body heat, movement and exhaled carbon dioxide2.

The flea feeds through a tiny, slender mouth part called the proboscis. Before feeding, it pumps saliva, which contains an anticoagulant, onto the skin. This prevents the blood from clotting, and the protein it contains can cause a severe allergic reaction in the host (flea allergy dermatitis).

Adult fleas can survive throughout the winter on pets as well as on wildlife.

Cheristin® for cats kills fleas fast, helping you protect your cat and your home from these parasites and the diseases they can carry.

  • 1. Dryden, M.W. Integrated Flea Control. Flea Control in the 21st Century, presented at the North American Veterinary Conference, January 2001.
  • 2. 2005 Flea Guidelines, Flea control for dogs and cats, Advanstar Veterinary Healthcare Communications, sponsored by an educational grant from Meria
  • 3. Rust MK, Dryden MW. The biology, ecology, and management of the cat flea. Annu Rev Entomol. 1997;42:451-73.
  • 4. Dryden, M.W., 2005 Flea Guidelines, Flea control for dogs and cats, Advanstar Veterinary Healthcare Communications, sponsored by an educational grant from Merial.
  • 5. Fleas and Flea Allergy Dermatitis. In Kahn CM ed. The Merck Veterinary Manual. 9th ed. Merck & Co., Whitehouse Station, NJ. 2005:710-715.

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