Fleas: Understanding the Enemy

Understanding the Enemy: the Flea Life Cycle

Thanks to the flea control products now on the market, flea management is easier than before. Understanding the flea's life cycle will help you better control the fleas around your home.

Fleas are a part of the Siphonaptera order, and have a siphon-like mouth and no wings. There are approximately 2,200 species of fleas, but only a few are problematic to your pets. The cat flea is the cause of most pet and environmental infestations.

From Egg to Adulthood

Fleas are metamorphic, meaning they grow from embryo to adulthood. Similar to butterflies, they evolve from eggs to larvae to pupae to adulthood . (In other terms, eggs to caterpillar to cocoon to adult.) Depending on their environment, it can take as few as 12 to 350 days for cat fleas to go through growth stages and emerge from cocoons. The flea population typically is made up of 50% eggs, 30% larvae, 15% pupae, and only 5% biting adults.

Fleas generally thrive in temperatures ranging from 70 degrees to 85 degrees, but can also survive in temperatures as low as 37 degrees. Most fleas spend winter as adults on infested animals or as pupae in cocoons in areas protected from freezing. Flea populations typically increase about 5 or 6 weeks after warm spring weather begins and escalate during the fall in Midwestern and northern states.

Female fleas can lay up to 50 eggs in a day and about 2000 eggs in her lifetime. Eggs are deposited in a host animal's hair, and the eggs drop off onto bedding, carpet or soil.

After 1 to 6 days, the eggs hatch into larvae, which look like small bristle worms with mouths that can chew. Larvae dislike sunlight and hide in dark places indoors and out, such as grass, soil, carpeting, sand and gravel. Larvae tend to dry up easily and relative humidity less than 50% is fatal. The typical larval stage can last 5 to 11 days, but if the humidity, temperature, and food availability are just right, the larval stage can last up to 3 weeks.

Larvae then spin cocoons at the base of carpeting, under bedding or at the base of grass, where they are protected from insecticides. Outdoor larvae prefer shaded, cool, moist areas. Full-grown adults in the cocoon detect heat, vibrations, and exhaled carbon dioxide, indicating that a host is near. They can remain in the cocoon for weeks or months while waiting for a host. The adults then leave their cocoons, hop onto a nearby host, find a mate, and repeat the lifecycle.

Full-grown Biting Adult Fleas

The newly freed adult flea will leap at any likely warm-blooded host, and can survive as adults for 2 weeks to 6 months, depending on its environment. Newly emerged adult fleas can survive only about a week without a blood meal. Female adult fleas will feed numerous times daily, for up to 3 to 4 hours at a time.

Cat fleas prefer cats and dogs, but human ankles, ferrets or domesticated rabbits can also become hosts. Adult fleas will not leave their hosts on their own free will and must be dislodged or killed with flea control treatments. Grooming and brushing, using a flea comb will dislodge the parasites.

Estimates indicate that for every adult flea found on a pet, about 100 fleas are developing in the pet's environment. It is important to simultaneously treat the fleas on your pet as well as in your home and yard.

Fascinating Flea Facts