Flea Life Cycle

Life Cycle Stages

Fleas undergo complete metamorphosis. The life cycle, or stages, of the flea is composed of the egg, larval, pupal, and adult stages. Cycle length ranges from several weeks to several months and is largely dependent upon environmental conditions.

Photo of Flea That Just Finished Feeding

Fleas lay between four to eight eggs after a meal, with the highest concentrations of laying occurring within the last few days of the female’s life. Unlike the eggs of some other parasites, flea eggs are not sticky and usually fall to the ground immediately upon being laid. Flea eggs hatch into larvae within one to 12 days.

Once away from the host, the larvae seek out shaded locations such as:

  • Carpets
  • Cracks in the floor
  • Pet bedding
  • Protected locations in & under furniture

Flea larvae complete three larval instars, and depending on their environment will range in length from about 3 to 5 mm long. They have no eyes or legs, and their body is maggot-like and whitish, but turns progressively darker as the larvae feeds on feces excreted by the adult fleas. Unlike adult fleas, larvae do not take a blood meals directly from a host.

Besides feces, they will feed on various types of organic matter such as:

  • Dead insects
  • Dead skin
  • Feathers
  • Food particles

Flea larval survival depends on relative humidity and temperatures. Since dehydration is fatal to flea larvae, they will not survive relative humidity less than 45 to 50 percent or soil temperatures greater than 95 degrees Fahrenheit. However, outdoor larvae will survive in cool, shaded areas and do very well in crawl spaces. In environments of suitable humidity and temperatures, fleas will develop year round.

The flea’s larval stage is completed within about 4 to 18 days. One of the last activities of flea larvae is to spin a silken cocoon and then enter the pupal stage. The pupal stage may be complete within three days, or it can last as long as one year.

Adult fleas begin searching for food when they emerge from the pupal stage. While fleas are noted for their jumping abilities, they will remain stationery when a suitable host is located. Females begin laying eggs within 48 hours of the first feed, thus beginning the life cycle again.

Encounters & Concerns

Eggs are very small and not likely to be observed by homeowners. Flea larvae and pupae are relatively inactive, so that means the adult stage of the life cycle is most likely to be seen by homeowners.

Some typical examples of visible adult flea activity or infestation scenarios are:

  • Adults jumping from furniture or the floor onto people or pets.
  • When an infested home has been vacant for several days, adult fleas seem to appear out of nowhere and aggressively jump on to pets and peoples upon their return.
  • Fleas observed on the hairless parts of pets and seen when combing or grooming.
  • The pests seen floating in bathwater of pets.
  • Evidence of bites on people or pets. Flea bites on the skin are typically red, swollen, and itchy.
  • Adults observed in carpets or pet bedding and sleeping areas.
  • Presence of “flea dirt” (adult fecal droppings) in the animal’s fur.
  • Pet behavior that involves excessive scratching.
  • Skin and hair of infested animals that is red or is falling out.

Concerns of homeowners include skin irritation and the health and welfare of both homeowners and pets. Adult flea bites can result in the transmission of diseases to both homeowners and pets. Flea problems in and around homes may be an indication of a rodent or other mammal infestation nearby.

Some of the more commonly encountered flea-borne diseases affecting people worldwide include:

  • Bartonellosis
  • Flea tapeworm
  • Murine typhus
  • Secondary bacterial infection

Some animal diseases transmitted by fleas can include:

  • Acanthocheilonemal reconditum
  • Bartonellosis
  • Dipetalonema reconditum
  • Flea tapeworm
  • Murine typhus
  • Rickettsia felis


More Information: