Egg -- Flea eggs are shiny, white, oval, and are about 0.5 mm long.
Larva -- Flea larvae vary in length from 4 to 6 mm when mature and are slender, white, cylindrical and legless with 10 to 12 moderately long setae on each body segment. The pale brown head has no eyes.
Pupa -- The pupa is shaped somewhat like the adult and develops in a white, oval, silken cocoon about 4 mm long which is often covered with sand, lint, or dust.
Hosts -- Practically all warm-blooded animals are fed upon by fleas. Each species of flea, however, usually feeds on a limited number of specific animals. In North Carolina, the cat flea is the most common pest of cats, dogs, and the most common annoyance to man. Sticktight fleas are occasionally found damaging poultry.
Damage -- Flea bites cause a persistent, annoying itch. Constant biting and scratching by infested animals causes the skin to be irritated. Young chickens and other poultry may even be killed by heavy sticktight flea infestations.
Life History -- Fleas may feed and breed throughout the year but development often slows during the winter months because of low temperatures. Females deposit eggs on the host a few at a time. Eggs usually fall off host animals and hatch in 2 to 14 days. Larvae generally feed on organic matter such as excrement from adult fleas and domestic animals. Immature fleas can develop indoors in carpeting and overstuffed furniture. After 1 to 5 weeks, larvae spin cocoons and pupate. Under favorable conditions, a new generation of adults emerges 1 to 3 weeks later. An entire life cycle may be completed in as few as 2 or 3 weeks, but several months to 2 years may elapse if conditions are unfavorable.
Adult fleas cannot breed without feeding on blood. However, unfed adults of some species may live 1 to 2 years without feeding, and fed adults can survive 500 days without another meal. Temperatures of 18 to 20oC (65 to 80oF) and a humidity of about 70% are optimum for flea development.