Introduction to the Flea

There are four stages in the life cycle of the flea: egg, larva (three stages), pupa (cocoon), and adult. Adult fleas prefer to live on the host animal, but are often dislodged by scratching. Eggs are laid on the animal, but are quite smooth and easily fall off into the environment. Larva hatch from the egg and undergo approximately three molts, progressively becoming larger. Larva live off of organic debris, including flea dirt, the dried blood-feces of the adult flea. The third stage of the flea larva makes a cocoon where the adult flea develops. The egg, larval, and pupal stages almost always take place in the environment off of the animal, where the microenvironment is often ideal for growth. These larvae and cocoons are found deep in carpeted areas or areas with a layer of organic material (e.g., a garden or flower bed). They are protected from insecticides in this hard-to-reach area.

Adult fleas hatch from the cocoon when proper stimulation is present. The stimuli include: vibration, increased carbon dioxide levels, heat, and motion. The adult can emerge from the cocoon in a very short time period...less than a second....and immediately jump to find a proper host. Once on the host they feed on blood obtained by biting through the skin.

An egg may develop into an adult flea within 14 days if conditions are ideal. Each fertilized female may lay as many as 25 eggs per day....more than 800 in her lifetime. In just thirty days, 25 adult female fleas can multiply to as many as a quarter of a million fleas! The main flea affecting the dog and cat is the cat flea, Ctenocephalides felis. There is a dog flea also that occasionally is responsible for flea infestations, but the majority of the time, C. felis is the flea found on dogs and cats. Fleas are insects that are highly developed and can reproduce in copious amounts when environmental conditions are ideal. High humidity and high relative temperatures provide that ideal environment.


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