Understanding the Flea Life Cycle


There are four distinct stages in the flea life cycle and during each of these stages the common flea can only be killed by specific pesticides, chemicals or natural remedies. Unfortunately, there is no such thing as a one-size fits all solution to the eradication of a flea infestation.

If you roam the aisles of a pet supply store and search for flea and tick control products you will find that most of the products contain more than one active ingredient.  Each of these active ingredients kill fleas in a specific stage of their lifecycle.  Consequently, if you use an inferior product, you may succeed in killing the adult fleas only to see the eggs and larvae grow into adults and re-infest your animals and home.

Flea Eggs – Stage 1

Flea eggs are clear to milky white and when laid by females onto their host they are wet, but not sticky, per se. These eggs will eventually dry and fall off the animal.  Some will fall off out in the yard or on the sidewalk and eventually die most likely due to being deprived of a host and blood source upon hatching.  A significant number will fall off in the area in and around where the animal or cat spends most of their time.  For example, their bedding will surely be littered with flea eggs if your pet has been infested.

Thus, it is essential that you thoroughly clean and wash animal bedding if you suspect your animal is infested with fleas.

Eggs can hatch after as few as 48 hours or they may take a couple of weeks or more.  The length is dependent upon several factors, including environmental conditions and whether or not insect growth regulators found in some flea treatment products has been used.

Flea Larvae – Stage 2

Little wormlike larvae will emerge from the eggs.  They lack eyes or legs and slither around looking for something to feed on.  Their diet consists of dried blood and adult flea fecal matter which is high in blood content.  The microscopic flea dirt (i.e. flea feces) and dried blood dander falls off the cat or dog each time it lays down in its rest area. This can include bedding, floors, soil and grass areas in the backyard, etc. The worms feed on this organic material until it begins to form a cocoon.

The larvae period can extend for a duration of 1-3 weeks with the length dependent upon the amount of food in the area.  The greater the supply of food the faster the process.

Pupa – Stage 3

The third and final stage before reaching adulthood is the pupa stage.  Inside the cocoon, the work larvae transforms itself into an adult flea before emerging to become a ravenous blood sucking machine and leaves flea bites on you and your pets.  Although the time spent in the cocoon is usually very short (3-7 days), these little buggers can stay holed up on their cozy confines for a year or more.

This is probably the most fascinating and interesting stage, because you may be wondering what signals them to emerge from their cocoon and become these hated and annoying pests.  External environmental conditions consisting of warm, humid weather seem particularly conducive to their emergence. Believe it or not, they are very responsive to carbon dioxide, movement and noise.  This is one reason many people may go away for a trip and suddenly experience a flea infestation upon returning.  Their noise and movement around the house triggers the completion of the metamorphosis.  They also respond to pressure as it signals to them that a host is nearby and that they will supply them with the blood-food it needs to survive.

Adults – Stage 4

Upon emerging from their pupae, fleas are then officially adults and possess the physical tools to suck blood. They cannot reproduce until they consume enough blood.  The adult female flea is a prolific egg layer – up to 50 or more, per day!  Though an average adult flea may only live a couple months or more, the entire life cycle of a flea can last a couple of months in total to more than two years depending on circumstances.

This completes our look at the flea life cycle.