The Flea Life Cycle On Dogs & Cats

Flea Control Products and Protocols

Client Communications

Flea control is big business, but this business has been going to the grocery stores. The new flea products that are available only through a veterinarian have the potential to change this. Because retail flea control is a multi-billion dollar business, newer “me too” products are being offered by the retailers. This war of flea control products and information has to be fought by the first line of communicators about flea control. Customers want service, they want to understand how to control fleas, and they want to know that they are doing the right thing for their pets. In the grocery store, there is no salesperson and no one to help a customer with the buying decision. By understanding that Program® should be given with a meal, and that Advantage® and Frontline® are far superior than any similar product sold over the counter, you can show the customer the true value of the information provided by your animal health care facility. By understanding the flea life cycle you can answer questions about why the house spray that they are using does not work. By understanding how pesticides work, which ones are toxic, and which ones are inactivated by sunlight, you can help the client choose the good control program for their pets. Fleas are easy to kill but difficult to control; therefore, it is only through intelligent and safe use of these products that we will be successful in satisfying our clients. Our business depends on repeat customer visits and flea control is a great way to generate more repeat visits.


The Flea

The Flea is a wingless, bloodsucking insect of the order Siphonaptera that parasitizes warm-blooded animals. Most are 0.1 – 0.4 cm (0.04 – 0.16 in) long and have enlarged, muscular hindlegs adapted for leaping. Fleas exhibit complete metamorphosis, with a larval form that feeds on organic debris. In the wild, flea larvae subsist on the hair, skin, droppings, and food scraps that accumulate in nests and lairs of animals. They live in the bedding of pets, as well as in dirty rugs, under and in furniture, and any other refuge with the right environmental conditions. The larval stage lasts twelve to two hundred days, and the adults may live almost a year.


The Flea Life Cycle

The life cycle of the common cat flea, Ctenocephalides felis, is comparable to that of a butterfly. Average cycle length is 21 to 28 days and the range is 12 days to 50 weeks. Flea development is the same type of development that a butterfly follows; an egg is laid which hatches into a larva that feeds on dead organic matter (flea dirt) and then forms a cocoon, from which emerges an adult flea. The entire cycle can complete in as little as 14 days. Fleas lay most of their eggs when the temperature is 65°F to 80°F and the humidity is above 70%; so fleas are laying eggs most of the year in the Gulf Coast area. The life cycle needs to be understood to effectively control the fleas in the animal’s environment.

The Flea Life Cycle Stages

Egg Stage


The female lays white round eggs. The eggs are not sticky and quickly fall into the environment where they roll into cracks and crevices. They hatch in two to five days into yellowish –white larvae. The larvae feed on flea feces, the brownish red crusts of blood often referred to as “flea dirt”. An egg may develop into an adult flea within 12 days if conditions are ideal.

Figure 1. Smooth-shelled eggs that roll off of host along with partially digested blood that will become larval food source. The egg stage is easily vacuumed up and discarded.

Larval Stage


After hatching, the larva feeds on organic debris and “flea dirt”. The “flea dirt” meal turns the next larva reddish brown. It grows and molts in one week. The next stage is the opaque white larva which, when grown, spins a cocoon which we call a pupa.

Figure 2. Flea larva that feed on the partially digested blood excreted by adults.

Pupal Stage


The pupa hatches in one to fifty weeks. The length of the life cycle is dependent on several conditions. The larva transforms into an adult flea. Depending on weather conditions, population explosions typically occur five to six weeks after the initial warm-up.

Figure 3. Flea cocoons (pupa). Fleas use whatever material they are living in to make the cocoon.

Adult Stage


Adult fleas spend only short periods of time on the animal (five percent of their entire life). The fleas, unlike mange mites, do not live their entire life on the animal.
By chewing and scratching, the pet makes it dangerous for a flea to live on him. The flea population on the pet today will not be the same population on the pet tomorrow. The adult emerges from the cocoon and immediately searches for a host to feed on. Mating begins immediately. Female fleas begin to lay eggs within thirty-six hours. By the third or fourth day, the female flea can produce 40 to 50 eggs per day (two times its body weight) and will continue to lay eggs for up to one hundred days. Fleas can lay over 2,000 eggs in their lifetime. In just thirty days, twenty-five adult female fleas can multiply to as many as a quarter of a million fleas!

Figure 4. Adult fleas taking blood meal and excreting partially digested blood that will become the larval food source.


Figure 5. Flea Life Cycle – Complete Metamorphosis

The information articles to follow are very detailed so that you can answer most of the common situations that you will encounter in the veterinary facility with regards to flea control. Topics that will be covered include:


Bubonic Plague – Black Death The Oriental rat flea is the primary transmitter of Yersinia pestis, the bacterium that causes…


Our most important function as an animal hospital is for our staff members to understand the disease that fleas cause…


The Flea Colony Many of our clients who are trying to control fleas on their pets do not understand that…


Household Flea Treatment Vacuuming: The household should be thoroughly vacuumed twice weekly. Special attention should be given to areas where…


Advantage® utilizes revolutionary new chemistry to produce unprecedented results on cats and dogs. Advantage® contains imidacloprid, a chloronicotinyl nitroguanidine synthesized…


Organophosphate and Carbamate Pesticides The action of organophosphate and carbamate pesticides is so similar that they will be covered together….


Pyrethrins are insecticides derived from the chrysanthemum plant. They have good “knockdown” and are relatively safe when properly applied for…


Puppies Less Than 8 Weeks Use flea comb multiple times daily Apply d-limolene shampoo according to label instructions Apply methoprene…