To understand the importance of using a flea or flea/tick product on your animal, it might
first be helpful to understand the pests themselves.
Fleas (the thought of which makes me itch just writing this article!) are blood-sucking
insects that prefer mammalian hosts. In fact, 95% of fleas use mammalian hosts to survive.
These hosts, of course, include your pet dogs and cats, and may include you as well!
Like mosquitoes and other skin-biting insects, flea saliva contains an ingredient that softens
and breaks down skin in order for the flea to more easily penetrate the skin and suck the blood.
Flea saliva is irritating and allergenic, and is what causes the itching and irritation after
being bitten. The allergic condition from this reaction to the saliva is called Flea Allergy
Dermatitis, or FAD.
The Life Cycle of A Flea
A flea’s life cycle consists of 4 stages: egg, pupa, larva and adult. We are most familiar
with the adult stage, because they are easier to see, but where there are adults present, there
are also fleas in the other 3 stages, you just can’t see them easily with the naked eye.
Egg: Female adult fleas are prolific egg layers, sometimes laying 50 eggs a day, and up
to 500-600 over the course of several months. The eggs are not sticky and most do not stay on
the host animal after being hatched. They fall off the animal into carpeting, bedding,
upholstery, floorboards or soil...wherever the animal goes or has been, and can hatch in two
weeks or so. At this point the larvae emerge.
Larval: When the larvae emerge, they are about 1/4” long and actively move.
They eat adult flea feces (dried blood) and other organic debris found in the same places as
the eggs...carpet, bedding, soil etc. Depending on environmental conditions (more on that
later) the larval stage can last about 5-18 days. Once that stage is complete, the larvae
spin a cocoon and go into the pupal stage.
Pupal: The pupal stage is the last stage before emerging as an adult flea. This
stage can be as early as 3-5 days, or as long as a year. Pupae need the right environmental
factors to emerge. This is usually the warm ambient temperatures and high humidity associated
with summer weather, but these conditions can be mimicked under certain circumstances in your
home even during the winter, so the pupae can hatch into adult fleas at any time, giving some
folks thought about applying flea preventive even during the winter months.
Adult: The adult flea is flat-bodied, and has hair-like bristles which enable it to
move quickly through the fur (or hair) of their hosts. If you have ever tried to chase a flea
on your pet, now you know why they can move so fast! Fleas are known for their jumping ability,
and they have 3 pair of legs to help them do so. Unlike the eggs, pupae and larvae, adult
fleas prefer to live on the host animal, sucking their blood and making them miserable.
Once you understand the life cycle of the flea, you can understand why it’s important to
protect your pet from these blood-sucking critters on a year round basis. One month of
missed treatments can allow fleas to reinfest your pet, starting the cycle all over again.
Makes me itch just thinking about it!