Fleas’ Survival Guide: Blood Dependency and Life Span
An average flea can live for only four days to a week without blood. This is the reason why adult fleas may remain inside their cocoon until the outside conditions signal that a host is present.
Fleas require constant feeding to survive and this is why they prefer living on a host. Another thing that is worth to note is that a female flea cannot lay any eggs until it gets its very first blood meal.
When a flea is removed from its host, it will starve and die in just four days. A young flea that hasn’t fed yet may be able to survive for a little bit longer up to a week even without a blood meal. A pre-emerged adult that stays inside its cocoon can enter a dormant-like state and can live for as long as 155 days with no feeding at all.
Life Span of Adult Fleas Inside Cocoons
After pupating, an adult flea can remain dormant-like or quiescent inside its cocoon for a long period. They have a slowed-down metabolic activity that allows them to survive with no food. Depending on the specific ambient temperature, the emergence from the cocoon can be delayed for up to five months. But, the quiescence can end right away once they detect a nearby host.
Life Span of Emerged and Unfed Adult Fleas
After it emerges from its cocoon, an adult cat flea needs to look for a host immediately. Without blood, it will die of starvation in one week under normal household conditions.
An unfed adult can live a bit longer in more humid and favorable environments. They can survive for up to 15 days at a relative humidity of 78% and temperature of 75.2°F (24°C). At 60% RH and 72.5°F (22.5°C), they will live for 12.3 days.
The ideal survival conditions occur in very humid and cool environments. It was observed that there were unfed fleas that were able to survive for as long as 40 days, with more than half of the emerging adults surviving for 70 days in saturated and cool air. However, it is very rare for such conditions to occur in natural environments or homes.
Malnourishment of Fleas Removed from the Host
Fleas start feeding right away after finding a host, usually in less than one minute. After feeding for 24 hours, a flea that used to be unfed will have its weight almost doubled and the soluble protein content tripled. Once removed from its host with 12-hour starvation, all the protein and gained weight is lost. This means that a flea needs to feed every 12 hours at least for it to remain well-nourished.
Dependency on Blood and Starvation of Fleas
Fleas often die of starvation four days after they are removed from a host. Once young fleas acquire a host and start feeding, they will cross a dependency threshold in a matter of days. After they reach this point, the flea needs a constant blood source for it to survive.
When a flea is fed from its host for five days and is removed, it will die within 2 to 4 days. If the feeding time was only limited to 12 hours, a flea wouldn’t be able to reach the dependency threshold and might be able to survive for 14 days after it is removed from its host.
Female Fleas Starve Sooner Than Male Fleas
Fleas are considered anautogenous and this means that they need the blood of a host to have a successful mating and reproduction. Females also require a blood meal before each egg deposition. This is why actively reproducing females need to feed continuously so that their metabolism remains balanced for the production of eggs. These females might die in just 24 hours after they are removed from the host.
How Long Can Fleas Live with Blood or a Host?
In general, adult fleas can live for 2 to 3 months with regular access to their host. The life span of the parasite is also dependent on some other external factors. The ideal conditions for fleas are 85 degrees F and 85% relative humidity.
How Do Fleas Feed?
Fleas exclusively live on blood. These parasites favor hairy animals such as cats, dogs, mice, rats, rabbits, possums as well as other domesticated or wild animals. But, if there are no furry animals that are their preferred hosts, fleas will also be more than happy to feed on a human host.
The parts of the mouth of a flea are specifically suited for blood-sucking. A couple of these parts come together for this particular purpose. The laciniae are the two parts that resemble a saw and are in charge of cutting the host’s skin. the epipharynx is the part that resembles a needle and sits at the center on either side of the two laciniae. These organs all form the style that will pierce the skin.
Fleas pierce or cut the skin open to reach the blood vessel and use their epipharynx for suctioning blood for feeding purposes. They also simultaneously inject an anticoagulant to prevent blood clotting while they feed. This chemical may cause allergic reactions in some pets and humans.
Fleas can feed daily when the conditions are ideal. An average flea consumes as much as 15 times the weight of its body in blood. An adult flea can feed for up to one hour before it becomes fully engorged. Fleas often feed at least one time every 12 hours.
What Happens If There is No Transfer to a Host?
The countdown to the blood meal starts right after a flea emerges from its cocoon as a fully-formed adult. The metabolism of the flea speeds up once it is out in the outside world and this is why it must feed on the blood of a host at the soonest time possible.
Starvation takes place with no immediate feeding on blood. Fleas in general can live for a maximum of one week with no food and outside their larval cocoon without necessarily dying of starvation.
