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What Are Flea Larvae?

M.R. Anglin
M.R. Anglin

Flea larvae represent the second development stage of a flea’s life cycle. The first stage is the egg. Once hatched, the flea larvae look like little worms and can turn into an adult flea in about two weeks. After the larval stage, a flea will form a pupa where it can transform into an adult flea. The time it takes for a larva to turn into an adult flea depends on factors including heat, humidity, the availability of a host, and the amount of carbon dioxide present.

When they hatch, flea larvae are usually white and grow to be about ¼ inch (a little over 6 mm) long. Their bodies are separated into 13 segments: three thoracic segments and 10 abdominal segments. They have no eyes but are sensitive to light. If a light is shined on them, they usually crawl away from the light and crawl downward — for example, farther down into a carpet. They also respond to vibration, such as by clinging to their hosts’ fur if they detect the animal is about to scratch.

Flea larvae turn into adults in about two weeks.
Flea larvae turn into adults in about two weeks.

Even though they don’t have legs, flea larvae have hairs that allow them to move about 20 feet (about 6 m) from where they hatch. Otherwise, the larvae, as well as other stages of the flea, depend on the movement of the host. The food the larvae eat is often the excrement of adult fleas, which consists of undigested dried blood. Once eaten, this food allows the flea to change color from white to yellow or brown. The larvae can also eat other organic material, but adult flea fecal matter is their main food source.

Flea larvae will shed their skin and leave casings behind as they develop.
Flea larvae will shed their skin and leave casings behind as they develop.

Flea larvae will shed their skin and leave casings behind as they develop. This shedding can happen three times. Since the larvae don’t move very far from where they hatch, the discarded casing can signal where the larvae are located. Once they reach the third shedding, the next stage is the pupae stage. The larvae will gather up debris such as hair, carpet fibers, lint, and other materials to create a camouflaged cocoon in which they can develop into adult fleas.

Both flea eggs and flea larvae are susceptible to drying out or desiccating. Thus, fleas usually live and develop best in higher humidity areas. This phenomenon also makes the larvae and eggs susceptible to desiccants, a substance that can dry them out. Some desiccants can also perform double duty. A manufacturer may coat flea larvae food with a poison which can both dry them out and poison them if ingested.

Frequently Asked Questions

What are flea larvae and where do they come from?

Flea larvae emerge from eggs laid by adult fleas on a host animal. These tiny, worm-like creatures are the second stage in the flea life cycle. They avoid light and burrow deep into carpets, bedding, or soil, feeding on organic debris and adult flea feces, which contain undigested blood, to grow and eventually pupate.

How long do flea larvae live before they become adult fleas?

The lifespan of flea larvae can vary, but typically they live for about 5 to 11 days before they spin cocoons to become pupae. Environmental conditions like temperature and humidity play a crucial role, with optimal conditions speeding up their development. In less ideal circumstances, larvae can live for several weeks before pupating.

What conditions are favorable for the development of flea larvae?

Flea larvae thrive in warm, humid environments. They require temperatures of 70-90°F (21-32°C) and a relative humidity of 70-85% to develop properly. Such conditions are often found in homes, especially in carpet fibers, pet bedding, or upholstered furniture, where larvae can find the organic matter they need to feed on.

Can flea larvae infest humans like adult fleas?

Flea larvae do not infest humans; they are not equipped to bite or live on a host like adult fleas. Instead, they remain hidden in the environment, feeding on organic debris until they mature into pupae. However, their presence indicates an underlying flea infestation that could lead to adult fleas biting humans.

How can I tell if I have flea larvae in my home?

Identifying flea larvae can be challenging due to their small size and tendency to avoid light. Look for tiny, white, worm-like creatures in areas where pets rest or in dark, humid spots like under furniture. Flea dirt, which looks like small black specks and is actually flea feces, can also indicate larvae presence.

What are the best methods to eliminate flea larvae?

To eliminate flea larvae, thorough cleaning is essential. Vacuum carpets, furniture, and pet areas regularly to remove larvae and their food sources. Wash pet bedding in hot water weekly. Professional insecticides and growth regulators can target larvae specifically. Ensuring your pets are treated with veterinarian-approved flea control products will also help break the life cycle.

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    • Flea larvae turn into adults in about two weeks.
      By: Cosmin Manci
      Flea larvae turn into adults in about two weeks.
    • Flea larvae will shed their skin and leave casings behind as they develop.
      By: dabjola
      Flea larvae will shed their skin and leave casings behind as they develop.