The Head Lice Life Cycle

Head lice are a type of insect who tend to use humans as host. Although most people think of them as pests, the head lice life cycle consists of several stages that may be unknown. If you’ve ever wondered about this small insect, they have three distinct stages of life: egg, nymph, and adult.

What you may think of as nits in your hair from head lice are actually the eggs. Often, these eggs are difficult to see since they appear very similar to dandruff or hair spray. Adult female lice lay eggs and actually attach them to the base of the hair shaft, as close to the scalp as possible. They are extremely small in size, oval, and usually a yellow to white color. The nits take only one week to hatch with a range of 6-9 days. The viable eggs are typically located within six millimeters of the scalp or else they may be dislodged.

When the egg hatches, the second stage begins as the nymph is released. The nit shell turns into a more visible dull shade of yellow and stays attached to the hair shaft. The nymph actually appears very similar to an adult head louse but is much smaller, and usually just the size of a pinhead. After molting three times, nymphs are considered mature. This will occur about seven days after hatching.

The adult louse is the final stage and will be about the size of a sesame seed. These lice have six legs which each have claws. They appear to be tan to a gray white in color. In a person with dark hair, lice actually tend to appear darker in color. The female lice are slightly larger than the males and will start laying eggs, about eight every day. An adult louse can live up 30 days on a person’s scalp. In order to sustain themselves, adults will feed on the host’s blood and without these meals, the louse will die within two days.

The entire life cycle of a louse is fairly short and usually only lasts 40 days or fewer. However, during this lifespan, a louse can lay a significant amount of eggs, so even one louse will increase head lice exponentially if left undisturbed. For this reason, head lice are a serious condition and can be difficult to get rid of, so a prompt recognition of the lice and treatment is needed to prevent the life span from continuing.