How many eggs does a head louse lay? - briefly
A female head louse typically deposits 6–10 eggs per oviposition, up to about eight per day, resulting in roughly 30 eggs over her lifespan. Egg production ceases once the adult dies.
How many eggs does a head louse lay? - in detail
A female head louse typically deposits between 4 and 6 eggs during each reproductive cycle. The cycle lasts about 24 hours, after which the adult seeks a new feeding site on the scalp. Over her lifespan of roughly 30 days, a single female can lay a total of 70–100 eggs, assuming optimal temperature (29‑32 °C) and humidity (70‑80 %).
Key factors influencing egg production:
- Temperature: Below 20 °C the oviposition rate drops sharply; above 35 °C egg viability declines.
- Host availability: Frequent grooming or chemical treatment reduces the number of viable attachment sites, limiting the number of eggs a female can lay.
- Nutritional status: Adequate blood meals are required for each batch of eggs; insufficient feeding leads to smaller clutches.
Eggs, commonly called nits, are cemented to hair shafts within 1 mm of the scalp. They hatch after 7‑10 days, releasing nymphs that mature to adulthood in an additional 9‑12 days. Because each adult female can produce dozens of eggs, infestations can expand rapidly if untreated. Effective control measures must target both the adult lice and the attached eggs to interrupt this reproductive capacity.