How many nits can a louse lay in a day? - briefly
A female head louse typically deposits five to ten eggs (nits) each day. Egg production may vary with temperature and the insect’s age, but the average daily output remains within this range.
How many nits can a louse lay in a day? - in detail
Head lice (Pediculus humanus capitis) lay eggs, commonly called nits, on the human scalp. A female adult typically produces between 4 and 7 eggs each day. Over her lifespan of about 30 days, an individual can deposit roughly 100–150 nits, assuming continuous egg‑laying activity.
Key points influencing daily egg output:
- Age of the female – Egg production increases after the first week of adult life and peaks around days 10–15.
- Temperature and humidity – Optimal conditions (≈30 °C and 70 % relative humidity) support the maximum laying rate; extreme conditions can reduce it by 20–30 %.
- Host factors – Frequent hair washing or chemical treatments may stress the parasite and lower egg‑laying frequency.
Egg development requires approximately 7–10 days before hatching, so the number of viable nits on a host at any moment depends on both the laying rate and the survival of previously laid eggs.
In controlled laboratory settings, the observed average daily egg deposition is 5.3 ± 1.2 eggs per female, aligning with field reports that cite a range of 4–7 eggs per day under typical human‑host conditions.