How many eggs does a louse lay? - briefly
A single louse typically deposits 4–6 eggs per day, reaching a total of about 10 eggs before its lifespan ends. Under favorable conditions the eggs hatch within 6–9 days.
How many eggs does a louse lay? - in detail
A female head louse typically deposits between six and ten eggs each day. Over a lifespan of about 30 days, a single adult can lay roughly 200–300 eggs, depending on environmental conditions and host health. Egg laying begins shortly after the female reaches sexual maturity, which occurs around the fourth nymphal stage (approximately five days after hatching).
Eggs, commonly called nits, are cemented to the base of hair shafts near the scalp. The cement hardens within a few hours, making removal difficult without specialized tools. Each egg measures 0.8 mm in length and contains a fully formed embryo. The incubation period lasts 7–10 days at typical human body temperature (≈37 °C). After hatching, the nymph immediately begins feeding and will molt three times before reaching adulthood.
Body lice (Pediculus humanus corporis) exhibit similar reproductive capacity but tend to produce slightly fewer eggs, averaging five to eight per day. Their total egg output per adult ranges from 150 to 250, reflecting the shorter lifespan of about 20–25 days. Pubic lice (Pthirus pubis) lay fewer eggs, roughly three to five daily, with a total of 100–150 over a 30‑day lifespan.
Key reproductive parameters:
- Daily egg output: 3–10, varying by species.
- Total eggs per female: 100–300, species‑dependent.
- Incubation time: 7–10 days at 37 °C.
- Time to sexual maturity: 5–7 days after hatching.
- Adult lifespan: 20–30 days.
These figures provide a comprehensive overview of egg production across the three human‑infesting louse species.