How many lice hatch from an egg? - briefly
One louse emerges from each egg, producing a single nymph when it hatches.
How many lice hatch from an egg? - in detail
Each egg produces a single nymph. The egg, commonly called a nit, contains one embryo that develops into an immature louse. Hatching occurs after an incubation period of 7–10 days, depending on temperature and humidity; optimal conditions (≈30 °C, 70 % relative humidity) accelerate development, while cooler or drier environments delay it.
Key points:
- Embryonic count: One embryo per egg, therefore one hatchling per egg.
- Incubation range: 7 days at 30 °C, up to 12 days at 20 °C.
- Environmental influence: Higher humidity shortens the period; low humidity can cause egg mortality.
- Species consistency: Head lice (Pediculus humanus capitis), body lice (P. h. corporis), and pubic lice (Pthirus pubis) all follow the one‑egg‑one‑nymph pattern.
- Female output: A mature female lays 6–10 eggs daily, accumulating 100–150 eggs over her lifespan, yet each egg still yields only one individual.
Thus, the definitive answer is that a single egg yields exactly one louse, with the timing of emergence governed by external conditions.