How many eggs do head lice lay? - briefly
Female head lice lay about five to ten eggs each day, accumulating up to roughly one hundred eggs during their lifespan. Eggs hatch in seven to ten days, enabling rapid population growth.
How many eggs do head lice lay? - in detail
Female head lice typically deposit five to ten eggs each day. Over an average lifespan of three to four weeks, a single adult can produce roughly 100 eggs. The eggs, commonly called nits, are cemented to the hair shaft close to the scalp, where temperature remains constant.
The reproductive output depends on several variables:
- Ambient temperature: higher temperatures accelerate metabolism, allowing slightly more frequent laying.
- Host blood availability: well‑nourished hosts provide more resources, supporting increased fecundity.
- Louse health: parasites free from disease or chemical exposure tend to lay near the upper end of the range.
Egg development proceeds as follows:
- Deposition: the female attaches the egg at a 45‑degree angle to the hair strand.
- Incubation: embryogenesis requires seven to ten days under optimal conditions.
- Hatching: the emerging nymph emerges with a fully formed exoskeleton and begins feeding immediately.
After hatching, the nymph undergoes three molts over approximately ten days before reaching adulthood, at which point egg production commences. Continuous egg laying sustains the infestation, making prompt removal of nits essential for control.