When can lice lay eggs? - briefly
Adult female headlice become capable of oviposition roughly five to seven days after emerging from the nymph stage. They then deposit one to two eggs daily for up to several weeks.
When can lice lay eggs? - in detail
Lice reproduce through a defined cycle that begins once a female reaches sexual maturity. After the nymphal stages, a female becomes capable of oviposition at approximately 5 – 7 days post‑hatch, when she is fully engorged and has completed her final molt. From this point onward she continuously deposits eggs.
The rate of egg deposition is steady. A mature female typically lays one to three eggs per day, accumulating 30 – 50 eggs over her lifespan of about three weeks. Egg‑laying continues until the female dies or is removed from the host.
Several factors modulate the onset and intensity of oviposition:
- Temperature: Optimal ambient temperatures (28 – 32 °C) accelerate maturation and increase daily egg output. Cooler conditions delay sexual maturity and reduce laying frequency.
- Host blood availability: Frequent feeding provides the nutrients required for egg production; prolonged periods without blood meals can suppress egg‑laying.
- Crowding: High lice densities may trigger earlier reproduction, while extreme overcrowding can inhibit it due to competition for feeding sites.
Each egg, commonly called a nit, is cemented to hair shafts within 24 hours of being laid. Incubation lasts 7 – 10 days, after which the nymph emerges and begins its own developmental phases. Consequently, the entire reproductive window—from the first egg laid to the emergence of the last nymph—spans roughly three weeks.
Understanding this timeline is critical for effective control measures. Treatments applied before the first eggs are deposited prevent the establishment of a viable egg bank, while repeat applications timed at 7‑day intervals target emerging nymphs before they mature and resume laying.