How do lice reproduce on a human? - briefly
Female head lice deposit 6‑10 eggs daily, gluing each nit to a hair shaft near the scalp. The eggs hatch in 7‑10 days, and the emerging nymphs reach maturity in roughly another week, completing the reproductive cycle.
How do lice reproduce on a human? - in detail
Pediculus humanus capitis and Pediculus humanus corporis complete their life cycle entirely on a human host. Adult males locate females by detecting pheromones and tactile cues, then mount the female for copulation that lasts several minutes. A single mating event can fertilize the female for her entire reproductive period.
After insemination, the female deposits eggs, called nits, on hair shafts or clothing fibers. She uses a specialized cement gland to attach each egg at a 45‑degree angle, ensuring stability. A fertilized female can lay 5–7 eggs per day and up to 150 eggs over a lifespan of 30–40 days. Eggs are laid in clusters near the scalp where temperature is optimal.
Egg development proceeds through an incubation phase of 7–10 days at typical human body temperature (≈37 °C). During this time the embryo undergoes segmentation and formation of appendages. Once the operculum opens, the newly hatched nymph emerges.
Nymphs pass through three successive molts before reaching adulthood. Each instar lasts 3–5 days, during which the insect requires a blood meal to obtain the protein needed for molting. After the final molt, the adult is capable of reproduction and can survive another 20–30 days if regular feeding continues.
The complete generation cycle—from egg to reproducing adult—takes roughly 2–3 weeks. High reproductive output, short developmental intervals, and constant attachment to the host enable rapid population expansion under favorable conditions.