How long does an adult louse live? - briefly
Adult lice typically survive for about four to six weeks, depending on species and environmental conditions. Their lifespan ends when they exhaust their blood meals or encounter hostile factors such as treatment or host grooming.
How long does an adult louse live? - in detail
Adult lice, belonging to the genera Pediculus (head louse) and Pthirus (body louse), complete their life cycle in roughly one month. After hatching from an egg, the nymph passes through three molts before reaching maturity. Once adult, the insect requires a blood meal every 3–4 hours and can survive several days without feeding, but mortality increases sharply after two weeks of starvation.
Typical lifespan under optimal conditions:
- Head louse (Pediculus humanus capitis): 30–45 days.
- Body louse (Pediculus humanus humanus): 30 days, occasionally extending to 35 days.
Factors influencing duration:
- Ambient temperature: 15–30 °C supports maximal longevity; temperatures above 35 °C accelerate metabolism and reduce survival.
- Host hygiene: frequent washing and removal of infested clothing diminish available feeding sites, shortening life expectancy.
- Availability of blood: continuous access extends lifespan; prolonged periods without a host lead to death within 5–7 days.
Maximum recorded survival without a host does not exceed 10 days, while individuals maintained on a well‑nourished host can live up to 45 days before natural senescence. The adult stage therefore represents a relatively brief but reproductively intense phase, during which a single female can lay 4–5 eggs per day, producing a new generation before her death.