How long do lice survive without feeding? - briefly
Adult head lice can live roughly one to two days without a blood meal, while nymphs typically die within 24 hours of starvation. Environmental conditions such as temperature and humidity may slightly extend or shorten this survival window.
How long do lice survive without feeding? - in detail
Lice are obligate ectoparasites that require regular blood meals to maintain metabolic functions. Adult head lice can endure a period without feeding that ranges from 24 to 48 hours under typical indoor conditions (temperature around 20‑25 °C, relative humidity 40‑60 %). Their survival time shortens markedly when the environment is dry or cool; at temperatures below 15 °C, mortality can occur within 12 hours.
Nymphs, being smaller and less energy‑dense, survive for a shorter interval without nourishment, generally 12‑24 hours. Eggs (nits) are not dependent on host blood; they remain viable for up to a week, but hatching requires appropriate temperature and humidity, not a blood source.
Key factors influencing starvation tolerance:
- Temperature: Higher temperatures increase metabolic rate, reducing the interval a louse can survive without a meal.
- Humidity: Low humidity accelerates desiccation, leading to faster death.
- Age and physiological condition: Older adults have depleted energy reserves and die sooner than younger individuals.
- Species: Body lice (Pediculus humanus corporis) exhibit slightly longer starvation periods (up to 72 hours) due to a more robust cuticle compared with head lice (Pediculus humanus capitis).
In practical terms, removal of a host for more than two days typically results in the death of most adult lice, though nits may still hatch if environmental conditions remain favorable. Effective control measures therefore focus on eliminating live insects and preventing re‑infestation rather than relying solely on starvation.