How long can lice live without food? - briefly
«Head lice can survive without a blood meal for approximately five to seven days, with some reports of up to ten days under optimal conditions.»
How long can lice live without food? - in detail
Lice are obligate ectoparasites that require regular blood meals to complete their development. When a host is unavailable, survival depends on species, developmental stage, temperature, and humidity.
Adult head lice can persist without a blood meal for up to three days under optimal conditions (moderate temperature, 70‑80 % relative humidity). Beyond this period, physiological stress leads to rapid decline in mobility and eventual death. Nymphs, being smaller and having lower energy reserves, survive for a shorter interval, typically 24‑48 hours without feeding.
Body lice exhibit a slightly longer tolerance. Adults may endure starvation for approximately five days, while nymphs survive for 48‑72 hours. The increased resilience is linked to their ability to ingest larger blood volumes during feeding, providing greater energy storage.
Environmental factors modify these limits:
- Temperature: At 30 °C, metabolic rate rises, shortening survival to 1‑2 days for adults. At lower temperatures (10‑15 °C), metabolic demand drops, extending survival up to 4‑5 days.
- Humidity: High relative humidity (≥80 %) reduces desiccation risk, supporting the maximum starvation periods noted above. Low humidity accelerates water loss, decreasing survival by 30‑50 %.
- Host availability: Frequent host contact (e.g., in crowded living conditions) reduces the likelihood of prolonged starvation, maintaining population stability.
In summary, the maximum duration without a blood meal ranges from one day for early‑stage nymphs to five days for adult body lice, with temperature and humidity exerting significant influence on these values.