How often do lice bite? - briefly
Lice feed by biting the scalp several times a day, typically every 4–6 hours, but they do not bite continuously. Their activity increases when they are hungry or when the host’s blood flow is easier to access.
How often do lice bite? - in detail
Lice feed by piercing the skin and ingesting blood, a process that triggers the bite sensation. The interval between feeding events varies with species, life stage, and environmental conditions.
Adult head lice typically take a blood meal every 4–6 hours while the host is awake, resulting in several bites throughout the day. Nymphs (immature lice) feed less frequently, generally every 6–8 hours, because their metabolic demand is lower. Body lice, which inhabit clothing rather than hair, feed every 2–3 days, reflecting their adaptation to a different habitat and the longer intervals between host contact.
Factors that modify feeding frequency include:
- Temperature: Warm ambient conditions increase metabolic rate, shortening the time between meals.
- Host activity: Frequent movement or sweating may stimulate lice to feed more often.
- Nutritional status of the host: Higher blood flow to the scalp can encourage more frequent feeding.
- Crowding: Dense infestations create competition, sometimes prompting individuals to feed sooner.
Signs of repeated feeding are:
- Small, pinpoint red spots on the scalp or neck.
- Itching that intensifies several hours after a meal.
- Presence of visible lice or nits near the bite sites.
In controlled laboratory studies, adult head lice survived without a blood meal for up to 72 hours, confirming that they can endure short periods without feeding but are programmed to seek blood multiple times daily under normal conditions. Consequently, a typical infestation results in dozens of bite incidents per week, with the exact count dependent on the variables listed above.