What do lice feed on in humans? - briefly
Human lice obtain nourishment by piercing the skin and drinking blood from the host’s scalp or body hair follicles. They use specialized mouthparts to ingest plasma and red blood cells directly.
What do lice feed on in humans? - in detail
Lice that infest people survive exclusively on the host’s blood. Adult head and body lice insert a slender, saw‑toothed mandible into the epidermis, pierce a capillary, and draw a minute volume of plasma with each bite. A single feeding episode supplies enough protein and iron to sustain the insect for several days; body lice typically feed every 30–60 minutes, while head lice take longer intervals, often several hours, before the next meal.
The nutritional composition of the ingested fluid is primarily hemoglobin‑derived proteins, glucose, and trace minerals. Saliva injected during probing contains anticoagulants and anesthetic compounds that prevent clotting and reduce host awareness, allowing uninterrupted extraction. After ingestion, the blood is stored in a distended midgut, where proteolytic enzymes break down hemoglobin into amino acids that support egg production and molting.
Feeding sites correspond to the lice’s preferred habitats. Head lice remain on the scalp, attaching near the hair shaft base where the skin is thin. Body lice inhabit clothing seams and move to the skin for brief feedings, usually on the torso, arms, or legs. Pubic lice (Pthirus pubis) target the coarse hair of the genital region, inserting their mouthparts into the adjacent skin.
The feeding cycle drives the reproductive rate. A fertilized female can lay up to 10 eggs per day, each requiring a blood meal for embryonic development. Deprivation of blood for more than 24 hours leads to rapid weight loss, decreased locomotion, and eventual death, underscoring the parasite’s strict dependence on human plasma.
In summary, human‑infesting lice rely on repeated, minute blood extractions from capillaries in the skin, using specialized mouthparts and saliva to obtain the proteins, carbohydrates, and minerals essential for growth, reproduction, and survival.