What do head lice eat? - briefly
Head lice obtain nourishment by piercing the scalp and drinking human blood. Their diet consists exclusively of this blood, supplying the proteins and nutrients required for growth.
What do head lice eat? - in detail
Head lice are obligate ectoparasites that survive by extracting blood from the human scalp. Their mouthparts form a tiny, serrated tube capable of piercing the epidermis and accessing capillary blood. Saliva injected during feeding contains anticoagulant compounds that keep the blood fluid while the louse ingests it.
Feeding occurs several times each day; an adult louse typically takes a meal lasting 30–60 minutes. Each bite yields approximately 0.5–1 µl of blood, providing the protein, iron, and other nutrients required for growth and reproduction. Nymphs (juvenile lice) follow the same pattern, consuming proportionally smaller volumes as they develop.
Key aspects of the diet include:
- Source: human scalp blood only; no other tissues or substances are utilized.
- Frequency: 4–6 feeding bouts per 24‑hour period.
- Quantity: total daily intake ranges from 2–4 µl per adult, sufficient to sustain metabolic needs.
- Nutrient profile: high‑protein hemoglobin, iron, and trace minerals support egg production and molting.
The continuous removal of blood can cause localized irritation, leading to pruritus and secondary skin lesions. In severe infestations, cumulative blood loss may become measurable, especially in children with high parasite loads.