What do lice eat? - briefly
Lice are obligate ectoparasites that obtain nutrition by piercing the skin of humans or animals and sucking the resulting blood.
What do lice eat? - in detail
Lice are obligate ectoparasites that survive exclusively on the blood of their specific hosts. Their mouthparts, formed as stylets, pierce the epidermis to access capillary blood. Each feeding episode extracts a minute volume, typically 0.5–1 µL, sufficient to sustain metabolism and reproduction. Feeding frequency varies among species:
- Head lice (Pediculus humanus capitis): feed every 3–4 hours while the host is awake; each adult consumes approximately 0.8 µL per meal.
- Body lice (Pediculus humanus corporis): feed at similar intervals but can remain longer on clothing, allowing intermittent access to the host.
- Pubic lice (Pthirus pubis): feed every 4–5 hours; each bite delivers about 0.6 µL of blood.
Blood provides the sole source of protein, lipids, carbohydrates, and essential micronutrients. Lice lack digestive enzymes for solid food; the ingested plasma is rapidly assimilated, while erythrocytes are broken down for hemoglobin-derived amino acids. The gut stores only a short‑term reserve, necessitating continuous feeding to maintain energy balance.
Reproductive output correlates directly with blood intake. An adult female head louse, after a series of meals, can lay up to 8 eggs per day, each egg containing sufficient yolk derived from host blood. Nutrient limitation slows oviposition and reduces hatchability.
Environmental conditions influence feeding behavior. Elevated temperatures increase metabolic rate, prompting more frequent blood meals, whereas low humidity can reduce feeding efficiency due to cuticular water loss.
In summary, lice subsist on repeated, small blood meals obtained via specialized stylet mouthparts; the volume and frequency of ingestion support survival, growth, and prolific reproduction across all human‑associated species.