How do lice drink blood? - briefly
Lice insert their needle‑like mandibles into the host’s skin, creating a tiny wound, then draw blood through a muscular pharynx that functions as a pump. The ingested fluid passes into a dorsal gut where it is stored until digestion.
How do lice drink blood? - in detail
Lice obtain nourishment by piercing the host’s skin with a specialized mouthpart called the stylet. The stylet consists of a pair of slender, needle‑like structures that can penetrate the epidermis and reach capillary vessels. Once the capillary is accessed, the insect inserts a second, broader tube—the food canal—through which liquid blood flows into the digestive tract.
The feeding cycle proceeds as follows:
- Attachment – The louse clings to hair or feathers with its claws, positioning its head near a suitable blood vessel.
- Penetration – Muscular action drives the stylets forward, cutting through the epidermal layers without causing immediate pain.
- Secretion – Salivary glands release anticoagulant proteins (e.g., apyrase) that prevent clot formation, allowing continuous flow.
- Ingestion – Negative pressure generated by the louse’s pharyngeal muscles draws blood up the food canal.
- Storage – Blood is temporarily held in the midgut, where digestive enzymes break down hemoglobin and other nutrients.
- Detachment – After a brief feeding period, the stylets are withdrawn and the louse resumes a resting position.
The entire process lasts from a few minutes to half an hour, depending on the species and host condition. Lice lack a crop or specialized storage organ; the ingested blood is processed directly in the midgut, and excess fluid is excreted as watery waste. This efficient mechanism enables the parasite to sustain rapid population growth on a single host.