How do lice cling to hair? - briefly
Lice secure themselves to strands using curved claw‑like tarsal hooks that interlock with the hair cuticle, complemented by a proteinaceous secretion that hardens into a thin, glue‑like film. This combination provides a firm, lasting grip despite movement.
How do lice cling to hair? - in detail
Lice remain attached to a host’s hair through a combination of anatomical adaptations and secreted substances. Their three‑toed claws at the tip of each leg interlock with the cuticle of individual hair shafts. The claws are curved and tapered, allowing them to grip the cylindrical surface securely, even when the hair moves. The arrangement of the claws—two on one side and one on the opposite—creates a stable tripod that resists displacement by friction and tension.
In addition to mechanical grip, lice produce a thin layer of lipid‑rich secretion from specialized glands on the thorax. This waxy coating coats the claws and the surrounding leg segments, increasing surface adhesion and reducing slippage on the hair’s smooth surface. The secretion also helps maintain moisture balance, preventing desiccation while the insect clings.
The body shape contributes to stability. The dorsoventral flattening of the insect lowers its center of gravity, while the ventral thorax bears the legs in a forward‑leaning posture that presses the claws into the hair. This posture distributes the insect’s weight evenly across multiple attachment points, allowing it to remain motionless for extended periods.
Behavioral factors reinforce attachment. After hatching, nymphs immediately seek a hair shaft and use rapid, coordinated leg movements to locate a suitable grip. Once attached, they periodically reposition themselves, tightening the claw hold and renewing the adhesive secretion to compensate for hair growth or host grooming.
Key points of the attachment mechanism:
- Curved, three‑toed claws that interlock with hair cuticle.
- Lipid‑based secretion enhancing grip and preventing drying.
- Flattened body and forward‑leaning leg orientation for weight distribution.
- Continuous repositioning to maintain optimal contact.
These combined features enable lice to stay firmly attached to hair despite host movement, washing, and environmental changes.