What do lice look like and how do they move? - briefly
Lice are tiny, wingless insects measuring about 2–4 mm, with a flattened, oval body, six legs, a head equipped with compound eyes and short antennae, and a reddish‑brown coloration. They move by rapid, jerky crawling, using their legs to grasp and traverse hair shafts or fabric fibers.
What do lice look like and how do they move? - in detail
Lice are small, wing‑less insects that belong to the order Phthiraptera. Adult bodies measure 2–4 mm in length, with a flattened, dorsoventrally compressed shape that facilitates movement through hair or feathers. The exoskeleton is a tough, translucent cuticle often tinged brown or gray, allowing the parasite to blend with the host’s coloration. Six legs end in clawed tarsi, each bearing one or two sharp hooks that grip individual strands of hair or feather barbules. Antennae are short, composed of three segments, and bear sensory receptors for chemical and tactile cues. Compound eyes are reduced, providing limited visual input; instead, lice rely on mechanoreceptors and chemoreceptors located on the antennae and legs. Mouthparts form a piercing‑sucking stylet adapted for feeding on blood or skin secretions.
Locomotion relies on coordinated leg movements and the anchoring ability of the claws. Typical motion patterns include:
- Rapid, zig‑zag crawling along a single hair shaft, achieved by alternating the left‑right leg pairs.
- Jumping between adjacent hairs, generated by sudden extension of the hind legs and release of stored elastic energy.
- Climbing vertically against gravity, facilitated by the strong grip of the tarsal hooks and the body’s low center of mass.
Movement speed averages 0.5 mm s⁻¹, sufficient to traverse a host’s head within minutes. When disturbed, lice may detach quickly, dropping to the ground or clinging to nearby surfaces using all six legs. Their ability to navigate dense hair or feather matrices enables continuous access to feeding sites and avoidance of host grooming behaviors. «Lice are ectoparasites that depend on their host’s integument for both shelter and nutrition».