How do lice hatch? - briefly
Female lice attach their eggs to hair shafts, where they incubate for roughly 7–10 days at body temperature; the eggs then hatch, releasing nymphs that immediately begin feeding and molting toward adulthood.
How do lice hatch? - in detail
Lice develop from eggs called nits, which are firmly attached to hair shafts by a cement-like secretion. The embryonic stage lasts approximately 7–10 days, depending on temperature and species. During this period the embryo undergoes cellular differentiation, formation of the head, thorax, abdomen, legs, and sensory organs.
When development is complete, the nymph uses a specialized structure called the operculum, a thin cap covering the egg’s opening, to break free. Muscular contractions of the embryo generate pressure against the operculum, causing it to split. The emerging nymph then pushes its head and thorax through the opening, followed by the rest of the body.
Key physiological events at hatching:
- Operculum rupture – enzymatic softening of the cement and mechanical force separate the cap from the egg shell.
- Head emergence – the head, equipped with antennae and mouthparts, leads the exit.
- Body expansion – hemolymph pressure inflates the body, allowing rapid movement out of the shell.
- Cuticle hardening – within minutes, the new exoskeleton sclerotizes, providing protection.
After emergence, the nymph is a miniature adult, lacking full reproductive capability but already capable of feeding on blood. It will molt three times over the next 10–12 days, reaching the adult stage. Environmental factors such as humidity and temperature influence the timing of each step, with higher temperatures accelerating development and lower humidity prolonging the operculum’s dissolution.