How do lice appear and where do they live? - briefly
Lice emerge from eggs (nits) affixed to hair shafts and must feed on the host’s blood to develop. They reside on the scalp, body hair, or clothing, depending on the species, and stay attached to the host until eliminated.
How do lice appear and where do they live? - in detail
Lice originate from eggs laid by adult females on a host’s hair shaft or body hair. Each female deposits 6‑10 eggs per day, attaching them with a cement‑like secretion that hardens within minutes. The eggs, commonly called nits, remain firmly affixed until the embryo matures, a period that lasts 7‑10 days depending on temperature and species. Upon hatching, the newly emerged nymph resembles a miniature adult and undergoes three successive molts over 9‑12 days before reaching reproductive maturity. The entire life cycle—from egg to egg‑laying adult—completes in approximately three weeks under optimal conditions.
Lice inhabit specific niches on their hosts:
- Scalp hair – head lice (Pediculus humanus capitis) remain on the surface of the scalp, feeding on blood several times daily.
- Body hair and clothing seams – body lice (Pediculus humanus corporis) live in the seams of garments, moving to the skin only to feed.
- Pubic region – crab lice (Pthirus pubis) occupy coarse hair of the genital area and occasionally other body hair.
- Animal hosts – various species infest mammals and birds, residing on feathers, fur, or skin depending on the host’s morphology.
Environmental factors that encourage infestation include close personal contact, crowded living conditions, limited access to clean clothing, and temperatures between 28 °C and 32 °C, which accelerate development. Lice cannot survive long off a host; most species die within 48 hours without a blood meal, underscoring their reliance on a living host for sustenance and reproduction.