What do lice do? - briefly
Lice survive by piercing the host’s skin with their mouthparts to consume blood, which leads to itching and possible disease transmission. They lay eggs, called nits, that adhere to hair shafts and hatch quickly, allowing the infestation to spread rapidly.
What do lice do? - in detail
Lice are obligate ectoparasites that survive exclusively on the blood of their hosts. Adult females insert their mouthparts into the skin, pierce capillaries, and ingest small volumes of blood several times a day. This feeding behavior provides the nutrients required for egg production and sustains the entire colony.
Reproduction proceeds rapidly. After a blood meal, a female lays 5–8 eggs (nits) on each hair shaft, cementing them with a proteinaceous glue. Eggs hatch in 7–10 days, releasing nymphs that resemble miniature adults. Nymphs undergo three successive molts, each lasting 2–3 days, before reaching reproductive maturity. Under optimal conditions, a generation can complete its life cycle within three weeks, allowing populations to expand exponentially.
Lice exhibit limited mobility. They crawl rather than fly, using their claws to cling to hair or feathers. Movement is directed toward warm, protected areas of the host’s body where blood flow is abundant. Sensory organs detect temperature gradients and chemical cues, guiding them to suitable feeding sites.
Impact on the host includes:
- Irritation from repeated bites, leading to scratching and possible secondary bacterial infection.
- Localized inflammation caused by saliva enzymes that prevent blood clotting.
- In severe infestations, anemia may develop due to chronic blood loss.
Control strategies target the life cycle stages:
- Mechanical removal of nits with fine-toothed combs.
- Application of topical insecticides that disrupt nerve function in adults and nymphs.
- Use of oral medications that interfere with lice metabolism, reducing egg viability.
Understanding these biological processes enables effective management and prevention of infestations.