What does a flea that parasitizes humans feed on? - briefly
Human‑biting fleas obtain nourishment exclusively by sucking the host’s blood from skin capillaries. Their diet consists solely of blood, without ingestion of tissue or other substances.
What does a flea that parasitizes humans feed on? - in detail
Human‑parasitizing fleas obtain nutrition exclusively from the blood of their hosts. The adult stage inserts its mouthparts into the skin, pierces capillaries, and draws a liquid meal that supplies all essential nutrients.
The blood provides:
- Proteins and amino acids required for egg production and tissue maintenance.
- Lipids that serve as energy reserves and are incorporated into developing embryos.
- Carbohydrates in the form of glucose, supporting immediate metabolic needs.
- Minerals such as iron and calcium, crucial for enzymatic functions and cuticle formation.
Feeding behavior varies with species. The human flea (Pulex irritans) and the cat flea (Ctenocephalides felis) are the most common human‑biting vectors. Both exhibit:
- Rapid ingestion – an adult consumes approximately 0.5 µL of blood per bout, completing the meal within 1–2 minutes.
- Multiple feedings – females may blood‑feed every 24–48 hours to sustain egg development; males feed less frequently.
- Selective host choice – attracted by body heat, carbon‑dioxide, and volatile skin compounds, but will feed on any warm‑blooded mammal when preferred hosts are unavailable.
Digestive physiology includes:
- Anticoagulant secretion from salivary glands to prevent clotting, ensuring fluid flow.
- Midgut enzymes that break down hemoglobin and plasma proteins into absorbable peptides.
- Excretion of excess water via Malpighian tubules, concentrating the nutrient load.
Larval stages do not blood‑feed. They rely on organic debris, desiccated adult feces (rich in partially digested blood), and fungal spores within the environment. Adult females deposit eggs on the host or nearby bedding; the resulting larvae develop in the surrounding substrate, completing the life cycle.
In summary, the adult flea that parasitizes humans extracts a complete blood meal that delivers proteins, lipids, carbohydrates, and minerals necessary for reproduction and survival, while its larvae depend on environmental organic matter derived from the adult’s excretions.