What do fleas that parasitize humans feed on? - briefly
Human‑parasitizing fleas obtain nutrition exclusively by piercing the skin and sucking the host’s blood. Their diet consists of the liquid blood meal required for development and reproduction.
What do fleas that parasitize humans feed on? - in detail
Human‑parasitizing fleas, principally the species Pulex irritans and, in some regions, Ctenocephalides spp., obtain nourishment almost exclusively from the host’s blood. Adult females insert their mouthparts into the skin, locate a capillary, and ingest a liquid meal rich in plasma, erythrocytes, and serum proteins. Each blood meal supplies the nutrients required for egg production; a single female can lay 20–30 eggs after one feeding.
The nutritional composition of the ingested blood includes:
- Hemoglobin, providing iron and amino acids.
- Plasma proteins such as albumin and globulins, supporting tissue synthesis.
- Lipids and cholesterol, contributing to energy reserves.
- Glucose and other simple sugars, serving immediate metabolic needs.
Larval stages do not feed directly on the host. After the eggs hatch, larvae reside in the environment, consuming organic debris, shed skin, fungal spores, and the fecal pellets of adult fleas, which contain partially digested blood. This detritus supplies the proteins and lipids necessary for development until pupation.
Adult fleas may take multiple blood meals over their lifespan, typically ranging from two weeks to several months, depending on temperature and host availability. Their feeding frequency is regulated by the size of the blood meal; insufficient intake delays egg maturation, while a full engorgement accelerates reproduction.
In summary, the diet of human‑infesting fleas consists primarily of host blood for adults, delivering a complex mix of proteins, iron, lipids, and carbohydrates essential for reproduction, while immature stages rely on environmental organic matter and processed blood residues.