What do fleas and lice feed on? - briefly
Both fleas and lice are obligate hematophages that obtain nutrition by sucking the blood of their hosts. Fleas infest mammals and birds, whereas lice specialize on humans or other mammals, feeding on blood at the skin or hair surface.
What do fleas and lice feed on? - in detail
Fleas obtain nutrition exclusively from the blood of their hosts. Adult females require a blood meal before each oviposition cycle; the protein and lipid content of the ingested plasma support egg development. Blood is drawn through a serrated stylet that pierces the epidermis, bypassing clotting mechanisms by injecting anticoagulant saliva. Flea larvae, which reside in the host’s nest or environment, feed on a mixture of adult feces (rich in partially digested blood), desiccated adult carcasses, and organic debris. This diet supplies the amino acids and fatty acids essential for metamorphosis into the adult stage.
Lice exhibit two feeding strategies, depending on the suborder. Sucking lice (Anoplura) pierce the skin and consume whole blood, similar to fleas, but they insert a single tube-like mouthpart that extracts blood directly from capillaries. Their feeding frequency is high; individuals may take several meals per day, each lasting a few minutes, providing the continuous supply of hemoglobin and plasma proteins needed for rapid growth and reproduction.
Chewing lice (Mallophaga) do not ingest blood. Instead, they scrape and ingest epidermal tissue, skin scales, sebaceous secretions, and, on avian hosts, feather pulp. Their mandibles are adapted for macerating keratinized material, allowing extraction of proteins and lipids from the host’s outer layers. This diet sustains their slower development cycle and supports the production of eggs that are laid directly on the host’s plumage or hair.
Key nutritional aspects for both groups include:
- Protein: essential for egg synthesis and tissue repair.
- Lipids: provide energy for locomotion and development.
- Iron and heme (blood feeders): required for metabolic enzymes.
- Keratin-derived amino acids (chewing lice): obtained from skin and feather fragments.
Host specificity influences dietary composition. Mammalian fleas often prefer rodents, cats, or dogs, matching the host’s blood protein profile, while human fleas (Pulex irritans) adapt to human plasma constituents. Sucking lice are generally restricted to a single mammalian species, reflecting co‑evolution with host blood chemistry. Chewing lice display broader host ranges, exploiting the outer integument of birds, mammals, or reptiles.
In summary, flea nutrition centers on repeated blood meals for adults and fecal‑derived blood for larvae, whereas lice either ingest whole blood (sucking lice) or consume epidermal and keratinous material (chewing lice). Both strategies deliver the macronutrients necessary for growth, reproduction, and survival within the host environment.