Who do lice not eat? - briefly
Lice feed exclusively on the blood of warm‑blooded hosts and do not consume plant matter, other insects, or any non‑blood food sources.
Who do lice not eat? - in detail
Lice are obligate ectoparasites that survive by piercing the skin of their hosts and sucking blood. Their mouthparts are specialized for fluid extraction, not for chewing or grinding, which limits their diet to liquid blood meals from specific warm‑blooded animals.
Consequently, lice do not consume:
- Plant material of any kind, including leaves, stems, pollen, or nectar.
- Fungal spores or mycelium.
- Detritus such as skin flakes, hair, or dead tissue.
- Other arthropods, including insects, mites, or other lice.
- Non‑blood fluids, for example saliva, mucus, or bodily secretions that are not blood.
- Vertebrate tissues that are not vascular, such as muscle or bone.
The restriction to blood is enforced by several physiological factors. Their digestive enzymes are adapted to break down hemoglobin and plasma proteins, while they lack the enzymes required to process carbohydrates, lipids, or chitin. Their gut is short and simple, optimized for rapid absorption of liquid nutrients, and incapable of handling solid particles.
Different species of lice exhibit host specificity, but all share the same feeding limitation. Human head and body lice feed exclusively on human blood; cattle lice feed on bovine blood; pigeon lice feed on avian blood. None of these species expand their diet to include the items listed above, regardless of environmental availability.
In summary, lice’s anatomical and biochemical specialization confines them to a blood‑only diet, excluding all plant matter, fungi, detritus, other animals, and any solid or non‑blood substances.