Hematophagous

Hematophagous, from Greek haima for blood and phagein for to eat, describes organisms that obtain nourishment by feeding on blood. The behavior occurs in a wide range of taxa, including insects such as mosquitoes, fleas, bed bugs, and ticks; vertebrates such as vampire bats; and some parasites among fishes and worms, including parasitic lampreys and certain hookworms. Hematophagy can be obligatory, in which the organism relies on blood for survival, or facultative, in which blood meals supplement other food sources.

Feeding typically involves specialized mouthparts or structures to pierce the host and access blood, and saliva containing anticoagulants, vasodilators, and analgesics to counteract host defenses and facilitate feeding. Examples include the mosquito’s proboscis, the tick’s attachment structures that anchor to the skin, leeches secreting hirudin, and vampire bats delivering saliva rich in anticoagulants and other pharmacologically active compounds.

Ecological and medical significance: hematophagous species are important components of food webs and often serve as vectors for pathogens. They transmit a range of diseases, such as malaria and dengue by mosquitoes, Lyme disease and other tick-borne illnesses, sleeping sickness by tsetse flies, and plague vectors via fleas. Some internal parasites, like hookworms, feed on host blood within the gastrointestinal tract and can cause anemia.

Evolutionary note: blood-feeding has evolved independently in multiple lineages, producing convergent adaptations in mouthparts, saliva composition, and heme digestion. These adaptations influence host–parasite interactions and have implications for disease control and pharmacology.