How does a tick suck blood? - briefly
A tick penetrates the host’s skin with its barbed hypostome, then releases saliva containing anticoagulants to prevent clotting while it draws blood through its mouthparts. The feeding can continue for days as the arthropod gradually engorges.
How does a tick suck blood? - in detail
Ticks attach to a host using their fore‑legs, which locate a suitable spot through sensory organs that detect heat, carbon dioxide, and movement. Once a site is chosen, the tick inserts its hypostome—a barbed, pencil‑like structure—into the skin. The hypostome’s tiny backward‑pointing teeth anchor the parasite, preventing removal while the tick feeds.
Saliva is injected simultaneously. It contains anticoagulants (such as apyrase and tick‑derived factor Xa inhibitors) that block clot formation, vasodilators that widen blood vessels, and immunomodulatory proteins that suppress the host’s inflammatory response. These compounds maintain a steady flow of blood and reduce detection by the host’s immune system.
A flexible canal called the pharyngeal tube runs from the hypostome to the tick’s midgut. Blood enters this tube by capillary action and is drawn into the gut through a series of muscular contractions. The tick’s gut epithelium expands dramatically, allowing the insect to store many times its body weight in blood. During engorgement, the tick’s exoskeleton stretches, and the abdomen can increase in volume up to 100‑fold.
Key physiological steps:
- Attachment: hypostome insertion and anchoring via barbs.
- Salivation: delivery of anticoagulant and anti‑inflammatory agents.
- Ingestion: blood drawn through the pharyngeal canal into the midgut.
- Storage: gut expansion and concentration of nutrients.
- Detachment: after completing the meal, the tick releases its grip and drops off the host.
The entire process can last from several hours to several days, depending on the tick species and developmental stage. Throughout feeding, the tick continuously secretes saliva to keep the blood fluid and to evade host defenses, ensuring efficient nutrient acquisition.