How does a bed bug drink blood? - briefly
A bed bug inserts its needle‑like proboscis into the host’s skin, injects saliva that prevents clotting, and then draws the liquefied blood through its tube‑shaped mouthparts. The meal is held in an expanded abdomen for gradual digestion over several days.
How does a bed bug drink blood? - in detail
Bed bugs obtain nourishment by piercing the skin of their host and siphoning blood through a highly specialized feeding apparatus. The process begins when the insect detects heat and carbon‑dioxide emitted by a sleeping person, guiding it to an optimal attachment site. The insect then anchors itself with its flattened dorsal surface and deploys a pair of elongated, needle‑like mouthparts called stylets.
The stylet bundle consists of:
- Two solid mandibular stylets that act as a saw, cutting through the epidermis and dermis.
- Two hollow maxillary stylets that form a channel for fluid uptake.
- A labial sheath that encases the stylets, protecting them and providing a conduit for saliva.
After the cuticle is breached, the maxillary stylets converge to create a narrow lumen. The bug injects saliva containing anticoagulants (e.g., apyrase) and vasodilators, preventing clot formation and expanding capillaries to facilitate flow. Simultaneously, a negative pressure generated by the contraction of the insect’s cibarial pump draws blood upward through the lumen.
Blood travels from the host into the bug’s foregut, where it is stored temporarily. The insect then regurgitates excess fluid, concentrating the ingested blood and reducing its weight before retreating. Digestion commences in the midgut, where proteolytic enzymes break down hemoglobin and other proteins, while waste products are excreted as dark, liquid feces.
Key stages of the feeding cycle:
- Host detection via thermal and chemical cues.
- Attachment and insertion of stylet bundle.
- Saliva injection to inhibit clotting.
- Negative pressure suction of blood.
- Temporary storage and subsequent digestion.
The entire episode typically lasts from five to ten minutes, after which the bug withdraws its mouthparts, seals the wound with a thin layer of saliva, and returns to its hiding place to digest the meal over several days. This precise combination of anatomical adaptations and biochemical agents enables efficient blood extraction without immediate detection by the host.