How do bed bugs bite? - briefly
Bed bugs pierce the skin with elongated mouthparts called stylets, inject saliva that contains anticoagulants and anesthetic compounds, and then draw blood from the puncture site. The bite typically leaves a small, red, itchy wel‑whelm that may appear several hours after feeding.
How do bed bugs bite? - in detail
Bed bugs obtain nutrition by piercing the skin with specialized mouthparts called stylets. The elongated maxillae and mandibles form a narrow tube that penetrates the epidermis and reaches a capillary. Saliva, injected simultaneously, contains anticoagulants, vasodilators, and anesthetic compounds that prevent blood clotting, widen the vessel, and mask the sensation of the bite. Blood flows into the insect’s foregut, where it is stored in a distended abdomen that can expand up to ten times its original size after a single feeding session.
The feeding sequence proceeds as follows:
- Location selection: The insect detects heat, carbon‑dioxide, and body odors to identify a suitable site.
- Insertion: Stylets are driven into the skin at an angle of 30–45°, creating a channel approximately 0.2 mm in diameter.
- Saliva delivery: Minute droplets of saliva are released, inhibiting platelet aggregation and dilating the blood vessel.
- Blood uptake: Negative pressure generated by the cibarial pump draws blood into the foregut; ingestion rates average 0.05 µL per minute.
- Retraction: After engorgement, the mouthparts are withdrawn, leaving a puncture that often heals without a visible mark.
The bite itself typically appears as a small, red, raised papule. Because the anesthetic component of the saliva reduces immediate pain, the reaction may be delayed 12–48 hours, when the immune system responds to foreign proteins. The severity of the skin reaction varies with individual sensitivity, the number of feeding events, and the quantity of saliva injected.
Factors influencing feeding efficiency include ambient temperature (optimal range 22–30 °C), humidity (40–80 % relative humidity), and the host’s blood flow. Bed bugs can feed for 5–10 minutes, consuming 1–5 µL of blood per session, and may repeat the process multiple times during a night.
Understanding this mechanism is essential for diagnosing bites, designing effective control measures, and developing repellents that interfere with host detection or saliva activity.