Why do bedbugs bite people? - briefly
Bedbugs feed on human blood to obtain the protein and nutrients essential for egg production and development. They locate hosts by detecting body heat, carbon dioxide, and skin odors.
Why do bedbugs bite people? - in detail
Bedbugs locate a host by sensing body heat, carbon‑dioxide, and movement. Their antennae contain thermoreceptors that detect temperature gradients, while specialized sensory organs on the tarsi respond to carbon‑dioxide exhaled by mammals. Once a suitable spot is identified, the insect inserts its elongated mouthparts— a stylet composed of a labium and two maxillae—through the skin to reach a blood vessel.
During feeding, the bug injects saliva that contains anticoagulants, vasodilators, and anesthetic proteins. Anticoagulants prevent clotting, allowing continuous blood flow; vasodilators expand capillaries, increasing the volume of accessible blood; anesthetic compounds numb the bite area, so the host often does not feel the intrusion. The saliva also carries enzymes that suppress local immune responses, reducing inflammation while the insect feeds for several minutes.
After engorgement, the insect retracts its stylet and retreats to a hidden harbor—cracks, seams, or furniture. It digests the blood meal over several days, converting proteins into nutrients needed for development and reproduction. The need for repeated meals drives the insect to seek new hosts, explaining why multiple bites may appear in a short period.
Key factors that motivate the feeding behavior include:
- Nutritional requirement: Female bedbugs need a blood meal to produce eggs; males also require blood for survival.
- Host availability: Presence of humans or other warm‑blooded animals provides a reliable source of nutrients.
- Physiological adaptation: Specialized mouthparts and saliva composition enable efficient extraction of blood without immediate detection.
Consequences of the bite are limited to localized skin reactions—red, itchy welts—caused by the immune system responding to salivary proteins. In rare cases, allergic reactions or secondary infections can develop, but the insects do not transmit known diseases. Their attraction to humans is therefore driven by evolutionary adaptations that maximize blood acquisition while minimizing host awareness.