Why do bed bugs bite people? - briefly
Bed bugs pierce skin to obtain blood, which supplies proteins and nutrients required for egg production. Feeding is activated by host‑generated heat and carbon dioxide («heat and carbon dioxide»).
Why do bed bugs bite people? - in detail
Bed bugs (Cimex lectularius) bite humans because they require blood to complete their reproductive cycle. Female insects develop eggs only after a successful blood meal, and each adult needs multiple meals throughout its lifespan. The feeding process is driven by several physiological and behavioral mechanisms.
The insects locate a host by detecting carbon‑dioxide, body heat, and specific skin odors. Once on the skin, they insert a slender, needle‑like proboscis through the epidermis. Saliva injected during the bite contains anticoagulants, anesthetic compounds, and enzymes that prevent clotting and reduce the host’s immediate sensation of pain. These substances facilitate prolonged feeding, allowing the bug to ingest up to 5 µl of blood in a single session lasting 5–10 minutes.
Key reasons for the blood‑feeding habit include:
- Reproduction: nutrient‑rich blood supplies the proteins and lipids needed for egg development.
- Growth: nymphal stages require several meals before each molt.
- Survival: blood provides energy for metabolism and movement.
The bite itself does not transmit pathogens in most cases, but the immune response to saliva can cause erythematous, pruritic welts. Repeated exposure may lead to sensitization, resulting in larger reactions. Secondary bacterial infection can occur if the skin is scratched excessively.
Environmental factors such as darkness, proximity to sleeping areas, and the presence of clutter increase the likelihood of contact. Understanding these biological imperatives clarifies why humans serve as primary hosts for this hematophagous pest.