How and whom do bed bugs bite? - briefly
Bed bugs pierce the skin with a needle‑like mouthpart, inject saliva that prevents clotting, and withdraw blood for several minutes. They mainly target exposed areas of humans—such as the face, neck, arms, and hands—but will also feed on other warm‑blooded mammals when available.
How and whom do bed bugs bite? - in detail
Bed bugs locate a host through a combination of heat, carbon‑dioxide, and specific chemical cues emitted by the skin. Their sensory organs detect temperature gradients as low as 0.1 °C above ambient, allowing them to move toward warm bodies. Simultaneously, they sense the rise in carbon‑dioxide that occurs with exhalation; a concentration increase of 0.04 % triggers activation of their antennae. Cutaneous odorants, such as lactic acid, ammonia, and certain fatty acids, further refine host selection, directing the insect to areas where these compounds accumulate.
Feeding occurs after the insect settles on exposed skin. The mouthparts, a modified stylet called a proboscis, penetrate the epidermis without breaking the skin surface. Saliva, rich in anticoagulants and anesthetic proteins, is injected to prevent clotting and to mask the bite, enabling a prolonged blood meal lasting 5–10 minutes. The insect draws approximately 0.5 µL of blood per feeding, a volume sufficient for egg production.
Bed bugs display no strict preference for a particular human demographic. Biting frequency correlates with factors that increase host detectability:
- Body temperature: Individuals with higher skin temperature attract more insects.
- Respiratory output: Persons who exhale more carbon‑dioxide, such as adults, larger children, or those engaged in physical activity, experience higher bite rates.
- Skin chemistry: Variations in sweat composition and microbiome influence attractiveness; higher levels of certain fatty acids and lactic acid can increase bite incidence.
- Blood type: Some studies suggest type O may be marginally more appealing, though evidence is not conclusive.
- Clothing and exposure: Areas of skin uncovered during sleep—face, neck, arms, and hands—are most commonly bitten.
Although any warm‑blooded vertebrate can serve as a source of blood, humans are the primary hosts in domestic infestations. Pets such as dogs and cats may be bitten when they share sleeping areas, but the insect’s feeding preference remains biased toward humans due to their larger body surface and higher carbon‑dioxide output.
In summary, bed bugs locate hosts by detecting heat, carbon‑dioxide, and skin odorants, then insert a proboscis to ingest blood while delivering anesthetic saliva. Their biting pattern is driven by physiological cues rather than age, gender, or ethnicity, with exposure of skin and elevated metabolic signals being the decisive factors.