Why do bedbugs bite only one person and not another? - briefly
Bedbugs target hosts that emit higher levels of body heat, carbon‑dioxide, and specific skin chemicals, making those individuals more prone to bites. Genetic traits and prior exposure can further reduce a person’s attractiveness, resulting in uneven feeding patterns.
Why do bedbugs bite only one person and not another? - in detail
Bedbugs locate a host by sensing carbon‑dioxide, body heat, and volatile compounds released from the skin. Individuals who exhale more CO₂, generate higher surface temperature, or emit larger quantities of certain chemicals become more detectable. Skin secretions contain lactic acid, ammonia, fatty acids, and other metabolites; their concentration varies with genetics, diet, and hygiene. These variations create distinct odor profiles that can attract or repel the insects.
Blood‑type differences influence attraction. Studies indicate that type O blood often elicits a stronger response from blood‑feeding arthropods, while type A may be less appealing. The same principle applies to the composition of the skin microbiome. Bacterial colonies produce additional volatile organic compounds, altering the scent signature that bedbugs use for host selection.
The host’s immune reaction determines whether a bite is noticed. Some people mount a robust histamine response, producing welts and itching that draw attention to the feeding site. Others experience a muted or delayed reaction, allowing multiple bites to go unnoticed. Consequently, the perception that only one person is targeted may stem from differing visibility of the bite marks rather than exclusive feeding.
Environmental conditions shape exposure. A person who sleeps near clutter, cracks, or upholstered furniture provides easier access for the insects. Mattress encasements, elevated bed frames, or frequent laundering reduce the likelihood of contact. Conversely, a sleeper who remains still for extended periods offers a stable target, increasing the chance of being bitten.
Population density of the insects also matters. When a colony is small, individuals may concentrate on the most readily detected host. As numbers rise, competition forces them to expand feeding across multiple occupants, diminishing apparent selectivity.
In summary, the apparent preference for a particular individual results from a combination of physiological cues (CO₂ output, heat, skin odor), blood‑type and microbiome influences, the host’s immune visibility, and the surrounding environment. These factors together determine which person receives bites while others remain apparently untouched.