Why do bedbugs sometimes bite only one person? - briefly
Bedbugs are drawn to particular cues—higher body heat, increased carbon‑dioxide emission, and specific skin odors—that differ among individuals. A person producing stronger signals can attract most of the bites while others receive few or none.
Why do bedbugs sometimes bite only one person? - in detail
Bedbugs locate hosts by detecting carbon‑dioxide, body heat, and chemical cues emitted from the skin. Not all occupants emit these signals equally; variations in metabolism, respiration rate, and skin chemistry create distinct attraction profiles. Individuals who exhale more carbon‑dioxide, such as those who are larger, pregnant, or engaged in vigorous activity, generate a stronger plume that guides insects toward them preferentially.
Blood‑type antigens, specifically the presence of certain secretor status proteins, influence the composition of skin secretions. Studies show that people with blood type O or with a secretor phenotype produce higher concentrations of compounds that stimulate the bug’s sensory organs, making them more likely to be targeted.
Temperature gradients on the skin surface differ among people. Localized warmth from fever, inflammation, or simply higher basal body temperature creates a thermal hotspot, drawing bugs to that area while cooler bodies remain relatively ignored.
Previous exposure to bedbug saliva can induce a desensitization effect. Repeated bites may lead to reduced immune response, causing subsequent feedings to be less noticeable or to occur on different hosts. Conversely, individuals with no prior exposure may exhibit stronger inflammatory reactions, making their bites more evident.
Behavioral factors also play a role. People who spend more time in bed, use fewer protective barriers (such as mattress encasements), or have cluttered sleeping environments provide easier access and more hiding places for the insects, concentrating feeding activity on those hosts.
Key determinants:
- Elevated carbon‑dioxide output (larger body size, pregnancy, activity level)
- Specific blood‑type antigens and secretor status influencing skin chemistry
- Higher localized skin temperature (fever, inflammation)
- Lack of prior sensitization to bedbug saliva
- Prolonged or unprotected contact with sleeping areas
These physiological and behavioral variables combine to produce a pattern where bites may appear on a single person while others sharing the same space remain untouched.