Why do bedbugs bite only some people? - briefly
Bedbugs are drawn to carbon‑dioxide output, body heat, and specific skin chemicals, which vary among individuals; those who emit stronger or more attractive cues are more likely to be selected for feeding. Additionally, differences in immune response can make some people’s skin react visibly to the bite, while others show little or no reaction.
Why do bedbugs bite only some people? - in detail
Bedbugs do not feed indiscriminately; they exhibit a preference for certain hosts based on a combination of physiological and biochemical signals. The insects locate potential victims through heat, carbon‑dioxide, and movement, but the decision to bite depends on additional cues that vary among individuals.
Key determinants of selective feeding include:
- Skin microbiota – Bacterial species that colonize the epidermis emit volatile compounds. Some profiles produce attractants that increase the likelihood of a bite, while others generate deterrents.
- Blood group antigens – Research indicates that individuals with type O blood are more frequently targeted than those with type A or B, suggesting that surface antigens influence host attractiveness.
- Body temperature and perspiration – Higher skin temperature and sweat composition raise the concentration of lactic acid and other metabolites that bedbugs detect as feeding cues.
- Immune response – People with strong inflammatory reactions may experience more noticeable bites, leading to a perception of higher susceptibility, whereas those with muted responses may remain unaware of feeding events.
- Previous exposure – Repeated contact can condition bedbugs to favor a particular host, reinforcing feeding patterns over time.
- Genetic factors – Variations in genes that affect skin chemistry and odor production can create individual differences in attractiveness.
The feeding mechanism itself involves the insect inserting its proboscis into the skin, injecting saliva that contains anticoagulants and anesthetics. The composition of this saliva interacts with the host’s immune system, producing the characteristic wheal and itch. Individuals whose immune systems react more intensely to the salivary proteins report stronger bite reactions, which can be misinterpreted as being more frequently bitten.
In summary, selective biting results from an interplay of microbial odors, blood type, thermal cues, immune reactivity, prior exposure, and genetic makeup. Each factor contributes to the probability that a bedbug will choose one person over another during a feeding episode.