Why do bed bugs bite some people more than others? - briefly
Variations in skin chemistry, blood type, and immune response affect how often individuals are targeted, with higher emissions of carbon dioxide and specific fatty acids attracting more bites. Genetic differences that shape skin microbiota also make certain hosts more appealing to the insects.
Why do bed bugs bite some people more than others? - in detail
Bed‑bug feeding patterns are not uniform; individual hosts experience markedly different bite frequencies. Several physiological and biochemical factors influence this disparity.
- Skin surface chemicals – Sweat contains fatty acids, lactic acid, and ammonia. Higher concentrations of these compounds attract hematophagous insects, increasing bite incidence on certain people.
- Blood type – Laboratory tests show that type O blood emits stronger olfactory cues than type A or B, leading to more frequent probing.
- Body temperature and carbon‑dioxide output – Elevated skin temperature and higher respiration rates generate stronger thermal and gaseous gradients, which bed bugs track to locate hosts.
- Microbiome composition – Skin‑resident bacteria metabolise secretions into volatile organic compounds; specific microbial profiles amplify attractant signals.
- Immune response – Some individuals develop pronounced erythema and swelling, producing additional chemical signals that may draw further insects to the same site.
- Genetic predisposition – Polymorphisms in odor‑receptor genes affect perception of host cues, altering susceptibility to bites.
- Previous exposure – Repeated feeding on a host can condition insects to recognize that host’s unique chemical signature, reinforcing feeding preference.
Research using controlled chambers confirms that the combination of these variables predicts bite distribution more accurately than any single factor. Experiments that altered skin pH or masked carbon‑dioxide emissions reduced feeding events by up to 70 %, demonstrating the relative weight of each cue.
Understanding the interplay of chemical attractants, physiological signals, and host genetics explains why some people become preferred targets while others receive few or no bites.