Why do bedbugs bite selectively? - briefly
Bedbugs preferentially target hosts that emit higher concentrations of carbon dioxide and specific skin‑odor compounds, which differ among individuals. Their chemosensory receptors detect these cues, resulting in selective feeding.
Why do bedbugs bite selectively? - in detail
Bedbugs exhibit a pronounced preference for certain hosts, a behavior that results from the integration of sensory, physiological, and genetic mechanisms.
The initial stage of host selection relies on the detection of thermal cues, carbon‑dioxide plumes, and specific skin‑derived chemicals. Heat emitted by a warm‑blooded animal creates a gradient that guides the insect toward potential victims. Carbon‑dioxide, released through respiration, functions as a long‑range attractant, while volatile compounds such as fatty acids, lactic acid, and ammonia serve as short‑range signals that differentiate among individuals.
Following detection, the decision to feed depends on several internal and external factors:
- Blood composition: higher protein and iron concentrations increase the nutritional value of a meal, prompting the insect to favor hosts with richer blood.
- Host immune response: individuals whose blood contains elevated levels of anti‑coagulants or immune‑modulating proteins may deter feeding, as the insect experiences prolonged engorgement times or reduced blood intake.
- Prior feeding history: after a blood meal, bedbugs enter a quiescent phase lasting several days to weeks; during this period, the drive to locate a new host diminishes, influencing the pattern of bites across a population.
Physiologically, the insect’s digestive system imposes limits on the volume of blood that can be processed at one time. The midgut expands to accommodate the meal, and enzymatic activity peaks during the first 24 hours, after which digestion slows. Overloading the gut leads to increased mortality, reinforcing selective feeding.
Genetic variation among populations contributes to differential host preferences. Strains adapted to specific environments—such as urban apartments versus rural dwellings—display distinct expression levels of chemosensory receptors, altering their responsiveness to particular kairomones.
Understanding these mechanisms informs pest‑management strategies. Targeting the sensory pathways with synthetic attractants can improve trap efficacy, while manipulating host factors—such as using repellents that mask volatile cues—reduces the likelihood of bites. Comprehensive control programs benefit from integrating knowledge of host selection processes with environmental sanitation and chemical treatments.