What attracts bedbugs to humans? - briefly
Bedbugs locate humans by sensing carbon dioxide, body heat, and skin‑derived chemicals such as lactic acid, fatty acids, and specific pheromones. These cues direct them to a blood meal.
What attracts bedbugs to humans? - in detail
Bedbugs locate a host by sensing a combination of chemical, thermal, and physical cues emitted by people. Their sensory apparatus includes antennae and maxillary palps equipped with receptors that respond to volatile substances and temperature gradients.
Carbon dioxide is the primary indicator of a living host. Exhaled air creates a plume that bedbugs follow through chemotaxis. The insects can detect concentrations as low as 0.01 % CO₂, allowing them to orient toward a breathing person even in darkness.
Heat emanating from the body provides a secondary signal. Bedbugs possess thermoreceptors that register temperature differences of 0.1 °C. A warm surface (typically 30–34 °C) triggers activation and guides the insect to the skin.
Skin secretions generate a complex blend of volatile organic compounds (VOCs). Key components include:
- Lactic acid
- Ammonia
- Fatty acids (e.g., isovaleric acid)
- Aldehydes and ketones
- Bacterial metabolites from the resident microbiota
These chemicals act as kairomones, attracting bedbugs from several meters away. The specific composition varies among individuals, influencing the degree of attraction.
Movement generates subtle air currents that enhance the CO₂ and heat signals. Bedbugs respond to these mechanical cues by increasing locomotor activity and orienting toward the source.
Sensory integration occurs in the central nervous system, where inputs from CO₂ receptors, thermoreceptors, and chemoreceptors are weighted to produce a directed response. Nymphs rely more heavily on chemical cues, while adults combine all three modalities for efficient host location.
Understanding these attractants informs control strategies, such as traps that emit CO₂, heat, or synthetic VOC blends to lure and capture the insects.