Why does a bedbug land on a person? - briefly
Bedbugs respond to the carbon‑dioxide, warmth, and specific skin odor chemicals that humans emit. Detecting these signals prompts them to climb onto a host in order to obtain a blood meal.
Why does a bedbug land on a person? - in detail
Bed bugs are attracted to humans primarily through chemical and thermal cues. The insects detect carbon dioxide exhaled by a host, which rises in concentration when a person breathes. Simultaneously, they sense body heat, which creates a temperature gradient that guides them toward the source. Skin emanations, such as lactic acid, ammonia, and fatty acids, further enhance the attraction, allowing the bug to locate a suitable feeding site.
When a bed bug reaches a person, it lands to initiate a blood meal. The insect’s mouthparts, called a proboscis, pierce the skin and inject a small amount of anticoagulant saliva. This saliva prevents clotting and numbs the area, enabling the bug to feed for several minutes without detection. After engorgement, the bug retreats to a concealed harbor, such as a mattress seam or furniture crevice, to digest the blood and reproduce.
Factors influencing landing behavior include:
- Host activity level – movement creates air currents that carry carbon dioxide and heat, drawing the insect closer.
- Environmental temperature – warmer rooms increase the bug’s metabolic rate, prompting more frequent host seeking.
- Light conditions – bed bugs are nocturnal; low light reduces visual disturbance, encouraging landing.
- Presence of competing hosts – higher density of people raises carbon dioxide levels, intensifying attraction.
Understanding these mechanisms helps in designing control measures. Reducing carbon dioxide buildup (e.g., improving ventilation), decreasing skin odor exposure (e.g., regular washing), and eliminating harborages disrupt the bug’s ability to locate and land on a human target.