Why do bedbugs attack? - briefly
Bedbugs bite to obtain a blood meal essential for growth and reproduction, with host heat, carbon dioxide, and movement acting as primary cues. The ingested blood supplies nutrients required for egg development.
Why do bedbugs attack? - in detail
Bedbugs initiate feeding when they detect a suitable host. The process relies on a combination of sensory inputs and physiological needs.
The primary drivers are:
- Thermal cues – body heat signals the presence of a warm‑blooded organism. Bedbugs possess thermoreceptors that register temperature gradients as low as 0.5 °C, directing them toward the heat source.
- Carbon‑dioxide emission – exhaled CO₂ creates a plume that the insects follow. Their chemoreceptors are highly sensitive to concentrations typical of human respiration, enabling detection from several meters away.
- Odorant compounds – skin secretions, sweat, and bacterial metabolites contain volatile chemicals such as lactic acid, ammonia, and fatty acids. These act as attractants, enhancing host localization after thermal and CO₂ cues have been identified.
- Vibrational signals – movement of a sleeping host generates minute vibrations transmitted through fabrics and bedding. Bedbugs respond to these mechanical stimuli, confirming the host’s proximity.
Once a host is located, the insect’s feeding behavior is triggered by internal hunger signals. After a period of starvation—typically 5–10 days for adult females—energy reserves decline, prompting aggressive search activity. The need for blood is linked to reproduction: a single blood meal provides the proteins and lipids required for egg development. Female bedbugs can produce up to 200 eggs after one engorgement, creating a strong selective pressure for efficient blood acquisition.
Environmental factors modulate attack frequency:
- Temperature – ambient temperatures between 24 °C and 30 °C accelerate metabolism, shortening the interval between meals.
- Light cycles – bedbugs are nocturnal; darkness reduces host awareness and lowers the risk of disturbance, increasing feeding success.
- Crowding – high population density intensifies competition for blood, leading to more frequent host contacts.
The combination of precise sensory detection, physiological hunger, reproductive demand, and favorable environmental conditions explains why bedbugs actively seek and bite human hosts.