How do bedbugs recognize humans? - briefly
They detect a host by sensing body heat, carbon‑dioxide and skin‑derived volatile compounds, then confirm contact with tactile cues from their antennae. Once these signals are combined, they initiate feeding behavior.
How do bedbugs recognize humans? - in detail
Bedbugs locate a living host through a combination of thermal, chemical, and mechanical signals.
Thermal detection relies on specialized receptors in the antennae and tarsi that respond to temperature gradients. The insects are attracted to temperatures close to human body heat (approximately 34–37 °C).
Chemical detection involves several odorant receptors tuned to volatile compounds emitted by people. Key attractants include carbon dioxide, lactic acid, ammonia, fatty acids, and skin‐derived aldehydes. Carbon dioxide is sensed by maxillary palps, while the other volatiles are perceived by sensilla on the antennae.
Mechanical cues such as vibrations caused by movement or breathing aid in fine‑scale localization. Bedbugs can sense minute substrate vibrations, allowing them to track a host even in low‑light conditions where visual cues are minimal.
Integration of these inputs occurs in the central nervous system, where the signals are weighted to produce a directed movement toward the source. The resulting behavior comprises a series of short, exploratory walks interrupted by pauses for sensory sampling.
Typical sequence of host‑seeking actions:
- Detection of elevated CO₂ levels → activation of maxillary palp receptors.
- Recognition of heat gradient → stimulation of thermoreceptors.
- Identification of skin volatiles → engagement of antennal odorant receptors.
- Response to substrate vibrations → activation of mechanoreceptors.
- Orientation and locomotion toward the combined stimulus source.
The synergy of these sensory modalities enables bedbugs to identify and approach human hosts with high efficiency, ensuring successful blood feeding.