How do bedbugs sense humans? - briefly
Bedbugs locate hosts by detecting carbon dioxide, body heat, and skin‑derived odor molecules through chemosensory receptors on their antennae and tarsi. They combine these signals to navigate toward a sleeping person.
How do bedbugs sense humans? - in detail
Bedbugs locate a host through a combination of sensory cues that operate simultaneously.
Thermal detection is mediated by specialized receptors on the antennae and maxillary palps. These thermoreceptors respond to temperature gradients as small as 0.1 °C, allowing the insect to move toward the warmth emitted by a sleeping person.
Carbon dioxide is another primary attractant. Receptors in the antennae detect elevated CO₂ concentrations typical of exhaled breath. Sensitivity thresholds lie around 0.5 % CO₂ above ambient levels, triggering directed movement upwind.
Chemical cues, often referred to as kairomones, include volatile compounds found in human skin secretions, sweat, and clothing fibers. Olfactory sensilla on the antennae bind these molecules, producing neural signals that guide the bug toward the source.
Mechanical vibrations, such as those generated by breathing, heartbeats, or movement, are sensed by mechanoreceptors on the legs. The insects can discern frequencies between 10–100 Hz, which correspond to typical human physiological rhythms.
The integration of these signals follows a hierarchical pattern: initial long‑range attraction relies on heat and CO₂ gradients, while short‑range navigation depends on chemical and vibratory cues. Once contact is made, tactile receptors on the mouthparts confirm the presence of suitable feeding tissue.
Key characteristics of the sensory system:
- Antennae and maxillary palps house thermoreceptors, chemoreceptors, and CO₂ detectors.
- Leg sensilla provide mechanosensory input for low‑frequency vibrations.
- Neural pathways converge in the central brain, where signal weighting determines movement direction.
Understanding these mechanisms informs control strategies that disrupt specific cues, such as heat‑based traps, CO₂ generators, or synthetic kairomone lures.