What do bed bugs respond to? - briefly
Bed bugs are attracted to body heat, carbon dioxide, human skin odors, and vibrational cues. These signals guide them to a host for feeding.
What do bed bugs respond to? - in detail
Bed bugs locate hosts primarily through a combination of thermal, chemical, and mechanical cues. Their sensory system detects minute temperature differences, elevated carbon‑dioxide concentrations, specific skin volatiles, and substrate vibrations. Each stimulus triggers a distinct behavioral response that guides the insect toward a blood source.
Temperature gradients serve as the most reliable indicator of a warm‑blooded host. Thermoreceptors on the antennae and tarsi respond to temperature increases as low as 0.1 °C above ambient, directing movement toward heat sources. The preferred range is 30–34 °C, matching human skin temperature. Infrared radiation emitted by a host further enhances orientation.
Carbon dioxide acts as a long‑range attractant. Lab studies show that concentrations as low as 0.04 % above background elicit activation, while 0.5 % stimulates sustained locomotion toward the source. Bed bugs possess CO₂‑sensitive sensilla on the maxillary palps that trigger up‑wind flight or crawling.
Skin odor compounds, especially fatty acids, aldehydes, and lactic acid, provide close‑range cues. Odorant receptors on the antennae detect these volatiles, allowing discrimination between human and non‑human hosts. Synthetic blends replicating human scent have been shown to increase capture rates in traps.
Mechanical vibrations transmitted through fabric or bedding stimulate seeking behavior. Vibrissae and chordotonal organs sense minute movements, prompting the insect to move toward the disturbance, which often coincides with a resting host.
Light exposure influences activity patterns. Bed bugs are negatively phototactic; darkness promotes feeding and aggregation, while bright light suppresses movement. This behavior underlies the nocturnal feeding schedule.
Humidity affects survival and activity. Relative humidity above 70 % maintains optimal cuticular water balance, enhancing locomotion and feeding efficiency. Low humidity induces desiccation avoidance, prompting retreat to protected microhabitats.
Pheromonal communication modulates aggregation and mating. The aggregation pheromone (a blend of volatile fatty acids) induces clustering in sheltered areas, increasing the likelihood of encountering a host. Male‑produced sex pheromones trigger female receptivity during courtship.
Collectively, these stimuli form a hierarchical detection system: long‑range cues (CO₂, heat) guide initial approach, medium‑range cues (skin volatiles) refine targeting, and short‑range cues (vibrations, tactile feedback) finalize contact. Understanding each component informs the design of monitoring devices and control strategies, such as heat‑based traps, CO₂ emitters, synthetic odor lures, and darkness‑protected interceptors.