What are the bedbugs that smell?

What are the bedbugs that smell? - briefly

The insect commonly called a bedbug (Cimex lectularius) emits a sweet, musty odor from its scent glands when it is disturbed or crushed. This smell helps identify infestations and distinguishes the species from other pests.

What are the bedbugs that smell? - in detail

Bed bugs, primarily the species Cimex lectularius and Cimex hemipterus, emit a distinctive odor when disturbed. The scent serves as a defensive alarm pheromone that alerts nearby conspecifics and deters predators.

The odor consists of a blend of volatile compounds, including:

  • trans‑2‑hexenal (sharp, leafy note)
  • (E)-2‑octenal (fatty, citrus‑like)
  • 4‑oxo‑2‑hexenal (metallic)
  • 2‑methyloctyl acetate (sweet, fruity)

These chemicals are released from abdominal glands and become detectable within seconds of mechanical stimulation.

Release occurs under three common conditions:

  1. Physical pressure such as crushing or pinching.
  2. Threatened behavior, for example when a host brushes against the insect.
  3. During or immediately after a blood meal, when the bug is vulnerable.

Human perception of the scent varies; most people describe it as a sweet, musty, or coriander‑like smell. Trained detection dogs can identify the odor at concentrations as low as 10 µg m⁻³, making them effective tools for locating hidden infestations.

For pest‑management professionals, the presence of the odor indicates an active population and can guide targeted interventions. Monitoring devices that capture volatile emissions provide early warning, allowing treatment before populations reach damaging levels.