Why do bedbugs stink? - briefly
Bedbugs release a pungent odor when threatened by secreting aldehyde‑based compounds from their scent glands, which serve as a chemical defense against predators. The scent is often described as musty, sweet‑smelling, and reminiscent of coriander.
Why do bedbugs stink? - in detail
Bedbugs emit a distinctive odor when disturbed or crushed. The smell originates from specialized scent glands located in the abdomen. These glands release a mixture of volatile compounds that serve both defensive and communicative functions.
The primary components of the secretion include:
- trans‑2‑hexenal, a green‑leaf aldehyde with a sharp, pungent aroma;
- (E)-2‑octenal, contributing a fatty, slightly sweet note;
- (E)-2‑decenal, adding a stronger, oily fragrance;
- 2‑methyltetrahydrofuran, providing a faint, sweet scent;
- various short‑chain fatty acids, such as acetic and butyric acids, which impart a sour, rancid character.
When a bedbug is threatened, the nervous system stimulates the glands to eject the mixture through a tiny opening near the hind end. The release occurs rapidly, creating a cloud that deters predators and signals danger to conspecifics. The odor persists because the compounds are relatively stable and have low vapor pressure, allowing them to linger on surfaces and clothing.
Crushing a bedbug ruptures the glands, causing the same chemicals to disperse uncontrollably. The resulting smell often adheres to fabric, making removal difficult without thorough washing or chemical treatment.
In summary, the offensive odor is a complex blend of aldehydes, ketones, and fatty acids produced by abdominal scent glands, released as a defensive response and as an alarm signal within the species.