What does a common bed bug look like? - briefly
A common bed bug is a wingless, oval insect about 4–5 mm long, reddish‑brown in color, with a flat dorsal surface that becomes balloon‑shaped after feeding. Its body is segmented, bearing tiny eyespots and short, hair‑like antennae.
What does a common bed bug look like? - in detail
A common bed bug is a small, flat, oval‑shaped insect. Adult specimens measure approximately 4–5 mm in length and 2.5 mm in width, comparable to the size of an apple seed. Their bodies are dorsoventrally flattened, allowing them to hide in narrow cracks and crevices.
The exoskeleton is a matte, reddish‑brown color after feeding; unfed individuals appear lighter, pale brown to tan. The abdomen is segmented, each segment bearing fine hair‑like setae that give a slightly fuzzy appearance under magnification. Six legs emerge from the thorax, each ending in a tiny claw used for gripping fabric and mattress seams. Two antennae, each bearing several sensory receptors, extend from the head.
Key anatomical features include:
- Pronotum: a shield‑like plate covering the front of the thorax, rounded at the edges.
- Hemelytra: reduced forewings that are hardened at the base and membranous at the tip, but non‑functional for flight.
- Mouthparts: a piercing‑sucking rostrum capable of penetrating human skin to extract blood.
- Eyes: small, simple ocelli positioned on the sides of the head, providing limited vision.
Life stages differ in appearance. Nymphs progress through five instars, each slightly larger and darker than the previous. First‑instar nymphs are about 1.5 mm long, translucent, and become progressively more reddish after blood meals. Adults develop a fully sclerotized exoskeleton and the characteristic reddish hue.
When disturbed, the insect can emit a faint, sweet odor detectable by trained professionals. This scent results from defensive secretions released from abdominal glands.
Overall, the insect’s compact, flattened body, reddish‑brown coloration after feeding, segmented abdomen with fine setae, and specialized mouthparts define its recognizable morphology.