How do bedbugs look? - briefly
Bedbugs are tiny, oval, wingless insects about 4–5 mm long, with a flat, reddish‑brown body that becomes swelled and darker after feeding.
How do bedbugs look? - in detail
Bedbugs are small, oval‑shaped insects measuring approximately 4–5 mm in length when unfed and up to 7 mm after a blood meal. Their bodies are flat and dorsoventrally compressed, allowing them to hide in narrow crevices. The exoskeleton is a matte, reddish‑brown color that darkens to a deeper rust hue when engorged.
The head is concealed beneath the pronotum, a shield‑like plate covering the thorax. Six legs extend from the thoracic segments, each ending in a claw for gripping fabric and wood. Antennae are short, segmented into five parts, and positioned near the mouthparts. The mouthparts form a pierce‑and‑suck apparatus, consisting of a elongated proboscis capable of penetrating human skin.
Key visual characteristics:
- Size: 4–5 mm (unfed), 6–7 mm (fed)
- Shape: Oval, flattened, resembling a tiny apple seed
- Color: Reddish‑brown; deepens to rusty red after feeding
- Exoskeleton: Hard, matte, non‑shiny
- Legs: Six, each with a tiny claw
- Antennae: Five‑segmented, short
- Wings: Absent; flightless
Life‑stage differences are noticeable. Nymphs resemble adults but are lighter in color, ranging from translucent to pale brown, and increase in size with each molt (five instars total). Adult females are slightly larger and more robust than males, though sexual dimorphism is minimal and not easily discerned without magnification.
When a bedbug has recently fed, its abdomen expands dramatically, creating a visible bulge and a glossy, blood‑stained appearance. After digestion, the abdomen contracts, and the insect returns to its flatter, matte form. These visual cues aid in identification during inspections.