What do blood‑drinking bedbugs look like?

What do blood‑drinking bedbugs look like? - briefly

Blood‑feeding bedbugs are 4–5 mm long, flat, oval insects with a reddish‑brown exoskeleton that swells and darkens after a meal. They possess short antennae and six legs ending in tiny claws.

What do blood‑drinking bedbugs look like? - in detail

Blood‑feeding bedbugs are small, dorsoventrally flattened insects measuring 4–5 mm in length as adults. Their bodies are oval and lack wings, giving a smooth, cigar‑shaped silhouette. The exoskeleton is a matte, reddish‑brown hue when unfed; after a blood meal, the abdomen expands and turns a deep crimson, sometimes appearing swollen and glossy.

Key morphological traits include:

  • Head: Short, concealed beneath the thorax, equipped with a slender, needle‑like proboscis that folds into a sheath when not in use.
  • Antennae: Four segmented, fine, sensory structures positioned near the eyes.
  • Eyes: Simple, lateral compound eyes providing limited vision, primarily for detecting light.
  • Thorax: Broad, bearing three pairs of short, robust legs adapted for crawling on fabric and mattress seams.
  • Abdomen: Segmented, capable of dramatic inflation after feeding; each segment bears tiny bristles (setae) that give a slightly fuzzy texture.
  • Color variation: Nymphs progress through five instars, each slightly smaller and lighter than the adult, with the same color shift after feeding.

Sexual dimorphism is minimal; males and females appear alike except for the female’s larger abdomen when gravid, which may appear slightly more rounded. Eggs are tiny, off‑white, and deposited in concealed cracks; they lack coloration and are invisible without magnification.

When observed under magnification, the mouthparts reveal a elongated labium housing the stylet bundle, a diagnostic feature differentiating bedbugs from other hematophagous arthropods such as ticks (which possess a scutum) or fleas (which have laterally compressed bodies). The combination of size, flattened oval shape, reddish‑brown coloration, and the characteristic swollen abdomen after a blood meal uniquely identifies these insects.