What do the chitinous skins of bedbugs look like? - briefly
The bedbug’s outer covering is a hardened, brown‑to‑reddish exoskeleton made of chitin, giving the insect a smooth, slightly glossy appearance. It is segmented, with a thin, translucent cuticle that reveals underlying organs and creates a flattened, oval body shape.
What do the chitinous skins of bedbugs look like? - in detail
The outer covering of bedbugs consists of a thin, semi‑transparent chitinous exoskeleton that appears pale‑yellow when the insect is unfed and darkens to a reddish‑brown after a blood meal. The cuticle is composed of several layers: an inner, flexible epicuticle; a middle, sclerotized exocuticle that provides rigidity; and an outer, waxy layer that reduces water loss.
Surface texture is generally smooth and slightly glossy, with microscopic ridges that run longitudinally along the dorsal plates. Minute setae are scattered across the pronotum and tergites, giving a faint, velvety feel under magnification. The exoskeleton is divided into distinct plates: a rounded pronotum covering the thorax, paired dorsal tergites on the abdomen, and a ventral sternum that protects the internal organs. Legs and antennae terminate in hardened cuticular segments, each bearing tiny sensory pits.
Key visual characteristics:
- Color transition: pale‑yellow → reddish‑brown after feeding.
- Transparency: allows internal organs to be partially visible in unfed individuals.
- Gloss: low‑sheen surface with fine longitudinal striations.
- Setal distribution: sparse, short hairs on dorsal plates; denser on leg joints.
- Microstructure: hexagonal nanopatterns on the exocuticle, visible under scanning electron microscopy.
When the insect expands after ingesting blood, the cuticle stretches, causing the dorsal plates to bulge outward and the overall silhouette to become more rounded. This expansion does not alter the fundamental texture but can temporarily increase the opacity of the exoskeleton.