How do bedbugs look at all stages? - briefly
Eggs are tiny white ovals about 0.5 mm long, adhered to fabric or cracks; each of the six nymphal molts enlarges the insect, turning from translucent to reddish‑brown and acquiring the flat, oval adult form, which measures 4–5 mm, has a reddish‑brown body, visible non‑functional wings, and a pointed beak.
How do bedbugs look at all stages? - in detail
Bedbug development proceeds through a series of distinct morphological phases, each with characteristic size, coloration, and anatomical features.
The first stage is the egg. Eggs are tiny, about 0.5 mm in length, and appear as translucent, white ovals. They are laid in clusters and glued to surfaces such as fabric seams or wall cracks. The shell is smooth and lacks any visible segmentation.
Following hatching, the insect enters the nymphal period, which consists of five instars. Each instar resembles a miniature adult but differs in size and pigmentation.
- First instar: Approximately 1.2 mm long, pale ivory to light brown, lacking fully developed wing pads. Antennae are short, and the abdomen shows a single dark spot near the posterior edge.
- Second instar: Grows to about 1.6 mm, coloration deepens to a light brown. Two small dark spots appear on the dorsal abdomen, and the thorax becomes more robust.
- Third instar: Reaches 2.0 mm, exhibits a medium brown hue. Three distinct dark dorsal spots are visible, and the legs lengthen, improving mobility.
- Fourth instar: Measures roughly 2.5 mm, color darkens to a reddish‑brown. Four dorsal spots are evident, and wing pads become more pronounced, though still non‑functional.
- Fifth instar: Approaches adult size at 3.0 mm, displays a dark brown to reddish‑black coloration. Five dorsal spots are prominent, the abdomen expands, and the wing pads are fully formed but remain vestigial.
The final stage is the mature adult. Adults measure 4.5–5.5 mm in length, with a flat, oval body. The dorsal surface is uniformly reddish‑brown to mahogany, and the abdomen bears a single, well‑defined dark stripe that runs the length of the insect. Legs are long and slender, ending in small claws adapted for clinging to fabric. The head features a beak‑like proboscis used for blood feeding, and the antennae are segmented, providing sensory input.
Throughout the life cycle, the exoskeleton hardens after each molt, resulting in a progressively tougher and more pigmented exterior. Size increments and the emergence of dorsal markings are reliable indicators for distinguishing each developmental stage.