Bed Bug Color by Stage: Eggs → Nymphs → Adults (Exact Sizes + Colors)

Bed bugs don’t have one color—they change color as they grow. From pearly white eggs through five increasingly darker nymph stages to the iconic reddish-brown adult, bed bug color tracks almost perfectly with age. This stage-by-stage color progression is one of the most useful tools for identifying both the presence of bed bugs and how mature the infestation has become.

Stage-by-Stage Bed Bug Color Guide

Stage 1: Eggs — Pearly White

Color: Pearly white to off-white
Size: 1mm (pinhead sized)
Appearance: Barrel-shaped, slightly shiny, sticky surface
Where found: In clusters glued to mattress seams, furniture joints, baseboard cracks

Eggs do not change color after feeding—they remain white until they hatch (6–10 days at room temperature).

Stage 2: 1st Instar Nymph — Translucent / Bright Red (Fed)

Color (unfed): Nearly transparent, pale straw
Color (fed): Vivid bright red—blood visible through exoskeleton
Size: 1.5mm
Key visual: The most dramatic color change of any stage. Before feeding, nearly invisible. After feeding, an unmistakable red dot.

Stage 3: 2nd Instar Nymph — Straw to Light Tan

Color (unfed): Straw yellow to pale tan
Color (fed): Orange-red, abdomen clearly distended
Size: 2mm
Key visual: Starting to resemble small versions of adults, but still very pale

Stage 4: 3rd Instar Nymph — Medium Tan

Color (unfed): Light to medium tan, slightly brown
Color (fed): Orange-brown
Size: 2.5mm

Stage 5: 4th Instar Nymph — Light Brown

Color (unfed): Light brown
Color (fed): Reddish-brown, similar to small adults
Size: 3mm

Stage 6: 5th Instar Nymph — Medium Brown

Color (unfed): Medium brown, approaching adult coloration
Color (fed): Deep reddish-brown
Size: 4.5mm — nearly adult-sized

Stage 7: Adult — Reddish-Brown / Mahogany

Color (unfed): Reddish-brown to mahogany (apple seed color)
Color (fed): Deep crimson-rust, fully engorged appearance
Size: 5–7mm
Key visual: Flat, oval, six legs clearly visible, wing pads present but non-functional

Have Evidence Photos?

Found a bug but can't tell which stage it is? The color stage progression you just learned is exactly what our AI applies to your photo. Upload a clear image and our system will identify the life stage based on color intensity, body proportions, and size—giving you a precise developmental assessment.

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What Multiple Color Stages Tell You About Your Infestation

The mix of colors you find communicates directly how established the infestation is:

• Only white (eggs) or translucent specks: Very early catch—colony is just beginning. Easiest time to treat.
• Mix of pale and medium-brown nymphs with no adults: First generation has hatched but not yet matured. Still relatively early.
• Adults + nymphs in multiple shades + eggs present: Self-sustaining, multi-generational colony—requires comprehensive treatment immediately.
• Only adults, no eggs or nymphs: Recent introduction—likely a single mated female arrived recently.

For the full color breakdown including feeding transformation at each stage, visit the hub: what color are bed bugs.

Related Color Guides

• Are Bed Bugs White in Color? — Early-stage eggs and nymph identification
• Are Bed Bugs Red in Color? — When and why bed bugs turn red
• Bed Bug Color Before and After Feeding — The transformation at every stage

Have Evidence Photos?

Now you can read the color stage like a map of your infestation's age. Find out exactly what stage you're dealing with—upload your photos and our AI will not only identify the species but tell you which developmental stage and how to interpret the severity based on what's present.

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