Adult bed bug anatomy
- Length: 5–7 mm — roughly apple-seed sized.
- Shape: oval, flattened side-to-side when unfed; rounded and elongated when engorged.
- Colour: reddish-brown unfed, deeper red-maroon immediately after feeding.
- No wings — bed bugs cannot fly or jump under any circumstances.
- 6 legs, prominent antennae, short wide pronotum (shield-like plate behind the head).
- The abdomen is segmented, accordion-like, visible when the bug has fed recently.
Nymphs: the harder-to-see life stage
Nymphs are juvenile bed bugs that pass through five instars (molts) before reaching adulthood. Each instar requires at least one blood meal to proceed to the next. First-instar nymphs are roughly 1.5 mm — nearly invisible without magnification and translucent enough that you can see the blood meal through the body wall. By the third instar they're about 3 mm and show the characteristic reddish-brown colouring of an adult, just smaller. The presence of nymphs in multiple size classes confirms an active, reproducing infestation rather than a single transported bug.
Eggs and shed casings
Eggs are 1 mm long, oval, pearlescent white, and laid in clusters of 5–15. Female bed bugs attach them with a sticky secretion — you can't simply knock them off a mattress seam with your fingernail. As the egg matures (6–10 days at room temperature) the developing nymph inside becomes faintly visible and the egg takes on a slight yellowish tinge. After hatching the empty shell (the 'egg case') persists in the harborage, providing a count of past reproductive activity. Shed casings from molts look like hollow, translucent, slightly curved versions of the bug at each life stage. Finding multiple empty casings confirms the infestation has been active for weeks, not days.
Signs you're more likely to see than the bugs themselves
- Dark or reddish-brown spots on mattress seams, sheets, and headboard joints — digested blood from previous feedings.
- Shed casings — translucent bug-shaped shells from each of the five molts. Found in mattress seams, headboard joints, bed-frame corners.
- Egg cases — tiny, flat, whitish shells 1 mm long, in clusters in crevices.
- A sweet, musty, slightly sickly odour in heavy infestations — described as overripe raspberries or coriander by different inspectors.
- Bites in lines or clusters on skin (typically discovered in the morning, on exposed sleep areas — arms, face, back).
- Live or dead bugs in seams — found during active inspection with flashlight, rarely visible in ambient light.
Bed bugs vs look-alikes common in BC homes
| Bug | Size | Shape | Key difference |
|---|---|---|---|
| Bed bug (adult) | 5–7 mm | Oval, flat | Reddish-brown, no wings, found near sleeping areas |
| Carpet beetle larva | 4–5 mm | Elongated, hairy | Covered in bristle-like hairs; feeds on fabric, not blood |
| Book louse (psocid) | 1–2 mm | Elongated | Pale grey, found near books/moist paper, not beds |
| Bat bug | 4–5 mm | Near-identical to bed bug | Longer hairs behind head; only if bats roosting in structure |
| Spider beetle | 2–4 mm | Round, shiny | Globular abdomen, longer legs; found in pantry/attic, not bed |
Where to look in a Metro Vancouver bedroom
Metro Vancouver bedrooms have specific structural features that create harborage: laminate headboards with hollow extrusions (common in Ikea-style frames throughout Richmond and Burnaby condos), platform beds with integrated storage compartments beneath the mattress, and older wood-frame bed structures with mortise joints and rough-sawn wood surfaces. In dense rental stock — think the pre-1980 wood-frame apartment blocks common in East Vancouver and New Westminster — bed bugs can also establish in wall cavities behind the headboard, in cracks along the baseboard behind the bed, and inside outlet plates on the wall adjacent to the sleep surface. Our technicians always inspect the full sleep perimeter: mattress, box spring, frame, headboard, nightstand, nearest wall outlet, and baseboard — not just the mattress seam.
When to call for an inspection vs DIY diagnosis
If you find dark spots and shed casings on a mattress seam, that's sufficient evidence to call for treatment — you don't need to find a live bug. The diagnostic threshold is: at least two types of evidence (spots + casings, or live bug + bites, or casings + bites) from the same location. A single bite is not enough to call it bed bugs — up to 30% of people have no visible reaction to bed bug bites, and many other insects bite nocturnally. See our [bite identification guide](/guide/bed-bug-bites-vs-other-bites) for the full differential. If you're in a Metro Vancouver rental and find evidence, photograph it immediately and send written notice to your landlord referencing [BC RTA Section 32](/guide/rtb-section-32-landlord-bed-bug-obligations).