Bed bug

How to recognise it

These are the features that identify a bed bug. Each one is described in words so the identification works without the diagram.

1. Adults are 4 to 5 mm, roughly the size and shape of an apple seed — flat and oval when unfed, swollen and elongated to nearly cylindrical after feeding.
2. Colour is mahogany to reddish-brown, becoming darker and redder after a blood meal.
3. The body is wingless with short, thick antennae and a distinctly flattened profile that lets it occupy very narrow seams.
4. The abdomen has visible horizontal ridges giving a segmented, banded appearance across the back.
5. Nymphs are smaller and translucent to pale yellow-white, becoming visible mainly after feeding when a red blood spot shows through.

What it leaves behind

• Dark, ink-like fecal spotting along mattress seams, in the box spring frame, along headboard joints, and behind loose wallpaper. The spots bleed slightly into fabric like a felt-tip pen mark, which distinguishes them from ordinary dirt.
• Shed skins — pale, empty, adult-shaped husks — accumulated in harbourage areas. These are often the easiest evidence to find.
• Eggs about 1 mm, pearly white, cemented into crevices in small groups.
• A sweet, musty odour in heavily infested rooms.

Why an infestation persists

Bed bugs feed on blood, usually at night, and spend the rest of the time hidden in tight seams and crevices close to where people sleep. This harbourage behaviour explains why a single surface spray application fails: the population is inside mattress seams, bed frame joints, and behind skirting, not on the open surfaces that get treated. They survive long periods without feeding, so leaving a room empty does not clear it. They are not associated with dirt or poor housekeeping — a clean home is as susceptible as any other, and clutter matters only because it creates more places to hide. They are not known to transmit disease to people, which is a genuinely important thing to know for anyone frightened by an infestation.

Where it occurs

Throughout the United States in every kind of housing and lodging, with the greatest burden falling on multi-unit rental housing.

Where to look for it

• The mattress seam, piping, and tag, working slowly with a torch held at a low angle so the seam casts a shadow.
• The box spring, especially the underside where the dust cover meets the frame — often the heaviest concentration in the room.
• Every joint of the bed frame, and the screw holes and dowel holes in a wooden frame.
• The headboard, including its back face and any gap where it meets the wall.
• Seams and folds of upholstered furniture within about two metres of where someone sleeps, including a chair someone naps in.
• Behind loose wallpaper, under the edge of carpet, and inside the plastic housing of a bedside socket or switch.

When you see it, and why

Bed bugs have no meaningful season indoors, but reports rise with travel, so summer and the winter holidays produce noticeable peaks in new introductions rather than in existing populations. This matters for one practical reason: an infestation that appears shortly after a trip is usually a recent introduction and is often still confined to one room, which is the easiest stage at which to resolve it. An infestation discovered with no travel history is more likely to have been building quietly, or to have arrived from an adjoining unit, and should be inspected more widely from the start.

What getting the identification wrong costs you

The most common error is the reverse of the one people fear: carpet beetle larvae are the same length and are routinely mistaken for bed bugs, and the difference is a fortnight of unnecessary distress and sometimes a treatment nobody needed. Bristly and carrot-shaped is a carpet beetle; flat, oval, and hairless is a bed bug. The costly error in the other direction is treating marks on skin as proof: bites are not reliably identifiable, and a whole-home treatment bought on the strength of a rash, with no physical evidence found, is money spent on a guess.

What a professional actually does

A proper visit begins with an inspection that finds and documents physical evidence — live insects, shed skins, or fecal spotting — before anything is quoted, and extends to adjoining rooms and, in a multi-unit building, to neighbouring units. Interceptors under the bed legs are placed to measure whether the work is succeeding rather than to rely on whether anyone is still being bitten. Expect at least one follow-up and a clear statement of what preparation is required of you, since inadequate preparation is the most common reason a competent treatment fails.

What it costs

Bed bug work is priced per room rather than per property, so the figure moves with how far the population has spread — which makes early inspection the single largest cost lever available to you. Whole-property approaches cost considerably more than a single-room treatment caught early. If you rent, do not pay before establishing responsibility: in most states an established infestation is a habitability matter, and in a multi-unit building a single-unit treatment you funded yourself will very likely fail anyway.