Bed Bug Biology and Behavior

MEET THE BED BUG

Small, flat and easy to miss.

Adult bed bugs are reddish-brown, flat and oval, about the size and shape of an apple seed (roughly 5–7 mm, or ¼ inch). After a meal they swell and turn a deeper red.

Newly hatched nymphs are about the size of a poppy seed and almost see-through until they feed. Eggs are pearly white, about 1 mm long, and glued into cracks and seams, so they’re very hard to spot.

Why it matters for your heat treatment: their flat bodies let them squeeze into seams, cracks and wall voids that sprays and vacuums can’t reach. Heat gets in everywhere, as long as air can move around the furniture. See how to prepare

Bed bugs at every life stage lined up on a person’s fingers, from tiny newly hatched nymphs on the left to full-grown adults on the right — Every life stage on a fingertip, from newly hatched nymphs (left) to adults (right). Fresh blood meals turn them red; unfed bugs look pale and see-through.

LIFE CYCLE

From egg to adult in about five weeks.

Five nymph stages. A young bed bug must take a blood meal before each moult to reach the next stage.
About 5 weeks, egg to adult, in a warm home (about 37 days in ideal conditions).
Eggs hatch in 6–10 days. A female lays 1–3 eggs a day and 200–500 in her lifetime.
One pregnant female is enough to start an infestation. A lone male or a young nymph can’t.

Why it matters for your heat treatment: eggs are the hardest stage to kill. They survive 7 hours at 45 °C, so we hold every surface above 50 °C (122 °F) for at least 3 hours. See the research

BY THE NUMBERS

Bed bug facts that shape the treatment.

3–7 daysbetween blood meals

3–10 minto feed, and the bite is painless

6–10 daysfor an egg to hatch

200–500eggs in a female’s lifetime

~5 monthsadults can survive without food

5–20 fttravelled from a hiding spot to feed

Survival without food: average for adults in a Virginia Tech study (2011); cooler rooms stretch this further. Travel distance: US Armed Forces Pest Management Board.

WHERE THEY HIDE

Most bed bugs live within a few metres of the bed.

They choose tight, dark spots close to where people sleep or sit for long periods. Look for the bugs themselves, their shed skins, tiny white eggs, and dark spots of dried droppings.

Illustrated bedroom with numbered pins on the eight most common bed bug hiding spots

1
Mattress and box springSeams, piping, tags and the fabric underneath. The most common spot of all.
2
HeadboardCracks, screw holes and the gap against the wall.
3
Bed frameJoints, corners, rails and slats.
4
NightstandDrawer joints, corners and the underside.
5
Dressers and chests of drawersInside the drawers, the frame joints and the back panel.
6
Baseboards and outletsThe gap where the wall meets the floor, and behind outlet and switch covers.
7
Picture frames, mirrors and wall hangingsBehind them and in the frame corners.
8
Rugs and carpet edgesUnder area rugs and along the carpet edge.

Why it matters for your heat treatment: every one of these spots has to reach 50 °C. Prop mattresses up on empty boxes to leave a gap for hot air, open drawers and closets, and pull furniture at least 6 inches from the walls so hot air can reach in. See the setup guide

HOW THEY BEHAVE

Why bed bugs are so hard to get rid of.

Night feeders

They hide by day and come out to feed while you sleep, usually at night. Hungry bed bugs will also feed in daylight.

Painless bites

A bite takes 3–10 minutes and you won’t feel it. Reactions vary widely: some people get itchy welts, others show no marks at all.

Hitchhikers

They travel in luggage, used furniture, clothing and moving boxes, and can be picked up on buses, in taxis and in theatres.

Hard to spray away

Many bed bugs are resistant to common pesticides, and sprays or foggers can scatter them into walls and neighbouring units.

Not known to spread disease

Health Canada notes bed bugs are not known to transmit disease. Scratching bites can still lead to skin infections.

Why it matters for your heat treatment: don’t use sprays, foggers or “bug bombs” before your treatment. They drive bed bugs deeper into walls and next door, where the heat has to work harder to reach them. Read the preparation checklist

WATCH

See bed bugs up close.

Start with our own short overview, also on our YouTube channel, then two short videos from trusted producers. Those play on YouTube in privacy-enhanced mode.