One reason bed bugs spread so successfully is because the youngest ones are incredibly small.
They’re easy to overlook unless you know exactly what you’re looking for.
Eggs
Around one millimetre long.
Tiny, white and often hidden in narrow cracks.
Newly hatched nymphs
Around 1.5 millimetres.
Almost transparent before they’ve had their first blood meal.
Older nymphs
They gradually become darker and larger after each moult.
Each stage looks like a miniature version of the adult.
Adults
Usually between five and seven millimetres.
Large enough to see without any special equipment.
Something that surprises many people
People often imagine they’ll spot the insects first.
In reality, we frequently notice the droppings before we ever see a live bed bug.
That’s because the insects stay hidden while the evidence gradually builds up around them.
My advice
Don’t rely on size alone.
Always look at the whole picture—droppings, eggs, cast skins and hiding places together.