What Are the Best Physical Signs of an Infestation?

Ranked by How Much They Prove

1. A live insect, in a harbourage. Settles identification and location at once
2. Eggs cemented into a seam. Proves a breeding population and proves you have found the harbourage
3. Cast skins, several sizes. Proves feeding and development over weeks
4. Dark spotting clustered in a seam. The commonest and most useful, especially for judging how far it has gone
5. A live insect wandering on a floor. Could have arrived last night; needs context
6. Blood smears on bedding. Suggestive, not conclusive
7. Bites. A prompt to look, and nothing more

Anything in the top four is enough to act on. You do not need several of them and you do not need to keep looking once you have one.

Photographing It So Somebody Can Use It

Most photographs of bed bug evidence are unusable, for the same three reasons every time: too far away, too dark, and no sense of scale.

1. Take the wide shot first. The whole bed, or the whole item, so the location is obvious. Then move in
2. Then a medium shot showing which part of the item — the head end of the mattress, the third drawer, the corner of the base
3. Then the close-up. Tap to focus on the mark itself, not the background
4. Put something in the frame for scale — a fingertip, a coin, the edge of a ruler
5. Light it from the side, not from directly in front. A phone torch held by somebody else at a low angle beats the built-in flash every time
6. Do not use flash on a dark seam. It flattens the texture and washes out exactly the detail that identifies it

Capturing a Specimen

If you find a live one, it is worth keeping — it is the only evidence that rules out carpet beetle, fleas and spider beetles outright.

• Do not squash it. A flattened insect is much harder to identify
• A small clear sealed bag, a jar, or a piece of clear tape folded over with the insect inside
• Photograph it against something white, with something for scale
• Note where it was found — that is half of what it tells anybody

What To Write Down

1. The date you first noticed anything
2. The date you found the physical evidence
3. Which room, and exactly where on which item
4. What you found — spotting, skins, eggs, insect
5. How many rooms in the property have beds in them
6. Whether anybody has changed rooms recently
7. Anything you have already sprayed, moved, bagged or thrown out

Those seven answers are most of an inspection's briefing, and they take two minutes to write down.

Twyford: Why This Matters More Than It Sounds

A good photograph and a clear location do three things: they get identification settled before anybody travels, they let the scope be discussed properly on the phone, and — in a rented property — they are what a report to a landlord or an agent should rest on.

In a dispute months later, dated photographs of evidence in place are worth considerably more than anybody's recollection of what was said.