Had a wasp nest removed from the shed — will the wasps that were out foraging just build another one in the same place?

The returning wasps have nowhere to go and no ability to start over, and that is why they thin out day by day exactly as you are seeing.

A wasp colony has one queen. Every wasp you see flying is a sterile female worker who cannot lay eggs, cannot found a nest, and has no function outside the colony. When the nest goes, the returning foragers have lost the thing that gave their behaviour a purpose. They mill around the site for a few days — this is the confusion you are watching — and then die off or drift away. It is usually over within a week.

So the answer to question 1 is: nothing, and they cannot regroup. There is no scenario where those dozen wasps rebuild.

For question 2, split it into this year and next year, because the answers are opposite.

This year: no. Nests are annual. A queen founds one in spring, it grows through summer, and the whole colony dies in autumn — every worker, and the old queen. Nobody overwinters in the nest and nobody reuses one. So nothing will move into that corner for the rest of this season.

Next year: quite possibly, and not by the same wasps. New queens produced at the end of summer mate, overwinter somewhere sheltered, and each founds a fresh nest in spring. They look for the same qualities your shed corner had: dry, sheltered, out of the wind, with a small entrance. Those qualities do not change over winter.

So you are not at risk of a repeat now, and you are at slightly elevated risk in April — not because of any scent trail, but because the location was genuinely good and will be judged good again.

The thing worth doing, and it is a spring job rather than a now job: close the gap.

Since the appeal is the cavity and its small entrance, removing it removes the site. Fine mesh over the gap, or filling it if it is not doing anything structural, is far more effective than any spray or deterrent. Do it in late winter before queens are scouting — March in most temperate places — because doing it now risks sealing something in and doing it in May risks sealing something in that you have not noticed.

Also worth removing the old nest material if it is still there once the activity stops. Not because it attracts wasps — it does not — but because it attracts beetles and moth larvae that feed on it, and those are a genuinely more annoying shed problem than the wasps were.

On doing nothing being fine: mostly yes, with one exception worth naming.

If the nest was large and in a roof void rather than open in a corner, the abandoned nest can hold a lot of dead brood, and in a warm space that can smell for a couple of weeks and attract flies. In an open shed corner with airflow this is a non-issue.

Also, for what it is worth, a wasp colony eats an enormous number of caterpillars and aphids over a summer. If a future nest is somewhere you do not walk past — high on a garage, in a hedge — leaving it there is a genuinely reasonable choice for a garden, and it dies on its own in October. The shed doorway was not that.