Wasps have stripped wood from the fence in the picnic area, leaving light-coloured lines on the weathered grey boards. All British social wasps make their nests out of paper and they make the paper out of wood fibres and saliva.
In the spring, a new queen wasp, already fertilised when she left her old nest last summer, found a new nest site, somewhere near the picnic area. She built between twenty and thirty cells out of paper made from the wood fibres she collected from the fence.
A queen wasp collects wood to begin constructing her nest
She laid an egg in each cell and tended them alone until they developed into sterile female worker wasps; she then handed over to the workers the task of collecting more wood pulp to build the growing nest while she concentrated on her real job: laying more eggs.
The workers collected wood fibre for as long as the nest was growing. By this time of year, the nest will have produced males and new fertile queens and the old queen will have stopped producing eggs; the nest no longer needs to grow and the workers have stopped stripping wood from the fence.
Wasps forage among the picnickers.
Wasp larvae produce a sugary honeydew that is a significant part of a worker wasp’s diet. As the number of larvae in the nest falls, the workers begin to starve. The old queen is dying and the social structure of the nest gives way as the relationships that have maintained it fail. The wasps resort to cannibalism and piracy and instead of collecting wood pulp from the picnic area fences, they steal sugar from picnickers and drown themselves in beer bottles.
The first frost will kill what remains of the old nest but the new queens will hibernate and next spring will be looking for a source of wood fibre to begin their new nest.