However, the workers are vegetarians and need sugary food. For most of the summer, they get some of their food from nectar, but the bulk is obtained from the grubs. When workers return with insect prey, the grubs raise their heads to be fed and saliva flows from their mouths. This is sugary and is eagerly sipped by the workers.

In late summer, the queens stop laying eggs and, as a result, there are fewer grubs to be fed. The many workers are then forced to go out and forage to feed themselves. They feed on honeydew, sap and other plant exudates. Fruit is attractive when it is over-ripe.

Life-cycle of Wasps

The young queens emerge from the nest in the autumn and, after mating, select hibernation sites in protected situations, such as garden sheds and under bark. They normally cling with their jaws to material such as sacking or curtains. It is not until the following spring that hibernation comes to an end and the surviving queens select nest sites. The two common species nest in the ground in banks, or often amongst roof rafters or in sheds. The queen builds her nest of wood which she has scraped from dead wood, fencing, garden sheds etc., and after it has been mixed with saliva she spreads it out with her jaws and tongue to make a slightly undulating fragile wafer-like paper.

The nest consists of an outer covering of several layers of paper, and a number of combs each consisting of many six-sided cells. A single egg is laid in each cell by the queen. 7 to 10 days later, the larvae hatch and are fed on dead insects by the queen. When fully fed, the larva seals its cell with a silk-like membrane and then pupates. When the final transformation takes place the wasp, a sterile worker, bites its way out of the cell and helps in all activities of the colony except egg-laying, which only the queen is capable of carrying out. From laying the egg to nest emergence of the adult takes from 3 to 6 weeks. The workers excavate the nest cavity, build more combs, feed the larvae with insects and later in the year construct the large cells for queen-rearing.

On average each cell in the comb is used twice and in a nest of 7 combs it is estimated that between 25,000 and 30,000 wasps may be reared during the season in a large nest.

Towards the end of the summer the original queen lays a number of eggs which produce male wasps only and these mate with the new queens. At the onset of the cold weather during the autumn all the wasps die, with the exception of the new queens which fly away seeking hibernating sites.

Photo below shows new queens hibernating in a drawer.