-Paper Wasps: Contrary to popular belief this is not the image of the remains of an alien spaceship. It is the architecturally designed nest of a paper wasp colony. Polistes variabilis is probably the species responsible for building and maintaining this nest. The nest is mushroom-shaped and suspended by a slender stalk. The cells, as illustrated, are arranged in regular order similar to a honeycomb. Only solitary, fertile females are supposed to survive over winter. This is probably incorrect as last winter we found about 20 paper wasps huddled together in a cardboard box in our shed. They departed as soon as the day length increased and the weather became warmer. Paper wasps are brown in colour and are about three centimetres long.
They set to work in spring to construct their nest. Wood fibres are scraped off tree trunks or fence posts, mixed with saliva and formed into a coarse paper-like material. The wasp was the world’s first paper maker. An egg is deposited in each cell and after hatching is fed chewed up caterpillars by the adults. The adults are very conscientious in feeding the larvae because the immature wasps secrete a fluid from their mouths, which is relished by the adults. As the colony grows it increases in size by the addition of more cells to the circumference. When the larvae pupate they spin a silken screen across the mouth of the cell. Some screened cells may be seen in the centre of the image. As winter approaches activity decreases, the nest is abandoned and some wasps hibernate in suitable places such as cardboard boxes strategically placed in sheds.
The paper wasps, at Yallaroo, construct their nests under the eaves, above the roller doors in our shed and often in shrubs. They will attack when disturbed and have a painful sting. We have been stung a few times when we have accidentally disturbed a nest. We tolerate the occasional attack because paper wasps are part of the bio-diversity of Yallaroo and because they exert biological control over insect pests.