Social, Well-armed, Predatory Insects… Paper Wasps

By Keith Hutton on April 19, 2016 in Other

Paper wasps have built a nest under eaves at the back of my house and I’ve been watching it increase in size over the last five months of spring and summer. During the day about 25 wasps, 10-15mm in length, attend the nest, and throughout the day there are always two or three zooming in and out, with characteristically long legs dangling down. These social insects have long thin wings and a slender body with a very narrow waist; they appear dark brown in colour with rufous-orange body stripes and rear end; angled antennae are bright orange.

After sunset the nest is covered with roosting wasps and the activity appears to stop for the night. I’m pretty sure they are Common Paper Wasps, but there are many similar species in Australia so identification is difficult. These belong to a group of around 300 species known as Polistes wasps, which are represented throughout the world in all but the coldest regions.

There are three ways to start the colony cycle in spring. In the first way, several queens start by building a single hexagonal cell attached to the nest site. More cells are then added to form a small upside down wine glass shape, and then built up into a big thick crumpet, utilising new generations of workers as they emerge. Larvae develop in individual cells from single eggs deposited by a queen. When grubs are mature, the cells are sealed by the workers then the larvae pupate and later emerge as adults. Alternatively, nests several years old may be re-used, or old nests may be occupied all year.

Paper wasps make their nests from a mixture of chewed wood fibre and saliva that sets like grey paper. Adult females that hibernated over winter, and were inseminated the previous autumn, create breeding colonies in spring. There are no males at this time as they never survive the winter. Only females are produced in the new colony at first, and these virgin females become workers and continue to build the new colony. In late summer and early autumn males and potential queen females are produced. These disperse and mix randomly with those from other colonies and mate, and the cycle continues.

Paper wasps are found throughout Australia and New Zealand. They are common around the outside of homes and in suburban areas, woodlands, forests and heaths, where they build nests on walls, doorframes, around windows, under eaves, and on fences, as well as on vegetation in gardens and traditional natural sites.

Food caught by workers is mainly caterpillars and small spiders that are immobilised with a sting, then dismembered and delivered to the colony in small portions. Adults also visit flowers and consume nectar and pollen.

Paper wasps are successful and usually not aggressive; they normally use their stings for self-defence and immobilising prey. However, they will defend their nests and sting interlopers repeatedly when a nest is disturbed. They play important roles in pest control, pollination and plant protection in natural, agricultural and horticultural systems. Consequently they are generally recognised as beneficial insects that are of least conservation concern.