PAPER WASPS INFORMATION & FACTS

(Polistes spp. and Mischocyttarus flavitarsis)

‘Umbrella wasp’, is a common term used to refer to ‘paper wasp’, because their nests resemble the shape of an inverted umbrella. Paper wasps earned their true name from the paper-like material they make from wood fiber and their saliva, which they use to build their nests out of.

Paper wasps are semi-social and live in small colonies, with a cast system. They eat nectar, as well as other insects, like flies and caterpillars. Unlike other species of wasps and hornets, paper wasps may re-use an old nest. Paper wasps are medium to large in size (16k-20 mm), have 6 legs, and are brown in colour, with yellow markings. There are some species with red markings. They are not aggressive, however if provoked or disturbed, or if they feel their nest is being threatened, they will give a painful sting.

Umbrella wasp nests are comprised of only a single comb with brood cells (individual compartments for their young). There is no paper covering around them. Nests are often built in residential yards, found hanging from branches of trees and shrubs, fences, porch ceilings, window frames, door frames, soffits, eaves, chimneys, vents and decks (railings and board joists). Indoors, nests are commonly hung from attic rafters and cathedral-style ceilings.

A paper wasp colony begins in the spring, when a fertilized female emerges from overwintering, to initiate the next generation of wasps, and rule as queen. As she builds the new nest, she lays a single egg inside each cell. Once her larvae hatch, she will care for them until they mature into infertile female workers, who will fulfill the worker role to expand the nest, forage for food, care for the queen (who continues to lay eggs to build the population), and the young.

In late summer, males and fertile females are hatched, and will mate so that the next generation of paper wasps can live on. All paper wasps die in the winter, except for the fertilized females who overwinter.

Interestingly, in a paper wasp colony, if the queen dies, the next most aggressive female worker wasp will take over as queen. While she has not been fertilized, she will lay unfertilized eggs, which will hatch as male paper wasps. As well, queens that are unsuccessful in starting their own new colony, will ‘join’ another. As a joiner, she will submit to the founding queen and fulfill the duties of a worker. If something were to happen to the founding queen, the joiner could rein as new queen since she is fertilized. There have been rare cases when the joiner has dominated the founding queen and taken over the colony. In these cases, the founding queen becomes a worker to the new queen.

If you come across a paper wasp nest, do not attempt to knock it down. In addition to the increased chances of being stung, paper wasps will re-build it. Pest Control for these wasps is to eliminate the wasps themselves.