Western Pest Services - Pest Library

Pest Library

Yellowjacket
Vespula spp., Dolichovespula spp.

Class:

Insecta

Order:

Hymenoptera

Family:

Vespidae

Size & Characteristics:

Yellowjacket adult workers are 3/8-5/8 in (10-16 mm) long, depending on species; queens are 25% longer. Wings are folded lengthwise when the yellowjacket is at rest.

Color:

Abdomen usually has yellow and black bands, but some species are white and black, and two northern species have red markings.

Geographic Range:

All around the world; 16 species in the United States

Comparison with other species:

Baldfaced hornet is mostly black, with light markings mostly on face but also on thorax and end of abdomen. European hornets are large, to 1 3/8 in, and are brownish with orange bands. Honey bee has hairy eyes, and its abdomen is not banded with yellow and black. Some clear-wing moths look like yellowjackets, but have mouths that are siphons.

Habitat:

A paper-carton nest which eventually has 30-55 compartments surrounded by a paper "envelope". It is made of chewed cellulose by a queen who has overwintered and is ready to lay her eggs, one in each compartment. Eventually there will be a number of paper-like combs attached one below the other, and covered with many layers of "paper".

Food:

Insects and nectar.

Biology:

Yellowjackets are social insects that live in colonies. Each colony has a queen that lays the eggs, female workers that do not reproduce, and males that come forth in late summer, being reared in the same cells that were earlier used for the workers. Larger cells for rearing queens are built at the end of the season. Mating occurs in fall after newly emerged queens and males leave the nest. Only queens who have mated hibernate and live through the winter. The past season's queen who built the nest, as well as the workers and the males, all die.

Invasion:

Depending on the species, nests may be built on the ground, or in shrubs, trees, or buildings, such as houses, garages, and sheds.

Damage:

Yellowjackets are beneficial as they eat many pest species. They may sting when the nest entrance is approached, and can be aggressive, stinging several times.