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 YELLOW JACKETS
Common Name: Yellowjackets
Scientific Name: Vespula species and Dolichovespula species.
Introduction. Yellowjackets receive their common name from their typical black and yellow color pattern. They are worldwide in distribution with about 16 species occurring in the United States.
 Recognition.
Adult workers measure
3/8 to 3/4 inch long,
depending on the
species, with their
respective queens about
25% longer. The abdomens
are usually banded with
yellow and black and
some species with white
and black. The worker
abdominal color pattern
is usually distinctive
for each species.
Similar Insects.
(1) Baldfaced hornets, (Dolichovespula
maculata) are mostly
black with ivory-white
markings. (2) European
hornets, (Vespa Crabro)
are very large (up to 1
3/8“ long), and are
brown, yellow and
rust-colored. (3) Honey
bees (Apis mellifera)
are more hairy and the
abdomen is brown and
orange, not banded with
yellow and black; (4)
Drone flies and flower
flies (Diptera:
Syrphidae) may resemble
yellowjackets and bees
but have only one pair
of wings.
Representative Species.
1. The German
yellowjacket, Vespula
germanica, occurs
throughout most of the
United States except in
the far south. The nests
are constructed in
attics, above eaves, in
soffits, false ceilings,
and in deep boxsills of
bay windows and
cantilever construction.
2. The eastern
yellowjacket, Vespula
maculifrons, is common
east of the Great
Plains. The soccer
ball-size nests are
constructed in the
ground and wall voids of
buildings.
3. The common
yellowjacket, Vespula
vulgaris, is found
throughout most of the
United States.
4. The aerial-nesting
yellowjacket,
Dolichovespula arenaria
builds an exposed paper
nest (similar to that of
the baldfaced hornet) in
shrubs, trees and on
sheltered structural
surfaces.
Biology.
Yellowjackets are social
insects and live in
colonies. The adults are
represented by workers
which are sterile
females, queens (fertile
females), and males
which come from
unfertilized eggs and
usually appear in late summer.
Typically, only inseminated queens overwinter and do so in sheltered places. In the spring, they use chewed-up cellulose material to build up a paper carton nest of a few cells which will eventually consist of 30 to 55 cells covered by a paper envelope.
One egg is laid in each cell and the queen feeds the developing larvae chewed up insects, spiders, and nectar. After about 30 days, the first 5 to 7 workers emerge and shortly thereafter take over all the work except for egg laying. The nest will eventually consist of a number of layered paper combs (attached one below another) and are usually covered with a multi-layered paper envelope. Nest size varies from 300 to 120,000 cells, averaging 2,000 to 6,000 cells, and usually contains 1,000 to 4,000 workers at its peak. Later in the season, larger reproductive cells are built in which queens will be reared; males are usually reared in old worker cells. The colony is then entering the declining phase. The newly emerged queens and males leave the nest and mate. Only the inseminated queens hibernate and survive the winter. The founding queen, the workers, and the males all die.
Habits. Depending on the species, the overwintered queen will usually select either a subterranean or aerial nesting site. Most of the pest species are ground nesting. However, the German yellowjacket usually nests in buildings while the eastern and common yellowjackets occasionally nest in buildings.
Those nesting in the ground typically select areas bare of vegetation or else clear an area around the entrance. There are nest entrance guards to protect the colony. Yellowjackets are very slow to sting unless the nest entrance is approached and then they are quite aggressive. Each can sting a number of times, inflicting much pain. Some people become hypersensitive to their stings and future stings can become life-threatening. Those nesting in or on buildings are only a problem when the nest or nest entrance is located near human activity. Overwintering queens may enter the living space during the winter seeking warmth, or in the spring when they are looking for a nest site or just trying to get back outside.
Control. Yellowjackets are considered beneficial insects because their food consists mostly of pest insects and spiders. However, if their nest is located close to occupied buildings, recreational areas, or within structures, then control is warranted. During the day, a careful inspection by a Rottler technician will reveal where the nest entrance is for each colony to be controlled. If it is a ground nest, then the entrance hole will be treated with an appropriately labeled pesticide dust. If the nest is located in a wall void, then the void will be treated via the entrance hole or a temporary injection port. Ideally the wall void nest area should be opened up and cleaned out to prevent future secondary pest problems and decay odor and stains.
Cultural Control & Precautionary Measures. People and pets should be kept away from yellowjacket nest entry points. Entry holes should not be closed off until the colony has been destroyed and no further activity is noticed. Only gaps through which yellowjackets gain entry to indoor living spaces should be sealed immediately, as they are discovered. If yellowjackets chew through a wall or ceiling from the nesting cavity and become a health threat to the occupants, that room or area of the residence should be evacuated and isolated pending the arrival of a Rottler technician, who will remedy the situation.
Locations
Serving the St. Louis Metropolitan area since 1956, including
Arnold, Ballwin, Chesterfield, Crestwood, Creve Coeur, Des Peres,
Fenton, Florissant, Kirkwood, Maryland Heights, Overland, St.
Charles, Webster Groves, Wentzville and surrounding areas.
In Illinois: Belleville, Collinsville, Edwardsville, Columbia,
Madison, Waterloo, O’Fallon, Granite City, Alton, St. Clair, Monroe
and surrounding areas.
Columbia & Jefferson City, MO and surrounding areas. |
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