Yellow Jackets

Several species of social wasps know commonly as yellow jackets are the smallest of the common vespids at about ½ inch long. Most species typically build their nests underground, so workers will come and go via an earthen tunnel that ends in a hole at the surface. Underground nests are often started in an abandoned mammal burrow or a similar underground cavity. The nest is expanded initially to fill the cavity, and the cavity is enlarged as the colony develops. Particles of earth and small stones may be piled up around the opening of the burrow that houses a large colony of the underground species. Yellow jackets will often use available openings at or near ground level. Yellow jackets for instance, have built extensive nests within voids of concrete block foundations or below railroad ties used in landscaping around patios. Whether in the ground or within a wall void yellow jacket nests are made of paperlike material and resemble the bald-faced hornets nests described earlier. As many as several thousand workers may be produced in a colony in one season. Colonies in certain areas of California and southern Florida will persist for more than a year, so are called perennial. These colonies develop more workers than typical colonies.
Some species of Vespula forage nearly exclusively on live prey, such as flies, caterpillars, and other insects, while other species forage strongly for meat from carcasses, garbage, and picnic tables to feed developing larvae. Yellow jackets also forage on sources of sugar or other carbohydrates, such as beer, fruit, and sweet beverages at picnic sites. Workers may also obtain sugars from the honeydew of aphids or scale insects. As new queens are produced in the colony in late summer, they demand sugars from the workers, which then forage aggressively for the honeydew and other sources of sugar. The tendency to scavenge at human food sources puts the yellow jacket in frequent conflict with people in picnic areas, parks, backyard patios and so forth. This conflict becomes particularly acute in the late summer when the number of workers foraging is at its peak, and some of their other sources of meat, prey and sugars are declining.
Yellow jacket workers tend to be somewhat unpredictable in their response to humans who approach the nest. Often a person approaching the nest is completely ignored, but sometimes a person simply walking by will be stung. Most serious stinging incidents occur when a nest is accidentally disturbed. Humans are usually ignored by yellow jacket workers away from the nest, so stinging incidents under such circumstances are caused by accidental tapping of the worker against some part of the body, between folds of clothing, under the arm or leg, or in the mouth when swallowing a beverage from a container that contains a foraging yellow jacket.
Many experts consider yellow jackets to be the most dangerous of the Hymenoptera in the United States, because of the insects nesting habits and foraging behavior and the potential for its venom to induce severe, life threatening allergic reactions in certain sting victims.
Danger: One can receive multiple stings from Yellow Jackets due to their emitting a chemical message to attract others to join in and assist with the attack.
Warning: Homeowners should never spay into a hole where Yellow Jackets are nesting in a wall void or the like. It could flush (drive) many into the interior of the home. Call the professional first!

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