Yellowjacket is the common name for a particular group of wasps in the genus Vespula that can be recognized by their black and yellow striped markings. There are about 19 different kinds or species of yellowjackets living in North America. A closely related species which is black and white, and larger in size, is the bald faced hornet (Dolichovespula maculata).
Interesting Yellowjacket Facts
- Yellowjackets do not have barbs on the end of their stinger. This means they can repeatedly sting a single individual. And when they do sting, they release a chemical odor that infuriates and alarms other yellowjackets in the immediate area to attack and sting as well.
- Yellowjackets start a new nest each spring from a single queen that mated the prior fall. Only queens that mate can make it through the winter.
- Yellowjacket nests located behind walls often break through to the inside of the building as the nest expands in size during the summer. This type of nest should be removed or else the dead wasps will provide a food source for carpet beetles and other insect pests.
There are two species of yellowjackets in New England. The native eastern yellowjacket (Vespula maculifrons) builds its paper nest underground, usually in abandoned rodent burrows. Their large underground nests may contain up to a few thousand individuals. The second yellowjacket species in New England is the German yellowjacket, Vespula germanica which builds its nests behind walls, in attics and in closed spaces. This introduced species has large nests of up to a few thousand individuals. Yellowjackets are frequent scavengers and they are often encountered during cookouts, around dumpsters and in trash receptacles. Many people are stung as they cut tall grass and otherwise end up standing directly over a ground nest. Other people are aware of a wasp nest for the first time when an expanding nest in a wall void breaks through to the interior of a home or office. When this happens, large numbers of wasps are trapped indoors and they usually aggregate around windows as they try to find their way back outdoors.
All yellowjacket wasps are social insects and they aggressively protect their nest by powerful stings. Nests are created new each spring by overwintering mated queens. The workers expand the nest during the spring and summer. In the fall, after the males and females mate, the males rapidly die and the females overwinter and begin a new nest the following spring. Yellowjackets capture large quantities of flies; they feed largely on protein during the first part of the summer and then switch to fruits and sugars by the end of summer. When yellowjackets start their new nests in the spring, they are most vulnerable before they produce workers that can protect the nest. These nests are difficult to locate due to their small size. Once the nest is larger and workers are foraging, you can follow workers as they return to the nest. It is always a good idea to find the yellowjacket nest before these wasps find you.
Preventing Yellowjacket Stings
Yellowjackets can sting many times, and unlike bees that have a barbed sting, yellowjackets usually do not die after stinging. Once stung, the victim is marked by an alarm odor that excites nearby wasps to repeatedly sting the hapless victim. It has been estimated that about 40 people die annually from stings, and many others are hospitalized. People who have a history of allergies, heart problems, or known sensitivity to stings should be very careful and seek medical advice when stung. Most people only suffer temporary pain when stung. This pain can be reduced by cooling the affected area with cold water or ice. If possible, capture the wasp for identification. The venom of wasps can be used to desensitize people who have severe sting allergies. When stung out of doors, immediately vacate the area to distance yourself from a possible wasp nest. The best policy is to prevent wasp stings. When encountering a wasp, remain calm, especially if you are driving down the highway at high speeds. Pull over, stop and open all car windows to let the wasp escape before continuing. Look carefully for nests before doing yard or outdoor work. Wear foot protection out of doors. Do not eat tuna, chicken or other smelly foods outdoors when and where wasps are actively hunting for food. Wasps may enter soft drink containers before you lift them to your mouth since wasps are attracted to strong food odors. Wash hands and mouths of children before sending them out to play.
Wasps from several nests may be active in the same vicinity. When a single wasp finds food, it must return to the nest, share its food with the colony and then return to the food alone. Other wasps in the area may observe feeding by this individual and are then attracted to the immediate area by what scientists call social facilitation. When there are several wasps feeding, then even more wasps are attracted to the food. There are yellowjacket traps available that use food bait and an attractant inside of a clear container. Wasps are unable to exit the inverted cone trap as long as the container is kept upright and in the light. Effective lures for these traps are Grenadine syrup, tuna or coke. It is a good idea to place these traps along the perimeter of a picnic area before food is brought out to eat. Bring the food out just before you are ready to eat, eat quickly and clean up right away to avoid encountering numbers of these wasps. There are many stories of individuals who tried to use chemicals to control wasps and they ended up with multiple stings. Leave such heroics to professional pest control operators who should wear personal protective equipment. It is possible to observe wasps returning from their food source to their nest. By setting out small chunks of tuna, you can watch struggling wasps slowly fly at a fast walking pace back to their nest. This technique, called making a bee line, is made even more effective if you are patient enough to keep placing the food closer and closer to the nest until it is found. It is better to find and have nests eliminated in the early summer rather than wait until their numbers are built up to maximum at the end of the season.
Remember, wasps are an important part of nature and your best defense is to learn as much as you can about their biology and behavior. Here are some references to help you understand yellowjacket biology.
Copyright 2013-15 www.pestipm.org. All rights reserved.