The common yellowjacket species look similar – yellow or white abdominal patterns, abdomen narrow and attached to the thorax by a pedicel (“waist”) and smoky wings. I recently photographed yellowjackets at their underground nest in one of our pastures (Modoc County CA). These yellowjackets looked similar to the common aerial yellowjackets I previously photographed along the Truckee River in Nevada (“Common Aerial Yellowjacket” 09-16-12). However, the common aerial yellowjacket builds its nest above ground, and these yellowjackets had an underground nest.
Identified by the continuous yellow ring around each eye, this is the western yellowjacket (Vespula pensylvanica). The western yellowjacket generally builds its “paper” (masticated vegetable fiber) nest about 10cm to 15 cm under the surface of the ground, although occasionally it will build a nest in a dark above ground cavity. The nest consists of rounded combs attached to one another and surrounded by a many-layered envelope. Newly produced yellowjacket queens are the only members of the colony to survive the winter, overwintering in sheltered locations such as decaying stumps or under tree bark. These yellowjacket queens emerge from hibernation during the first warm spell of the spring and begin to establish new colonies.
Western yellowjackets do not store honey. They eat insects, dead animals and plant nectar, preferring high protein foods. Unlike bees, yellowjackets cannot communicate the location of food to other members in the colony. Western yellowjackets are common invaders at picnics or wherever food is served outdoors, as well as at garbage depositories.
Western yellowjackets do not have barbed stingers so do not leave a barb in the skin. They can sting repeatedly though. The western yellowjacket sting is used primarily for defense and usually causes intense yet temporary pain to humans. Because there is great variability among individuals in their reaction to stings, severe localized or generalized systemic reactions may occur, including anaphalaxis.
Native to the western half of North America, the western yellowjacket is found in all states west of the Rockies. Numbers fluctuate depending on the severity of spring weather.
I decided to use discretion and did not attempt to excavate this western yellowjacket nest.