Yellowjackets (Vespula spp. and Dolichovespula spp.) are beneficial insects. Just keep repeating that to yourself when you're chased or stung by these yellow and black marauders! Yellowjackets have actually been with us since the beginning of the season. Each nest was started by a single overwintered queen. However, this is the time of the season when the ever-expanding nests contain enough individuals for yellowjackets to start making their presence known … sometimes painfully.
All species of yellowjackets in Ohio build circular to oblong paper nests. The non-native German (European) (Vespula germanica) and Common (Vespula vulgaris) Yellowjackets build nests underground or occasionally in hollow trees, rock crevices, or crevices in buildings. The native Eastern Yellowjackets (Vespula maculifrons) build their nests underground and Aerial Yellowjackets (Dolichovespula arenaria) build exposed nests in trees, shrubs, or on buildings.
Yellowjackets are actually very important beneficial insects. I once watched yellowjackets totally decimate a colony of redheaded pine sawflies (Neodiprion lecontei) with the sawfly larvae being carried off one at a time to become meat items for yellowjacket larvae. From late-spring through the summer, the ever-expanding numbers of yellowjacket workers keep busy enlarging their nest and foraging for caterpillars, sawfly larvae, and other soft-bodied insects. They use their powerful mandibles to grind-up these protein-rich meat items to feed to yellowjacket larvae. The growing larvae must be feed a high protein diet in order to develop normally. Thus, throughout much of the season, yellowjackets are considered beneficial insects.
Of course, yellowjackets also have a deserving reputation for becoming a serious nuisance late in the season. Sometime in late-summer to early fall, drones (males) and new queens begin to develop in the nests. These new-comers do not require protein since they are not growing; they need energy from carbohydrates. So, they lounge around the nest begging the workers for sweets. In an effort to appease these freeloaders, the workers search for foods that have this much needed energy boost such as soda, donuts, and funnel cakes; the All-American fine cuisine we love to eat at county fairs! Thankfully for the over-worked workers, nest populations of adults begin to peak in the fall with 5,000 or more workers in the colony.
As fall comes to an end, the new queens and drones leave their nest to mate, and the queens seek protected overwintering sites. The colony from which they developed dies during the winter; yellowjacket nests only last one season. This means that you should avoid declaring war on a yellowjacket nest unless its located where it presents a serious stinging hazard. The nests will eventually die-out on their own; with no fanfare for the poor overworked workers.