Insect identification is a key skill for gardeners; learning the good guys from the bad guys helps your garden grow better. These picnic pests provide some benefits to the garden.
Eastern Yellow Jacket (Vespula maculifrons) Photo credit: Bill Johnson
Yellow jackets, or ground wasps, can be a real nuisance at the end-of-summer family picnic, but they get a bit of a bad rap. They are natural predators of caterpillars, grubs, grasshoppers and flies, all of which they feed to their larvae. Adults find their own sustenance in nectar, and while they are at it they pollinate flowers (though not to the extent that bees do, since they do not have pollen sacks). They take honeydew from aphid colonies; the presence of yellow jackets around trees and plants in late summer may tip you off to an aphid infestation.
Some people mistakenly refer to yellow jackets as bees, but they’re ground-nesting wasps. Unlike a lot of ground-nesting solitary bees, these wasps form colonies underground that can sometimes contain several thousand individuals. The workers and the males do not survive winter, but a new queen does. She emerges in spring to start a new underground home.
DON'T TRY THIS AT HOME!
When I was in high school, I wanted to see just how big a yellow jacket nest was. Late one fall, after the killing frosts had come, I decided to dig one up. To my surprise, it was a little bigger than a football and comparable to large bald-faced hornet nests that are seen hanging in trees. It contained layers of combs and quite a few dead wasps. I brought all of this into my folks’ basement and proceeded to pick through the debris. Suddenly I heard buzzing. I quickly realized that they were not dead yet—a few hundred yellow jackets were beginning to come to life in the warm basement. Well, they went back outside very quickly. The moral of this story: don’t do that at home. You also don’t want to disturb a colony by running over the nest entrance with a lawn mower. I’ve done that, too, and they become a bit testy.
Blackjacket wasp (Vespula consobrina), male. Photo credit: Bill Johnson
Ground wasps are found in the family Vespidae, the sub-family Vespinae and the genus Vespula. Three of the more common species found in the United States are the eastern yellow jacket (V. maculifrons), found in the eastern half of the country from Canada to Texas; the southern yellow jacket (V. squamosal), found from Michigan to Texas to Florida; and the black jacket (V. consobrina), which ranges across the northern states into Canada. Southern yellow jacket queens can be parasitic, taking over colonies of the eastern species. The black jacket can sometimes be confused with a bald-faced hornet, as they’re both black with white stripes.