Yesterday, will taking our Thanksgiving scraps to the compost bin, I stirred up a colony of yellow jackets, a type of wasp. Their presence took me by surprise since we have had several hard freezes along the Colorado Front Range.
In the Temperate zone of North America, yellow jackets are primarily of the eastern or German species; the latter is more aggressive, often stinging humans and other animals that come close to their nest site. The latter is placed in a cavity or underground chamber; there, the queen constructs the initial cells (using wood fibers) and begins to lay eggs. Male offspring are drones, remaining in the nest cavity, caring for the queen and fertilizing her; males die after mating. Female offspring are workers, scouring the regional environment for sugars, protein (insects, carrion, garbage) and wood fibers to enlarge the nest; protein is fed to the larvae while sugars are consumed by the workers, drones and the queen. At the peak of summer activity, the colony may contain up to 3000 individuals, a few of which will become queens; impregnated, the latter put on fat during autumn in order to survive the winter.
As winter grips the area, the workers and original queen die off and the new queens overwinter in a protected site; by late spring, they will emerge and establish new colonies, renewing the annual cycle. In tropical or subtropical regions, yellow jackets survive the winter and the nest can become massive; here in Colorado, that will not happen but yesterday's encounter was just another reflection of our unusually warm autumn weather.