Yellow jackets are social insects known for their distinct black and yellow markings and their predatory nature. These wasps live in organized colonies that grow significantly throughout warmer months. While they play a role in controlling pest insect populations, their tendency to scavenge near human activities, especially in late summer, often leads to unwanted encounters. Understanding their nesting habits is helpful for avoiding these common nuisances.
Common Nest Sizes and Appearance
Yellow jacket nests begin as small structures, about the size of a golf ball, established by a single queen in the spring. As the colony grows, these nests can expand considerably, reaching the size of a soccer ball or basketball by late summer. Some mature nests can become even larger, occasionally exceeding two feet in diameter. Internally, a mature colony can contain several thousand individuals and up to 15,000 cells for rearing young.
Nests are constructed from a papery material created by chewing wood fibers and mixing them with saliva. This gives them a characteristic gray or brownish, wavy texture. Inside, they feature multiple horizontal tiers of combs, similar to honeybee combs, where larvae are reared. These comb layers are encased within a protective outer envelope, regulating internal temperature and humidity.
Where Yellow Jackets Build Nests
Yellow jackets exhibit diverse nesting preferences, with some species favoring subterranean locations and others constructing aerial nests. Many species, such as the Eastern yellowjacket, commonly build their nests underground, often utilizing abandoned rodent burrows, tree roots, or other existing cavities in the soil. The entrance to a ground nest typically appears as a small, inconspicuous hole, sometimes surrounded by excavated soil or pebbles. These underground nests can be difficult to spot until activity levels increase.
Other yellow jacket species, including the German yellowjacket and aerial yellowjackets, construct nests in protected aerial locations. These sites can include dense bushes, tree hollows, or within human-made structures such as attics, wall voids, eaves, and sheds. Aerial nests might be visible as a papery mass attached to a surface, or they may be hidden within a void, with only a small entrance hole indicating their presence.
Factors Affecting Nest Growth
The growth of a yellow jacket nest is influenced by several biological and environmental factors, primarily tied to their annual colony cycle. A single queen initiates the nest in spring, laying eggs that develop into the first generation of sterile female workers. These workers then take over the tasks of nest expansion, foraging for food, and caring for subsequent generations, allowing the colony to grow rapidly throughout the summer. The ultimate size of a nest is directly related to the number of workers, which can reach thousands by late summer.
Species diversity and the duration of the warm season significantly impact nest size; longer periods of favorable weather allow for more extended growth and greater worker populations. Abundant food, including protein and sugary substances, supports the development of more larvae and workers. In regions with mild winters, some colonies, particularly of the Southern yellowjacket, can persist for multiple seasons, leading to exceptionally large, perennial nests with tens of thousands of workers and multiple queens.