Yellowjackets are a common group of predatory social wasps, typically recognized by their distinctive black and yellow striped bodies. These insects are often encountered during outdoor activities, particularly in late summer and early fall. Many species of yellowjackets build their nests in the ground, making them a common concern for homeowners and outdoor enthusiasts.
Ground Nest Characteristics
Yellowjacket ground nests are often subtle, appearing as a small, inconspicuous hole in the earth, frequently no larger than a nickel. These hidden entrances are typically found in existing cavities, such as abandoned rodent burrows, hollows under tree roots, or spaces beneath steps or dense vegetation. The ground provides natural insulation and protection for the developing colony. Often, the only visible sign of a nest is the steady stream of yellowjackets flying in and out of the single opening, sometimes along a consistent flight path known as a “bee line.”
Inside the ground, yellowjackets construct a paper-like nest from chewed wood fibers mixed with their saliva. This material forms multiple layers of hexagonal cells, similar to a honeycomb, which are enclosed within a protective paper envelope. The structure provides a secure environment for the queen to lay eggs and for the larvae to develop. As the colony grows, workers expand the nest deeper into the soil, creating a large underground structure that can house thousands of wasps by late summer. This subterranean location offers defense against predators and helps regulate the nest’s temperature.
Other Yellowjacket Nest Locations
While many yellowjacket species prefer to nest underground, not all of them do. Some species, such as the bald-faced hornet (which is a type of yellowjacket), build aerial nests. These nests are typically large, gray, football-shaped structures that are suspended from tree branches, shrubs, or eaves of buildings.
Yellowjackets can also establish nests in hidden cavities within man-made structures. Common locations include wall voids, attics, sheds, or even recycling bins. These nests, whether aerial or hidden within structures, have a similar internal architecture of paper cells. The choice of nesting site often depends on the specific yellowjacket species and the availability of suitable, protected spaces.
Seasonal Activity and Nest Dynamics
The life cycle of a yellowjacket colony is annual, beginning in the spring when a fertilized queen emerges from hibernation. She selects a suitable nesting site and starts building a small paper nest, laying her first eggs within its cells. Once these initial eggs hatch and mature into sterile female workers, they take over the tasks of foraging, nest maintenance, and expansion, allowing the queen to focus solely on reproduction.
Throughout the summer, the colony experiences rapid growth, with worker populations steadily increasing. Activity levels peak in late summer and early fall, when the colony reaches its largest size, often numbering in the thousands. This increased population density leads to more frequent human encounters, especially as food resources become scarcer. Yellowjackets become aggressive in defending their nests during this period, stinging repeatedly if threatened or their nest is disturbed.