Hornets are social insects that play a role in various ecosystems. They are significant predators, managing insect populations, including pests. Hornets also pollinate flowers and aid decomposition by recycling nutrients from dead insects.
Understanding “Ground Hornets”
The term “ground hornets” commonly refers to certain yellow jacket species (Vespula and Dolichovespula) that frequently build underground nests. It can also include digger wasps, like cicada killer wasps (Sphecius speciosus), or true hornets such as the European hornet (Vespa crabro) that nest underground. These insects often have black and yellow or black and white markings, though their sizes and social structures vary. While many yellow jackets form large social colonies, some ground-nesting wasps, like cicada killers, are solitary.
Preferred Habitats and Nesting Locations
Ground-nesting wasps and hornets favor areas with loose or sandy soil for excavation. These habitats include suburban lawns, gardens, flower beds, fields, and wooded areas. They also utilize existing cavities like abandoned rodent burrows, old tree roots, or hollows within stumps or logs.
Once a location is chosen, they modify it to create their nest. Yellow jackets, for example, expand abandoned burrows and construct paper-like nests from chewed wood fiber and saliva. Nests can also be found under railroad ties, concrete blocks, or within dense vegetation. Some species, like cicada killer wasps, create tunnels up to 10 inches deep with horizontal chambers for their brood.
Global Distribution
Yellow jacket species (Vespula and Dolichovespula), often called “ground hornets,” are widely distributed across the Northern Hemisphere. This includes North America, Europe, and Asia. For instance, the common wasp (Vespula vulgaris) and German wasp (Vespula germanica) are native to Europe and Asia but have established populations on other continents.
Introduced populations exist in New Zealand, Australia, and South America. In North America, the Eastern yellowjacket (Vespula maculifrons) and Western yellowjacket (Vespula pensylvanica) are common. Some Dolichovespula species, though often nesting aerially, can also be found in shallow subterranean situations across their northern hemisphere range.
Encountering Their Nests
Identifying a ground nest involves observing insect activity around a small, inconspicuous hole. The entrance may be about the size of a nickel, sometimes surrounded by a small, horseshoe-shaped pile of excavated dirt. Active nests show a constant stream of wasps flying in and out, often following a distinct flight path. A buzzing sound also indicates a nest, especially when activity is high.
If a ground nest is discovered, observe from a safe distance and avoid disturbing it. Approaching a nest, especially during the day when wasps are most active, can provoke a defensive reaction. For safety, any direct action, like treating the nest, is best performed at night when insects are less active and inside. Wearing thick protective clothing is recommended, and for large or problematic nests, contacting a pest control professional is the safest approach.