“Ground hornet” is a widely used term that often causes confusion, as it doesn’t refer to a single, distinct species. Instead, this common name typically describes various types of wasps that build their nests underground. Most frequently, people use “ground hornet” to refer to ground-nesting yellowjackets, which are common stinging insects. Understanding their true identity can clarify their behaviors and potential interactions.
What Are “Ground Hornets”?
The term “ground hornet” is not a formal scientific classification but a colloquial label applied to certain ground-dwelling wasps. It most commonly refers to yellowjackets, particularly species within the Vespula and Paravespula genera. These insects are identifiable by their distinctive black and yellow striped patterns. Yellowjacket workers typically measure about 0.5 inches in length and have smooth, hairless bodies with a narrow “wasp waist.”
True hornets, such as the European hornet (Vespa crabro), are distinct from yellowjackets. Hornets are larger, often reaching 1 to 1.5 inches in length, and typically display reddish-brown markings in addition to yellow. While hornets can be aggressive if their nest is disturbed, yellowjackets are often perceived as more aggressive, especially when scavenging. Another type of yellowjacket, the bald-faced hornet (Dolichovespula maculata), is black and white, and despite its name, is a type of yellowjacket, not a true hornet.
Characteristics and Behavior
Yellowjackets are social insects that live in organized colonies, featuring a queen, sterile female workers, and male drones. Their life cycle is annual, beginning in spring when an overwintered queen emerges to establish a new nest and lay eggs. The first generation of offspring develops into worker wasps, which then take over tasks such as nest expansion, foraging for food, and caring for the queen and larvae. As temperatures drop in the fall, new queens and males are produced, mate, and fertilized queens seek sheltered places to overwinter, while the rest of the colony perishes.
The diet of yellowjackets varies throughout the season. Early in the year, their primary food source consists of proteins, such as other insects and carrion, which they hunt to feed their developing larvae. As summer progresses into fall, their dietary preferences shift towards carbohydrates, leading them to seek sugary substances like nectar, ripe fruits, and human food and beverages. This scavenging behavior often brings them into close contact with people, particularly at outdoor gatherings where food is present.
Nesting Habits
The “ground” aspect of “ground hornet” refers to these wasps’ common nesting locations. Yellowjackets frequently build their nests underground, often utilizing abandoned rodent burrows, tree stumps, or other existing cavities in the soil. The entrance to an underground nest can be inconspicuous, appearing as a small hole in the ground. Inside, the nests are constructed from chewed wood fibers mixed with saliva, creating a paper-like material that forms multiple layers of combs.
These underground nests can expand significantly throughout the season, sometimes reaching depths of up to 1.5 feet. A mature colony can house thousands of worker wasps. While most yellowjackets nest underground, some species may also construct nests in other sheltered locations like wall voids or attics.
Stings and Encounter Safety
Yellowjackets are capable of stinging multiple times, a key difference from honeybees whose barbed stingers detach after a single sting. Yellowjacket stingers are smooth, allowing them to withdraw their stinger and deliver repeated injections of venom. A typical reaction to a yellowjacket sting includes immediate pain, localized swelling, redness, and itching at the sting site. This discomfort usually subsides within a few hours, though swelling and redness may persist for several days.
For some individuals, a yellowjacket sting can trigger a severe allergic reaction known as anaphylaxis. Symptoms of anaphylaxis can include difficulty breathing, hives, dizziness, and vomiting, requiring immediate medical attention. To minimize the risk of stings, remain calm and move slowly if a yellowjacket is nearby, rather than swatting at it, which can provoke an attack. Keeping food and drinks covered outdoors and properly disposing of trash can help deter these insects.