Yellowjackets are frequently misidentified as hornets or simply categorized as a general type of wasp, leading to confusion about their identity and behavior. The common name “yellowjacket” is often used broadly for any aggressive, black-and-yellow striped flying insect. Understanding the correct taxonomic relationship and the specific differences in appearance and habits is necessary for accurate identification. This clarification establishes the true nature of yellowjackets and their relationship to other stinging insects.
Yellowjackets A Wasp by Definition
All hornets and yellowjackets are types of wasps, belonging to the family Vespidae, which encompasses a wide array of social and solitary wasps, including paper wasps. Yellowjackets are specifically defined as predatory social wasps within the genera Vespula and Dolichovespula. These two genera fall under the subfamily Vespinae, which is commonly referred to as the hornets and yellowjackets. True hornets, in contrast, are exclusively members of the genus Vespa. The bald-faced hornet, despite its common name, is actually an example of a yellowjacket, belonging to the genus Dolichovespula.
Separating Yellowjackets from True Hornets
Distinguishing a yellowjacket from a true hornet requires focusing on specific physical characteristics, as their size and coloration offer the clearest clues. Yellowjackets are generally smaller, typically measuring around one-half inch to one inch in length. They possess a compact build with a very distinct, narrow “wasp waist,” and their bodies are smooth and shiny. True hornets, such as the European hornet, are noticeably larger, with some species reaching over one inch and sometimes up to 2.2 inches long.
They have a more robust, stocky build and broader thoraxes than yellowjackets. Their coloration is characterized by sharply defined, bright yellow and black bands, often featuring spade or anchor-shaped black markings on the first abdominal segment. Color-wise, true hornets often incorporate colors other than bright yellow and black, such as reddish-brown or muted brown and yellow, which gives them a less vibrant appearance than yellowjackets. Another anatomical difference lies in the head structure, where yellowjackets have a shorter distance between the lower margin of the eye and the base of the jaw compared to the more elongated face of a true hornet.
Comparing Nesting Habits and Aggression
Yellowjackets build concealed nests, most frequently underground in abandoned rodent burrows or within structural voids like wall cavities. Some yellowjacket species, such as the bald-faced hornet, construct large, gray, football-shaped aerial nests hanging from trees or buildings. True hornets, such as the European hornet, are more inclined to nest in protected, elevated cavities like hollow trees, barns, or attics.
A major behavioral distinction relates to diet. Yellowjackets are opportunistic scavengers, and their attraction to human food, such as sugary drinks, fruit, and meat scraps, causes frequent late-season conflicts. This scavenging behavior peaks in late summer and fall, making them appear aggressive around people.
Hornets, conversely, are primarily hunters that feed their larvae on large insects and are generally less interested in human food waste. While both insects will fiercely defend their nests, yellowjackets are considered more unpredictable and aggressive when away from the nest. The ground-nesting yellowjackets are particularly problematic because their nests are easily and accidentally disturbed by routine activities like mowing or walking.