It is easy to confuse the various stinging insects that frequent backyards, often leading to inaccurate labeling of any black-and-yellow flier as a “bee” or “hornet.” Accurately identifying these insects, particularly the aggressive yellow jacket, is important for safety and management. Understanding the specific differences in their appearance and behavior is the first step toward reducing unwanted interactions and potential stings.
Yellow Jackets Are Wasps
A yellow jacket is a type of wasp, and a hornet is also a type of wasp; both belong to the family Vespidae. Yellow jackets are social wasps categorized under the genera Vespula and Dolichovespula. The term “wasp” is a broad designation for insects in the order Hymenoptera that are neither bees nor ants.
Hornets belong to the genus Vespa. All hornets are wasps, but not all wasps are hornets, and yellow jackets are separated from hornets at the genus level. These differences in genus result in observable distinctions in size, appearance, and behavior. The common name “hornet” is sometimes misapplied, as the bald-faced hornet is actually a black-and-white species of yellow jacket (Dolichovespula maculata).
Visual Differences Between Yellow Jackets and Hornets
Size is one of the most noticeable differences, with yellow jackets being significantly smaller than true hornets. Yellow jackets typically measure about one-half inch (12 mm) in length, featuring a compact, sleek body. True hornets, such as the European hornet, are much larger, often growing to over one inch (25 mm) long.
Yellow jackets are characterized by bright, sharply defined yellow and black banded coloration. Many species have distinct black markings on their first abdominal segment. True hornets often display different coloration; for example, the European hornet has a combination of reddish-brown and yellow markings.
The yellow jacket exhibits a distinct, narrow “wasp waist” or petiole. Hornets, in contrast, have a more robust, fuller body and a broader thorax. The hornet’s head size is typically larger relative to its body, contributing to its more substantial and rounded appearance.
Contrasting Nesting and Temperament
The location and structure of their nests offer a clear distinction between the two types of social wasps. Yellow jackets build covered nests underground in abandoned rodent burrows or within enclosed spaces like wall voids and attics. Their nests are often hidden from view, with only a small entrance hole visible. Hornets, including the bald-faced hornet, construct large, enclosed, football-shaped paper nests that hang suspended from tree branches, eaves, or shrubs.
Yellow jackets are omnivorous and known for scavenging, which makes them a nuisance at outdoor activities. They are attracted to proteins (meats) and sugars (soda, fruit). Their aggressive pursuit of these resources peaks in late summer and fall as their colonies grow and food becomes scarcer. Hornets, by comparison, are primarily predatory, focusing on hunting other insects, and are less likely to scavenge.
Yellow jackets are considered the more aggressive and persistent of the two, especially when their nest is disturbed. They vigorously defend their territory and can sting multiple times without losing their stinger. While hornets are less aggressive when foraging, they are fiercely territorial and will mount a strong defense if the nest is directly threatened.