Scientists currently recognize approximately 22 species of true hornets, all belonging exclusively to the genus Vespa. These large, predatory insects are a type of eusocial wasp. They are often noticed due to their imposing size and their habit of building communal nests from a paper-like material. This small number of recognized species contrasts with the vast diversity seen in other insect groups.
Defining the True Hornets: The Genus Vespa
True hornets are defined taxonomically as members of the genus Vespa. This sets them apart from the many other large wasps mistakenly called “hornets,” such as the bald-faced hornet (Dolichovespula maculata), which is actually a type of yellowjacket. A reliable distinguishing characteristic is the large space, known as the gena or cheek area, between the lower margin of the eye and the base of the mandible.
All Vespa species are eusocial, living in complex colonies with a single queen, workers, and males. They construct nests by chewing wood fibers and mixing them with saliva to create a papery pulp. Many species build exposed, spherical nests in trees or shrubs. Others, such as the Oriental hornet (Vespa orientalis), prefer sheltered locations like underground cavities or tree hollows. Female workers possess a stinger and venom apparatus, which they use for defense and to subdue prey.
The Global Distribution of Hornet Species
The global distribution of the 22 Vespa species is remarkably concentrated, with the majority native to East and Southeast Asia. This region, spanning temperate and tropical zones, represents the evolutionary home for nearly all true hornet diversity. Only a few species naturally extend their range beyond Asia into other continents.
The European hornet (Vespa crabro) is the most widely distributed species. Its native range extends across Europe, into Russia, and parts of northeastern Asia. This species was accidentally introduced to North America in the mid-19th century and is now established across the eastern continent. The Oriental hornet (Vespa orientalis) has a natural range that reaches into Europe and North Africa. Most Vespa species are endemic, or restricted, to their native Asian habitats.
Profiles of High-Interest Hornet Species
Two Vespa species have garnered public attention due to their invasive potential and impact on honeybee populations. The Asian Giant Hornet (Vespa mandarinia), also known as the Northern Giant Hornet, is the world’s largest hornet; queens sometimes reach 5.5 to 6 centimeters in length. Its native range covers temperate and tropical East Asia, but it gained notoriety after brief detections in western North America.
This species is identifiable by its large, matte orange-yellow head and a robust body with banded yellow and brown segments. Vespa mandarinia is an apex predator specializing in group attacks on colonies of other social insects, including honeybees. A small group can quickly decimate an entire hive to harvest larvae. Their nests are predominantly subterranean, often utilizing pre-existing tunnels or spaces around tree roots.
The Yellow-legged Asian Hornet (Vespa velutina) is known for its rapid invasive spread across Europe. This hornet is smaller than Vespa mandarinia, measuring between 2 to 3 centimeters. It is visually distinct with a mostly dark, velvety-black abdomen and bright yellow leg tips. Its native range stretches from Pakistan across China and into Southeast Asia.
Since its introduction to France in 2004, Vespa velutina has become a serious pest for beekeepers across Europe. This hornet uses a “hawking” strategy, hovering outside a beehive entrance to catch returning forager bees. This behavior causes stress to the colony and can lead to its collapse. Both Vespa mandarinia and Vespa velutina are examples of the predatory threat hornets pose to apiculture when they are introduced outside of their natural ecosystems.