Hornets are large eusocial wasps in the genus Vespa. There are 22 described species native to Europe and/or Asia. Several species have become established in other regions as well, such as Vespa crabro and V. orientalis, which have been introduced into North and Central America and even Madagascar.
The keys and information provided here focus on females, queens and workers. Males can be distinguished by having seven metasomal segments, no sting and 13 antennomeres. In addition, male antennaeantennae:
a slender moveable sensory organ located on the head above the clypeus
are longer and are never held coiled or strongly curved as they are in females. Queens are generally larger bodied than workers. Workers can be variable in body length, with smaller individuals found later in the season.
Diagnostic features focus on proportions of various body parts and coloration of the head, thorax and banding patterns on the metasomametasoma:
the posterior part of the body
. Structural features used to distinguish species include development of the genagena:
the cheek or side of the head
, relative positions of the ocelliocelli:
single facet light reception organs; on the top of the adult head
to the eye margins, clypeal shape and punctation, and thoracic punctation, particularly of the scutumscutum:
the largest segment on top of the thorax located between the wings and behind the head
and pronotumpronotum:
a collar-like segment on the thorax and directly behind the head; extends down the sides of the throax toward the first pair of legs
.
More information on hornet morphology can be found in Smith-Pardo et al. (2020) which provides a comprehensive illustrated key to the 22 species of Vespa.
Authors: L.S. Kimsey, J.M. Carpenter, E. Jochim, A.H. Smith-Pardo, A.J. Redford
Content last updated October 2023
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