Dolichovespula maculata

Taxonomy

Order: Hymenoptera
Family: Vespidae
Subfamily: Vespinae
Genus: Dolichovespula Rohwer, 1916
Subgenus: Dolichovespula Rohwer, 1916
Species: Dolichovespula maculata (Linnaeus, 1763)
Common names: bald-faced hornet, bald hornet, white-faced hornet, black jack, white-tailed hornet, spruce wasp, blackjacket, and bull wasp

Background

Dolichovespula maculata, the bald-faced hornet, is a yellowjacket and not a true hornet. Its common name comes from its largely black color with a mostly white face and abdominal apex.

How to separate from Asian giant hornet

  • Bald-faced hornets can be larger than many other yellowjackets, but they are only about half as large as Asian giant hornets
  • They are mostly black with pale yellow to white markings
  • The face is pale yellow to white

Distribution

Dolichovespula maculata is found throughout most of the Nearctic region, except the central plains and desert southwest.

Distribution map of Dolichovespula maculata by GBIF: https://www.gbif.org/species/1311815

Diagnostic characteristics

D. maculata is easily recognized by its striking black and white coloration.

To identify the genus:

  • Hind ocelli separated from posterior margin of vertex by at most one ocellar diameter
  • Pronotal carina absent or broadly interrupted medially
  • Forewing length 8–18 mm (0.3–0.7 inches)
  • Malar space long, about twice mid-ocellar diameter
  • Without reddish markings on head and thorax

To identify the species :

Diversity

The genus Dolichovespula contains 18 species worldwide (Archer 2006). Four species are found in the Nearctic region, including D. alpicola, D. arenaria, D. maculata, and D. norvegicoides (Kimsey and Carpenter 2012).

Host/prey associations

Adults commonly visit flowers for nectar and other sugar sources such as ripe fruit. They are also scavengers of carcasses. Larvae are fed pre-chewed insects by the adult females.

Nesting and general behavior

The bald-faced hornet is found in forested areas or vegetation in urban areas. Nests are large and ovoid. Brood combs are enclosed in a spherical paper envelope. Nests are built above ground usually in trees and shrubs but also in protected sites, like under eaves and gutters. Nests have been found as high as 20 m (66 ft) above the ground (Archer 2006).

Fertilized queens overwinter in sheltered sites and begin nest construction around mid-May. Typically, the first workers begin emerging in mid-June, the first queens emerge by mid-August, and by mid-September the colony declines after producing males and new queens. The nest life cycle is approximately 4 months at higher latitudes and altitudes. At lower latitudes and elevations colonies may establish earlier and last longer (Archer 2006).

<p><em>Dolichovespula maculata</em>; photo by Dan Mullen, Flickr</p>
<p><em>Dolichovespula maculata</em>; photo by Dann Thombs, Flickr</p>
<p><em>Dolichovespula maculata</em>; photo by Judy Gallagher, Flickr</p>
<p><em>Dolichovespula maculata</em>; photo by Karen Hine, Flickr</p>
<p><em>Dolichovespula maculata</em>; photo by Judy Gallagher, Flickr</p>
<p><em>Dolichovespula maculata</em>, dorsal view; photo by Hanna Royals, USDA APHIS PPQ ITP</p>
<p><em>Dolichovespula maculata</em>, dorsal view; photo by Hanna Royals, USDA APHIS PPQ ITP</p>
<p><em>Dolichovespula maculata</em>, lateral view; photo by Todd Gilligan, USDA APHIS PPQ ITP</p>
<p><em>Dolichovespula maculata</em>, anterior view; photo by Todd Gilligan, USDA APHIS PPQ ITP</p>
<p><em>Dolichovespula maculata</em> (left) compared to <em>Vespa mandarinia</em> (right), dorsal view; photos by Hanna Royals and Todd Gilligan, USDA APHIS PPQ ITP</p>