Northern Giant Hornet

Northern giant hornets are well named as the world’s largest hornet. A queen’s body length can grow to exceed 5 cm (2 inches), the width of a driver’s license, with a wingspan that can exceed 7.6 cm (3 inches), the length of a driver’s license. Male and female workers look very similar but are smaller at 3.5 to 3.9 cm (1.5 inches) in body length.

Their colour is distinctive – you should look for orange-yellow heads, a black or dark brown thorax, and striped abdomens – with alternating bands of orange-yellow and black or orange-yellow and brown. The stinger region is entirely yellow. In North America, there are several native, naturalized, and invasive insects that are commonly confused with the northern giant hornet including the European hornet and eastern cicada killer.

Photo credit: Shirley Xanthe, USDA

After a long winter underground, the northern giant hornet queen emerges in late April to early May and begins to establish her new nest in the ground. The queen forages and performs all the work including constructing the nest, egg-laying, and caring for the young.

These tasks are then passed over to the first set of workers who emerge as early as June and take over the duties within two to four days. The queen then focuses solely on laying eggs while the workers focus on foraging, attending the queen, and constructing larger cells in the nest.

By the end of August through October, only the queens and males (drones) are reared. During this stage, the workers will start attacking other insects to meet the growing food demands of the colony. It is during this time that mating occurs and the founding queen of the nest dies. No new workers are emerging, and the nest begins to die out.

After this, inseminated queens search for their ideal location to overwinter and the cycle repeats in the springtime (Cobey S et al., 2020).

Photo credit: The Asian Giant Hornet: What the public and beekeepers need to know 

Northern giant hornet colonies nest underground together with one queen and many workers. Being underground, colonies are typically difficult to locate. They create nests underground in a variety of ways including digging, occupying pre-existing tunnels, and using spaces by tree roots.

In terms of the overall ecosystem this species prefers, they tend to gravitate towards low forests and mountains, and avoid high-altitude climates and plains (Pestworld.org).

Photo credit: Smithsonian Magazine

Since northern giant hornets nest below the surface, nest sightings are not common. Seeing the hornet itself will be the first sign that there is a potential outbreak.

Photo credit: Hanna Royals, Museum Collections: Hymenoptera, USDA APHIS PPQ, Bugwood.org

Proper identification and reporting can help with this, as they are commonly mistaken for native or naturalized hornets in Ontario such as the European hornet (Government of Ontario). The graphic above can be helpful in safely identifying these insects.

Northern giant hornets are native to Southern Asia, from India through China, into Japan and Korea. They are known for inhabiting the lower altitude forest and avoiding large plains and high-altitude regions. They have been found in the Nanaimo, BC area (August 2019) as well as south into Washington state (December 2019). Research is currently underway to track and identify whether the northern giant hornet will spread over the Rocky Mountains without human assisted movement.

The map below is the EDDMapS (Early Detection and Distribution Mapping System) distribution map for the northern giant hornet as of July 2021. To see the current EDDMapS distribution map, click on the map below.

Map from EDDMapS. 2021. Early Detection & Distribution Mapping System. The University of Georgia – Center for Invasive Species and Ecosystem Health. Available online at http://www.eddmaps.org/; last accessed July 28, 2021.