northern giant hornet

northern giant hornet, (Vespa mandarinia), species of social hornet (order Hymenoptera), the largest known wasp species in the world. Native to subtropical and temperate mountainous regions of Asia, including northern India, the Korean peninsula, and Japan, the northern giant hornet was introduced to North America in 2019. Sensationally dubbed the “murder hornet” by news media, the insect is able to swiftly destroy entire hives of western honeybees (Apis mellifera) and can inflict a painful sting.

Physical description

Northern giant hornets are approximately four times the size of domestic honeybees. While the queen can reach up to 50 mm (2 inches) in length, the bodies of female workers and male drones are generally somewhat smaller. The insects have a large solid yellow or orange head with large black eyes. Like other wasps, northern giant hornets have a narrow “wasp waist” that attaches its solid brown or black thorax to its abdomen, which is brown or black with yellow-orange stripes. The last segment on the abdomen is uniformly yellow-orange, and the insects are matte, not shiny, in appearance. They have a wingspan of approximately 76 mm (3 inches) with two pairs of yellowish wings. The workers have barbless stingers that are 6 mm (0.2 inches) long.

Life cycle and biology

Each spring a lone, fertilized queen emerges and feeds on tree sap, having overwintered in soil, straw, or rotting wood. She soon builds a nest in an appropriate nesting site, often in a tree cavity or in an underground cavity dug by another animal, and lays eggs; giant hornets rarely build nests in human structures. Once the eggs hatch, the queen cares for the young, feeding them a varied diet of tree resin, insects, and spiders, which she hunts and forages for near her nest. When the young colony has about 40 workers, the workers take over the hunting and foraging duties, and the queen permanently stays in the nest to continue laying eggs to further grow the colony.

In the late summer or early fall, the founding queen dies as the male drones and next year’s queens hatch. To feed these essential larvae, the workers forage for tree resin, nectar, honey, soft fruits, and mushrooms and hunt for beetles, other insects, and spiders. They are known to attack colonies of wasps and bees, including honeybee hives, and take the high-protein larvae and pupae back to their nest for the males and future queens. Upon reaching maturity later in the fall, the males leave the nest and wait for the young queens to emerge about a month later. The new queens mate with the males and then find an appropriate site to overwinter. The rest of the nest eventually dies as colder weather sets in.

Having coevolved with the predators, the Eastern honeybees (Apis cerana) of Asia can defend themselves against northern giant hornets. If a hornet worker enters their hive, they surround it until it is at the center of a ball of bees, at which point the bees buzz and flap their wings to generate enough heat to kill the hornet. However, domestic honeybees, which are widely used in agriculture around the world, have no such defense against novel northern giant hornets. The hornets can destroy a domestic honeybee hive in a matter of hours, killing the adult bees and taking the immature bees back to their nest for food. Given their deadly power, the appearance of northern giant hornets in North America sparked fears that the destruction of colonies of domestic honeybees could negatively affect agriculture and the U.S. economy.

Risk to humans

The long stingers of northern giant hornets can pierce protective clothing, including beekeeper suits, and they deliver venom that is more toxic than that of the bees and wasps native to North America. They do not lose their stingers and can thus sting repeatedly. The sting of northern giant hornets, like the stings of other hornet and bee species, can cause anaphylaxis—a potentially fatal allergic response—in humans. Even if a person is not allergic, the sting is extremely painful and can be crippling or deadly if a swarm attacks. However, northern giant hornets sting only if provoked. People are advised not to try to handle them or approach their nests. If the hornets are in the midst of attacking a beehive, they will attack beekeepers or others who try to interfere. Roughly 30 to 50 people die each year in Japan from northern giant hornet stings, usually due to allergic reactions.

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The northern giant hornet’s sting was not listed on the Schmidt sting pain index, a measure of the relative amount of pain that various insects of the order Hymenoptera (ants, bees, wasps, etc.) can cause humans.

History in North America

Northern giant hornets were first reported in North America in September 2019 on Vancouver Island, British Columbia, Canada. The hornets may have been accidentally transported in commercial shipping containers. In December 2019 the first northern giant hornet in the United States was found in Blaine, Washington, in the far northwest corner of the state near Vancouver Island. To protect European honeybees and their essential pollinator services, the U.S. Department of Agriculture’s Plant Protection and Quarantine program and the Washington State Department of Agriculture immediately began working to eradicate the species. A similar effort was also made in Canada. American scientists used radio trackers attached to northern giant hornets to locate and eradicate four nests. No hornets have been detected in either country since 2021. Samples of the hornets and part of “Nest Zero” (the first nest found in the United States) are preserved at the Smithsonian National Museum of Natural History in Washington, D.C.