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Entomologists across the country have spent the last few days fielding calls and emails from concerned citizens about “murder hornets.” While the detection of the Asian giant hornet, Vespa mandarinia, in Washington is alarming to beekeepers and citizens in the Pacific Northwest, it is important to understand that the insect has not been found in Alabama.

In December 2019, a Washington resident found a large, dead hornet that was confirmed as an Asian giant hornet. This marked the first detection of the pest in north America.  Additionally, four more reports have been confirmed in Washington. The United States Department of Agriculture, Washington State Department of Agriculture and local universities are already working on public education, surveys, and eradication methods. Their goal is to eradicate the pest before it becomes established.

Description

Asian giant hornets are the world’s largest hornet measuring 1.5-2 inches in length. They have very unique coloration that makes them distinguishable from other hornets. Their large head is orange or yellow with prominent eyes and they have a black and yellow-striped abdomen.

Pest Biology

Asian giant hornets are the largest hornet in the world and native to Asia. They are social insects and maintain underground colonies with one queen and multiple workers. These nests are difficult to locate. Nests are often formed in pre-existing holes in the ground, such as rodent’s nests. V. mandarinia will also nest in hollowed out tree trunks or the roots of dead trees.

Similar to fire ants, the queens are the backbone of the colony. With the ability to disperse and produce offspring, solitary queens begin a nest and then populate it with workers. The key to controlling a colony is to kill the queen.

Asian giant hornets are predatory insects. They feed on a variety of arthropods, including scarab beetles, long-horned beetles, spiders, and caterpillars.

As social insects, they can carry out coordinated attacks against the nests of other bees and wasps. These group attacks usually occur late in the season as their nests become large and they need food. They will “slaughter and occupy” the nests of yellow jackets, paper wasps, and honey bees.

They prefer honey bees as food because they cannot defend themselves against Asian giant hornets. Additionally, honey bee hives offer a bounty of food and are full of protein and fat.

Potential Threat

Asian giant hornets pose a threat to European honey bees in the United States. While they do prey on other arthropod species, we are most concerned about honey bees because of their value as pollinators and honey-producers. Beekeepers across all states should be informed about this pest and the progress on eradication efforts.

Will They Attack Humans?

If their colony or food are threatened, Asian giant hornets will attack. But it’s important to remember that they are not typically aggressive towards humans. Many people are familiar with honey bee stings; the short, barbed stinger becomes lodged in your skin and only allows for one sting.

The stinger on V. mandarinia is much larger and contains more venom than that of other bees. Its stinger has a curved shape with less barbs to allow for easier entry. This also means they can sting more than once.

For beekeepers, the average beekeeping suit will not protect you from this pest. Anyone with an allergy should take extra precautions around any bees or wasps and seek medical attention if needed.

It is important to stay informed and remain calm when it comes to any type of bee or wasp. Remember, Asian giant hornets only become aggressive when their nest or food is threatened.

Common Look-alikes

While the giant hornet has been identified in Washington state, it has not been found in Alabama or anywhere in the southeastern United States. There are many other bees and wasps in Alabama that are look-a-likes. Now is a good time to brush up on your identification skills.

In Alabama, several species may be mistaken for Asian giant hornets because of their large size. European hornets are found sporadically throughout the state. Alabama is likely at the southern edge of their range. Similar to Asian giant hornets, European hornets will become aggressive if their nest is threatened but they are not known to be a threat to honey bees.

Cicada killer wasps are another species that can be mistaken for Asian giant hornets due to their large size. These wasps hunt cicadas, as their name implies. Cicada killers are not a threat to humans and are actually quite gentle, curious insects.

This picture shows the Asian giant hornet (A) next to the European hornet (B) and cicada killer (C). Photo: Matt Bertone, North Carolina State University

More Information

If you have a wasp of concern, please contact Dr. Charles Ray for proper identification.

For more detailed information on identification, biology, and control options, visit United States Department of Agriculture or the Washington State Department of Agriculture.

 

Featured image at top of page courtesy of Matt Bertone, North Carolina State University

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