The Asian giant hornet, a.k.a. the Murder Hornet, has arrived. Bees beware.

A giant, bee-killing insect dubbed the “murder hornet” is making inroads in the United States, threatening crops that depend on pollination, and humans who may get in its way.

The Asian giant hornet, Vespa mandarinia, is native to places like Japan, South Korea, and Taiwan, but was detected in Washington state late last year. Canadian officials also found the hornet in British Columbia in August.

The menacing orange-and-black hornets have workers that can grow an inch and a half long and queens that get up to two inches in length. They have a painful sting that can be fatal to humans — if they are allergic — and unlike most bees, hornets can sting more than once. Despite their name, however, people have little to fear from them: The British Columbia Ministry of Agriculture said that they “are not interested in humans, pets and large animals.”

Size comparison of bees and wasps
The Asian giant hornet, a.k.a. the Murder Hornet, is big.
Washington State Department of Agriculture

Instead, the main concern is what these hornets do to honeybees. With its spiked, dagger-like mandibles, an Asian giant hornet can decapitate 40 honeybees per minute. Within hours, a swarm of these invasive hornets can purge a beehive.

This voracious appetite for a critical pollinator poses a threat to key crops in the Pacific Northwest, where commercial beekeepers often rent their hives out to farmers growing crops like blueberries and raspberries.

The Washington State Department of Agriculture is now asking the public to report any findings of the hornet to keep track of its spread. It’s not clear how the hornets crossed the Pacific Ocean, but experts think they may have stowed away on a container ship or may have been deliberately imported as an ingredient in homemade purported performance enhancers.

The arrival of the murder hornet is just the latest woe for bees in the United States

Bees support about $20 billion worth of US agriculture each year, but are facing population declines around the world. Since 2006, US beekeepers have lost nearly a third of their colonies each year. Bees are under pressure from pesticides, habitat loss, disease, and invasive species like the Asian giant hornet. Several of these factors are likely at play in the rise of colony collapse disorder, which can leave bee colonies with no adult bees aside from the queen.

In Asia, bees do have a defense mechanism against the Asian giant hornet, however. They can swarm a scout hornet in the hive, forming a ball around the invader. Then the bees vibrate, causing the hornet to heat up, while carbon dioxide builds up inside the ball. The scout suffocates and dies, preventing it from relaying the coordinates of the hive to the rest of its swarm.

But it’s not clear whether bees in North America know how to deploy this technique since the hornet is a new threat. And with all the stresses bees already face, hives can only hold out for so long.


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