Whatcom nest had 500 Asian giant hornets in stages of growth

By Kie Relyea / The Bellingham Herald

The first Asian giant hornet nest found in the U.S. contained more than 500 of the hornets in various stages of development, Washington state scientists revealed on Tuesday, Nov. 10.

That number included 76 live queens that emerged after the small nest — discovered in the cavity of a tree southeast of Blaine — was vacuumed out late last month, with all but one likely to be new, virgin queens.

“New queens emerge from the nest, mate, and then leave to find a place to overwinter and start a new colony the next year,” said Karla Salp, spokesperson for the Washington State Department of Agriculture, in a blog post prior to a scheduled briefing on the state’s efforts to find and destroy the hornets.

The percentage of mated queens who would go on to start their own colonies is small, according to Sven Spichiger, managing entomologist for the state agency, during a virtual media briefing on Tuesday that delved into what scientists found when they opened the nest in late October.

When they opened the nest, scientists also found 108 white-capped cells with pupae, which are the next stage after larvae. Based on the size of the cell, they believe those contained new queens waiting to emerge.

Knowing that a small nest had the ability to produce nearly 200 queens had the nest not been destroyed had Spichiger saying, “As far as we can tell, we got there just in time.”

The state agency is continuing its efforts to keep the invasive hornets — possibly introduced to Whatcom County via a mated queen who came here because of international trade — with an appetite for honeybees from gaining a toehold in the Pacific Northwest.

Other things entomologists found during their preliminary analysis of the 14-inch-long nest included:

• Six combs stacked on top of each other and holding developing hornet larvae. Part of the inside of the tree was chewed away to accommodate the combs, according to Salp.

• The combs contained an estimated 776 individual cells. Each cell can hold an Asian giant hornet as it develops. The number of cells is estimated because there was some damage to the combs when the nest was vacuumed to destroy it.

• A total of 190 larvae, which look like whitish grubs in uncapped cells.

• 112 worker hornets, including the 85 workers that were vacuumed from the nest on Oct. 24. All the vacuumed hornets survived.

• Nine drones, which are male. They usually emerge from the nest before the new queens do.

The hornets’ native range is northern India to East Asia, according to the U.S. Department of Agriculture.

In their native range, Asian giant hornet nests have as many as 4,000 cells and can produce up to 800 queens, Spichiger said.

Popularly known as “murder hornets,” Asian giant hornets were first reported in Whatcom County on Dec. 8, 2019, representing the first detection in Washington state and the U.S.

The state’s entomologists located the small nest near a wooded area off of Burk Road, southeast of Blaine, on Oct. 22, after they captured live hornets earlier in October, tied radio trackers on them and followed one back to its home in the cavity, about 8 feet up the tree.

They destroyed the nest by vacuuming it out on Oct. 24.

The tree was then cut down and the section that contained the nest was taken to the Washington State University Puyallup Research and Extension Center on Oct. 29 for further study.

The state has been working to trap the hornets and find their nests to prevent the hornets from spreading outside of Whatcom County to the rest of Washington and the U.S. The hornets also have been found just over the Whatcom County border, in British Columbia, Canada, including in Langley in spring and, most recently, Abbotsford on Nov. 2.

Spichiger believes there are other Asian giant hornet nests in Whatcom County, based on previous trapping results.

Up to 2 inches long, the Asian giant hornet, or Vespa mandarinia, is the world’s largest hornet species. They are identifiable by their large yellow/orange heads. Their native range is Asia.

The hornets are known for their painful stings. They can sting multiple times and their venom is delivered at a larger dose. They will attack people and pets when threatened, such as when someone walks into their nest.

“These are not going to hunt you down and murder you,” Spichiger said.

The hornets usually nest in the ground.

People should be extremely cautious near them, agriculture officials said, and those who have allergic reactions to bee or wasp stings should never approach an Asian giant hornet.

The hornets are feared for the threat they pose to managed honeybees and, by extension, the valuable crops in Washington state that the bees pollinate. They also prey on local pollinators such as wasps, posing a threat to the local ecosystem.

When Asian giant hornets are in their slaughter phase, which they’re believed to be in now, they mark a honeybee hive, attack it, use their powerful jaws to decapitate the bees, and take the bees’ young to feed their own. A few hornets can kill 30,000 honeybees and take out a hive within hours, and managed honeybees here have no defense against them, Spichiger said in a previous Bellingham Herald article.

There have been no reports of honeybee hives being attacked in Whatcom County this year.

State agriculture officials will continue to trap through Thanksgiving at least.

Report hornets

People who believe they have seen an Asian giant hornet in Washington state, can report it at agr.wa.gov/hornets, which is preferred, and hornets@agr.wa.gov, or by calling 800-443-6684.

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