OLYMPIA, Wash. — More than 500 Asian giant hornet specimens in various stages of development were collected when entomologists found the first Asian giant hornet nest in the United States.
But finding the nest was just the first step in the eradication. After the discovery of the nest site, WSDA entomologists had to safely remove hornets living in the nest, remove the tree, and finally split the tree open to reveal the nest inside.
After opening the tree containing the Asian giant hornet nest on Oct. 29, WSDA entomologists still had a lot of work to do to collect data about what the nest contained. Much like the election, the tallying took quite a bit of time and, to some extent, continues.
The nest was just over 8 feet high in the tree and, once opened, was found to be about 14 inches long and 8 to 9 inches wide. Here are the preliminary results of what our entomologists found in the nest.
- 6 combs – There were six layers of comb in the nest. Combs are the structures that hold the hornet larvae as they develop. Part of the interior of the tree had been chewed away to accommodate the combs.
- 776* cells – The combs are made up of cells and each individual cell can hold a developing Asian giant hornet. *This number is approximate as there was some damage to the combs.
- 6 unhatched eggs – These eggs were all located in the last and smallest of the combs.
- 190 total larvae – The larvae are whitish “grubs” in uncapped cells. Many had fallen out of the combs into the tree cavity during the nest removal.
- 108 capped cells with pupae – Pupae are the next stage after larvae. Based on the size of the cells, most of the pupae found are believed to be pupae of new virgin queens.
- 112 workers – This total includes 85 workers that were vacuumed out of the nest on Oct. 24. All of the workers survived being vacuumed out of the nest.
- 9 drones – Drones are male hornets and they generally emerge from the nest before the new queens emerge.
- 76 queens – Most likely all but one queen would 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.
Despite multiple applications of carbon dioxide, removal of the workers, and storage in a cold facility, most of the specimens were still alive when the nest was opened.
Where we go from here
WSDA will continue trapping through at least Thanksgiving and possibly beyond, but will likely only track worker hornets. Our entomologists will not, for example, track new queens if any are captured as they are unlikely to return to a nest, but instead will attempt to locate a mate. Even if no other hornets were to be found, WSDA will continue to trap for at least three more years to demonstrate the area is free from Asian giant hornets.
WSDA’s Pest Program still hopes to eradicate Asian giant hornets from the Pacific Northwest in cooperation with our neighbors to the north in Canada. The effort will take require international cooperation, research for better detection tools, and the continued work of vigilant observers from the public to prevent Asian giant hornets from gaining a permanent foothold here.
If you may have seen an Asian giant hornet in Washington State, report it with a photo if you can get one at:
If you believe you have seen an Asian giant hornet but live in another area, please report it to your state or province’s invasive species managers.
— Washington State Department of Agriculture
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