State makes discovery about Asian giant hornets eradicated in 2021

Any Asian giant hornets that may still be in Washington would be hibernating right now, but there is no winter rest for the state researchers who are busy learning about them.

That research led state entomologists to an important discovery about the origin of the hornets that were eradicated this past year.

Since the hornets were first discovered in 2019, the Washington State Department of Agriculture has eradicated four nests — one in October 2020, and three in summer 2021. All of the nests were located within a few miles of each other, east of Blaine.

Each fall, as the hornets in the old nest die off, queens mate and fly off to start new nests. After the winter hibernation, new hornets start emerging in the early summer.

Asian giant hornet season wraps up after no sightings in three months

Now, WSDA says DNA testing has shown that all three nests destroyed in 2021 were related to the nest eradicated in 2020.

Last year we took DNA samples from several specimens from each of the three #AsianGiantHornet nests that we eradicated. We were able to determine that all three 2021 nests were related to the 2020 nest. pic.twitter.com/IYwvrz0CGT

— Washington State Department of Agriculture (@WSDAgov) January 12, 2022

This means that the nests were not started by some unknown group of Asian giant hornets that the state has yet to discover. Instead, WSDA determined that some queens must have escaped the 2020 nest in the days before it was eradicated.

This latest news does not rule out the possibility of other undiscovered hornet nests in the area. At the end of 2020, entomologists suspected that there was at least one nest still in the Blaine/Birch Bay area. If there indeed was, then that nest could have produced queens that could have founded new nests in 2021 — and those nests could have produced new queens to continue the cycle this year.

Still, no hornets were seen in Washington after the third 2021 nest’s eradication in September — what would typically be prime season for hornet spotting. That has entomologists cautiously hopeful, but not counting their chickens — or hornets — yet.

The department has told KIRO Newsradio that even if no new hornets are found in 2022, it would be too soon to declare victory; the state would need to go years without a hornet sighting to officially say the hornets are eradicated.

Any 2022 hornets will likely start emerging around the start of July. Members of the public are invited to make their own hornet traps and report any discoveries to WSDA.

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