The Washington State Department of Agriculture (WSDA) eradicated the first Asian giant hornet nest of the year on August 25.
The nest was located in the base of a dead alder tree in rural Whatcom County, east of Blaine. It was located about two miles from the nest that WSDA eradicated last October and about one-quarter mile from where a resident reported a live sighting of an Asian giant hornet on August 11. The site was also about one-quarter mile from the Canadian border.
WSDA staff began the eradication by vacuuming 113 worker hornets from the nest. Once the worker hornets were removed, the team began removing bark and decayed wood near the base of an alder tree at the entrance to the nest. Removing the wood revealed that the hornets had excavated the interior of the tree to make room for the nest, which consisted of nine layers of comb.
The portion of the tree with the nest was cut and transported to Washington State University Extension in Bellingham for further analysis. In addition to the worker hornets vacuumed from the tree, WSDA staff caught 67 additional hornets in the area with nets during the eradication. The nest itself had nearly 1,500 hornets in various stages of development.
“While we are glad to have found and eradicated this nest so early in the season, this detection proves how important public reporting continues to be,” Sven Spichiger, WSDA managing entomologist said. “We expect there are more nests out there and, like this one, we hope to find them before they can produce new queens. Your report may be the one that leads us to a nest.”
Anne LeBrun, National Policy Manager for Pollinator Pest Programs with the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service noted that successful cooperation between State and Federal agencies and members of the public is paying off in Washington. “We are pleased to play a role in this collaborative success by sharing technical expertise, providing financial support, and collaborating on survey and research efforts,” said LeBrun. “Public involvement remains an essential part of eradicating this hornet.”
WSDA will continue to trap for Asian giant hornets through the end of November. People who would like to set their own traps can find instructions on WSDA’s website. Those who suspect they have seen an Asian giant hornet should take a photograph if possible and visit agr.wa.gov/hornets to report the sighting.
The hornets were first detected in the United States in 2019 when a hornet was reported in Whatcom County. Asian giant hornet queens reach over five centimetres long and the slightly smaller workers are about four centimetres long. Giant hornets have an orange head and a dark thorax, and their abdomens are banded yellow, black and brown. They are a social species that lives in colonies. They typically build their nests underground, such as in abandoned burrows or cavities around tree roots. If they nest higher up, it is usually no more than two meters above ground. They are dormant over the winter and build a new nest each year.
Dubbed “murder hornets” by some, how dangerous are these giant insects? Well that rather depends on who you are. If you are a honey bee, you could be forgiven for calling them “murder hornets”. Asian giant hornets are not native to North America and they prey on honey bees and other insects. They can conduct mass attacks on honey bee hives, destroying the hive in a matter of hours.
What about us, can they really murder people? Emily Osterloff at the U.K.’s Natural History Museum says that Asian giant hornet venom is less toxic than that of other species, but they can inject more per sting and the stinger is long enough to puncture thick, protective clothing, such as the kind normally worn by beekeepers.
“This species will defend its nests. What can make them more dangerous than other hornet species is that they will attack as a group, recruiting other members of the colony to join in on the stinging. The quantity of venom they can inject through multiple stings can make them dangerous to young children as well as people with existing health conditions,” Osterloff says, adding that it is best for people to avoid their nests, but the hornets do not go out of their way to find humans to sting.
But ultimately, “Asian giant hornets are not murderous,” says Osterloff, “and negative nicknames like this risks unnecessarily giving rise to a wider dislike of them, as well as to insects more generally.”
So technically you could die if an Asian giant hornet, or more likely several, stings you, but in the U.S. you would be more likely to die from a sting from a more common wasp or bee. During 2000–2017, a total of 1,109 deaths from hornet, wasp, and bee stings occurred, for an annual average of 62 deaths, according to the Centers for Disease Control and Prevention. These deaths ranged from a low of 43 in 2001 to a high of 89 in 2017. Approximately 80% of the deaths were among males. None of the deaths were attributed to Asian giant hornets, nor have there been any reported deaths linked to the species since they were first recorded in the U.S.
Given the amount of things that can kill us, the “murder” moniker is perhaps a little unfair. Even so, it is important that the species does not become established in the U.S. A higher number of Asian giant hornets would of course increase the chances of being stung, which in turn increases the risk of fatalities. And the impact they would have on the natural ecosystem is certainly a cause for concern.