Asian giant hornets threaten both sides of the border

Jake Bodart, left to right, Austin Johnson and Jessica Rendon of the Oregon Department of Agriculture look at the advanced telemetry system used for tracking Asian giant hornets while wearing hornet extraction suits, during a hornet field training day held by the Washington State Department of Agriculture Pest Program near Blaine, Washington last month. |    Reuters/Lindsey Wasson photo

A British Columbia producer is keeping a watchful eye on her beehives after the recent discovery of three nests of Asian giant hornets just across the border in the United States.

Heather Higo said the nearest nest of the insects, which have gained international notoriety as “murder hornets,” was only about 500 metres from some of her hives near Langley, B.C.

“I wasn’t totally surprised, but I was disturbed… it’s not at the top of the list for my honeybee colonies, but it’s definitely something that’s kind of niggling at me all the time.”

The nests were found in Washington state, said Higo, who is also the president of the B.C. Honey Producers Association. She hasn’t personally encountered any of the hornets and she doesn’t view them as an overall problem for B.C.’s beekeepers.

However, she cautioned that could change over the years if surveillance and eradication doesn’t keep up with the potential spread of the insects.

“It’s my understanding that the Asian giant hornet is the fiercest of all the Asian hornets and has the greatest capability of destroying honeybee (colonies).”

They are the largest hornets in the world, with bodies of nearly five centimetres and wingspans of up to seven cm. The first Asian giant hornet nest was found in 2019 in Nanaimo, B.C., with a nest eradicated near Blaine, Wash., in 2020.

The Washington state Department of Agriculture said Sept. 11 it had eradicated two more nests this year, with plans underway to destroy a third nest.

Due to the fact beekeepers in B.C. are more involved with pollination than honey production, the hornets could at some point affect pollination services provided to the tree fruit and berry industries if beehives are attacked, said Higo. “I’m not foreseeing doom coming because I doubt that these Asian giant hornets are going to get to that level.”

They likely crossed the Pacific as accidental stowaways within goods potentially ranging from cars to pots transported on ships from Asia, said Paul Van Westendorp, provincial apiculturist for the B.C. Ministry of Agriculture, Food and Fisheries. They can decimate unprotected beehives, and their venom kills several people each year in countries such as Japan.

However, he doesn’t agree they’re murder hornets because the term greatly exaggerates their essential nature as predators of other insects.

“In general, they are totally uninterested in us and in our barbecue event.”

Not that it wouldn’t be a wise idea to avoid disturbing them if you’re near one of their nests, he added. Their proportionately large stingers aren’t barbed like those of honeybees, allowing them to repeatedly deliver venom at a larger dose than that of a yellowjacket wasp.

“We have special suits that we acquired that are designed with very large spaces between our skin and the outer layer of that suit… they can sting straight through your clothing otherwise.”

Despite such concerns, Westendorp doesn’t believe Asian giant hornets in general currently pose an acute risk to the livelihoods of beekeepers in B.C., describing their potential impact as “very little really.”

Their current population density on the West Coast is so low that they likely face problems finding unrelated mates, which is vital in maintaining their genetic diversity so they can survive in their new environment, he said. The hornets’ large heads also mean producers can design entrances that only let honeybees inside hives, he added.

However, genetic sequencing of specimens taken since 2019 has shown separate origins ranging from Korea to Japan for the Asian giant hornets discovered on the West Coast. A related species of hornet from Asia was also detected in Vancouver, said Westendorp.

Asian giant hornets prefer to nest within things such as cavities in deciduous trees, with the last three nests in Washington found inside alder trees. Westendorp said the trend is very encouraging because “it may offer the opportunity for us to narrow our search.”

The area in Washington where the latest nests were detected is forested, while habitats north of the border in B.C. tend to cultivated fields.

The spread of Asian giant hornets in the province will likely also be limited by B.C.’s mountain ranges, not to mention the semi-arid climate of areas such as the Okanagan Valley, he said. Regions further east, such as the treeless grasslands of the prairie provinces, likely aren’t suitable for the insects, he added.

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