Paws for Thought: What’s the buzz on the “murder” hornet?

The giant Asian hornet, or ‘murder hornet’ as they’re also known in common parlance. Shutterstock

EDITOR’S NOTE: Dr. Janice Mitchell is a veterinarian with Island Animal Hospital and Little Current Veterinary Services.

What’s the buzz on the “murder” hornet?

by Dr. Janice Mitchell

This month’s column will be a different twist from the four-legged creature variety to a public interest story involving the winged insect variety. Since veterinarians are now becoming involved with the health management of the honey bee, any threat to their management is duly noted. This article will focus on the media sensationalized ‘murder’ hornet and give a little more detail about the giant Asian hornet. Information about this non-endemic hornet has been made available to beekeepers through OMAFRA Provincial Apiarist Paul Kozak.

The giant Asian hornet, Vespa mandarinia, is native to temperate regions of Asia, including northern India, China and Japan. It is the largest hornet species in the world. The queen hornet can exceed 4.5 cm in length, and the female workers range from 2.5 to 4.0 cm.

They are identified by their noticeably (and striking I might add) large orange heads and black eyes—you have probably seen their mug shot on the Weather Network. Nests are usually constructed in a cavity in the ground, although they also may occupy a cavity in a tree. Typically, in late summer and fall, hornets begin to prey on honey bees at their nests. An individual hornet can grab and kill dozens of worker honey bees that it then carries back to its nest, chews up and feeds to its larvae. Additionally, a hornet may return to its nest and recruit nest mates to the bee hive it has located. Over the span of a few hours, several dozen hornets may have killed the entire honey bee colony (20,000-30,000 bees) and take over the hive, consuming the larvae and honey for days after. Interestingly, the destruction wrecked by this hornet occurs mainly to the Westernized European honey bee (Apis Mellifera) yet not so much with the wild Japanese honey bee (Apis Cerana Japonica). The Japanese honey bee has co-evolved with this giant and is able to defend its colony much more successfully than its European counterpart who knows no defence mechanisms. The Japanese bees will actually heat a hornet to death by smothering it!

The giant Asian hornet can also be a painful threat to humans, companion animals and livestock who may disturb and accidentally walk on its nest, similar to any other hornet. The normal beekeeper protective suits are not protective against their sting as a much thicker material would be needed to be preventive. Apparently, the sensation caused by an encounter with these insects is described as “having red hot thumbtacks driven into the flesh,” according to a BC entomologist and beekeeper involved in the Nanaimo hornet covert ‘sting’ operation.

The good news is that there are no reports of this hornet in Ontario. The only detections in North America have been in BC (August 2019 Nanaimo and November 2019 White Rock) and Washington State. If V. mandarinia gets a toe-hold in North America it could be very difficult or impossible to eradicate. It is thought that it will have an impact on honey bee populations in North America however the degree is not known. It may do well in parts of North America south of BC, however it is not known how hardy it will be for other areas with a more typical Canadian winter. It is not thought to spread by honey bee colonies, but rather equipment or transportation—trucks and freight.

As a result, plans are currently being made to monitor the presence of these wasps in BC, working with various agencies and organizations including local government and beekeeper associations. The BC monitoring program currently being developed includes baiting these hornets and then catching them. The nests will be located by following caught hornets that have been marked by either attached streamers or those that have been radio tagged. The nests will then be eradicated using carbon dioxide. Local beekeepers are also requested to monitor their colonies closely for hornet visits and help track the spread of the giant hornet by following the “slap, snap, zap and wrap” method. If one can do so safely, Canadians who think they’ve encountered the insect are to kill it by slapping it with a stick, snapping a photo and then “zapping” it in an email to the Invasive Species Council of BC, followed by wrapping it in plastic and freezing it in case a sample is needed. As well, the CFIA Plant Health group are putting together a border lookout for Canadian Border Services Agency to carefully inspect stages of hornets mostly from the East—Asia and Russia.

For the Joe Shorthouses out there (kudos to our paper’s contributing entomologist), I recommend the informative following documentary, by BBC’s Natural World titled ‘Buddha Bees and the Giant Hornet Queen.’ I promise you it is more interesting than Netflix’s ‘Tiger King.’