Asian giant hornets, which picked up the name “murder hornets” when they made headlines across the U.S. earlier this year, are probably less imposing that previously reported, according to a Penn State expert in insects.
Among the most alarming notes reported about Vespa mandarinia – the scientific name for the hornet which doesn’t yet have an official common name in North America – was the fact that about 50 people die from its sting each year in its native range of eastern Asia.
“This statistic often is alarming for people, but for perspective, an average of 62 Americans are killed every year by bees and wasps for the same reasons,” said Michael Skvarla, assistant research professor of arthropod identification in Penn State’s College of Agricultural Sciences.
“From 2000 to 2018 in Japan, where these wasps are most common and abundant, an average of 21 people died per year from all wasp, hornet and bee stings combined, with Asian giant hornets accounting for only a subset of those deaths.”
Asian giant hornets, like other social wasps, can be defensive when they feel their nest is threatened or when they are defending a food source. He said, stings from the insect, when they do occur, are extremely painful. “However, they don’t seek people out just to sting them for no reason like some human-hating guided missile.”
The venom of Asian giant hornets isn’t even as lethal, on a per volume basis, as that of some native wasps, according to Skvarla. However, Asian giant hornets are large and deliver a proportionally large volume of venom per sting.
“That being said, it’s not clear that Asian giant hornets are ‘more deadly’ or more likely to induce an allergic reaction than honey bees, yellowjackets and other social wasps,” he said, “although there is a forthcoming paper that summarizes what little we know from the medical literature about Asian giant hornet stings.”
The large stinging insects, which were discovered last year in the state of Washington and the Canadian province of British Columbia, could be a concern for North American beekeepers if they become more widespread.
But, Skvarla said, the hornets are not an immediate concern in the northeastern U.S., including Pennsylvania, nor are they likely to be for a long time, if ever.
In the meantime, he suggested, it might be appropriate to tone down the discussions about the insect.
“The term ‘murder hornets’ originally was coined by a few Japanese media outlets several years ago, and a recent New York Times story using that description went viral, causing a bit of panic in the United States,” Skvarla said. “In their native range, they commonly are called ‘great sparrow bee’ in Japan, ‘tiger head bee’ in China and ‘general officer hornet’ in Korea.”
He explained that even the common name “Asian giant hornet” — its most frequently used moniker in English — could be confusing, because another large species, Vespa velutina, the yellow-legged hornet, is sometimes known as Asian hornet, and Vespa crabro, or European hornet, is sometimes called giant hornet.
Until the Entomological Society of America, which governs the use of common names for insects in the U.S., decides on the official designation for V. mandarinia, Skvarla contends that calling it sparrow wasp or sparrow hornet may be the best way to distinguish this species from others, since those names are similar to a name used in the wasp’s native range.
Whatever it’s called, much of the worry over the insect arises from its size. Asian giant hornet queens are among the largest wasps in the world and can grow to a length of more than 2 inches, with a wingspan of 3 inches.
“However, the queens are seen outside the nest only when they are hibernating or in the spring before workers have emerged,” he said. “Asian giant hornet workers can grow to 1.5 inches in length and are similar in size to some wasps that occur in Pennsylvania.”
Among wasp species found in eastern North America, the one most commonly confused with the Asian giant hornets is the European hornet, which is similar in size, shape and color. However, the two species can be distinguished. Asian giant hornets’ abdomens are banded yellow, black and brown, while European hornets’ abdomens are black toward the front and yellow toward the rear with rows of black teardrops.
Another species sometimes mistaken for the Asian giant hornet is Sphecius speciosus, known as the Eastern cicada killer. But, Skvarla pointed out, cicada killers have terminal abdominal segments that are completely black as opposed to Asian giant hornets’ yellow-banded abdomen. In addition, cicada killers lack any yellow on the head.
Unlike those other insets, Asian giant hornets are lethal to the honeybees and other insects upon which they prey. Japanese honeybees, which have co-evolved with Asian giant hornets, have defenses against them, but European honeybees — the species used in commercial honey production — are more vulnerable.
Individual hornets can kill many honeybees, discarding the heads, legs and abdomens and taking the protein-rich thoraxes back to the nest to feed the colony. Groups of three or more hornets can attack and decimate an entire honeybee hive.
“We’re not sure how Asian giant hornets might impact honeybees and American beekeepers,” Skvarla said. “Beekeepers in Asia have implemented a variety of strategies to combat the hornets. If this species becomes established and widespread in North America, some or all of these strategies potentially could be used here as well.”
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Contact Marcus Schneck at mschneck@pennlive.com.