30 Japanese Hornets Massacre 30,000 Bees

Got you! Asian giant hornet with two honey bees

Five times bigger than your average European honey bee, the Japanese hornet is one of the insect world’s most feared predators. At 5 cm (2 in) long and with a wingspan of about 7.6 cm (3 in), there are not many insects that can get in its way. Though found throughout Asia, the Japanese hornet, a.k.a Asian giant hornet (Vespa mandarinia), is most common in Japan’s mountainous regions.

They’re huge – and not always this tame

The Japanese hornet’s stinger is about 6 mm (0.25 in) long and able to inject an especially potent venom that can even damage tissue or disintegrate human flesh. A Japanese scientist who got stung described the sensation as feeling "like a hot nail being driven into his leg.” Ouch!

Mincemeat again: Praying mantis victim

If stung by a giant hornet, treatment should follow soon after as even people can die from their stings. Though less toxic than honey bee venom, the Japanese hornets' toxicity is one of the greatest per sting because of the sheer quantity of venom injected. About 40 people die in Japan every year after being stung, mainly as a result of an allergic reaction to the venom.

Outrunning doesn’t work either as the hornets can fly at speeds of up to 40 km/h (25 mph) and travel distances of 97 km (60 miles) in a single day. Even an impressive predator in its own right like the praying mantis doesn’t stand a chance against the giant Japanese hornet.

Natural born killer: Vespa mandarinia

And the mincemeat comparison is really not far off. Not able to digest protein as such, the Asian giant hornet chews its prey into a fine paste with which it can then feed its larvae. They in turn produce a clear liquid that feeds the adults. Like a well oiled feeding machine.

As far as an attack on a honey bee hive is concerned, the Asian giant hornets’ strategy is simple: find, trace and attack with reinforcements. One hornet can kill about 40 European honeybees per minute – that means a hive of about 30,000 should take 30 hornets only about three hours! Once a hive is emptied, the hornets feast on the honey and carry the bee larvae back to feed their own.

Hornets ain't hiding from no one

But, the bees are not as defenseless as it seems. Well, the native bees like apis cerana japonica at least. European honey bees were introduced in Japan to increase productivity but with no defense against unknown predators like the giant hornet, whole colonies can be wiped out by just a few dozen giant hornets as seen.

Awesome bee-boying: The bee ball defense

Native bees, however, employ a clever strategy once they spot a hornet scout trying to call reinforcements via its pheromone trail: About a hundred will set a trap near the entrance to the hive, trying to lure the scouting hornet further inside where about 500 honey bees will surround it and suffocate it with their own densely packed bodies. In addition, they quickly vibrate their flight muscles, therefore increasing the temperature to 47 °C (117 °F), knowing well that the hornet cannot survive more than 46 °C (115 °F). The honey bees can barely stand it themselves and a few will die of overheating too but that’s a small sacrifice given what would happen if hornet reinforcements entered the hive…

Jeff Morales, producer of a film about the hornets for National Geographic, became quite attached during their, er, time together and has taken to defending them:

"Hornets get a bad rap for the most part, but they really are an integral part of a delicate ecosystem. … Social insects like the hornet are incredibly intriguing animals, and there are so many things we have yet to discover about their ways."
If you say so, Jeff. There is one consolation maybe: giant hornet workers will live only for a month.

Sources: 1, 2, 3

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Sources: 1, 2, 3

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