In the insects’ world, the Japanese Giant Hornet (Vespa mandarinia japonica) is a real beast. It is one of the subspecies of the Asian Giant Hornet (Vespa mandarinia), which is the world’s largest hornet. As its name suggests, it is endemic to the Japanese islands, where it prefers rural areas where it can find trees to nest in.

Using its scissor-like teeth that can wreak havoc on its prey, a single Japanese giant hornet can kill up to forty European honeybees a minute. So, a few of them can decimate an entire colony containing 30,000 European honey bees. Compared to honeybees, it is a really giant: adults can be more than 4.5 centimeters (1.8 in) long, with a wingspan greater than 6 centimeters (2.4 in).

But, the Japanese honey bees have developed an amazing defense against these giants during their evolutionary process.

Japanese giant hornet has scissor-like teeth
Japanese giant hornet has scissor-like teeth that can wreak havoc on its prey.

Japanese giant hornet vs European honeybees

Once a Japanese giant hornet has located a hive of European honeybees it leaves pheromone markers around it that quickly attract nest-mates to converge on the hive. And the massacre begins.

European honeybees are generally more productive than the endemic Japanese honey bees. Because of that, In Japan, beekeepers often prefer European honeybees. But it is quite difficult to maintain a captive hive of European honeybees, as mentioned above.

European honeybees are completely defenseless against the Japanese Giant Hornet attacks. Watch what happens if a group of hornets attacks a European honeybee hive:

Once a Japanese giant hornet has located a hive of European honeybees it leaves pheromone markers around it that quickly attract nest-mates to converge on the hive. Then the horrible massacre begins. In the video above, only about 30 Japanese giant hornets kill more than 30,000 European honeybees.

Japanese giant hornet vs Japanese honeybees – a different story

However, the Japanese honeybee (Apis cerana japonica) has an amazing defense against these attacks. When a hornet approaches the hive to release pheromones, the bee workers will retreat back to the hive, leaving an opening to allow the hornet scout to enter.

At a given point, the bees emerge from their hiding places in an angry cloud formation containing some 500 individuals. They form a tight ball around the hornet that acts like a convection oven when the bees vibrate their wings to direct air over their bodies, warmed by their muscular exertion, into the inside of the ball.

The interior temperature of the ball rises to 47 °C (117 °F). The hornet can survive maximum temperatures of 44-46 °C (111-115 °F), but the bees can survive up to 48-50 °C (118-122 °F), so the hornet is killed and the bees survive. It was found that the hornet can survive temperatures of up to 47°C, and temperature alone is not sufficient in killing the hornet via bee ball.

The combined carbon dioxide concentrations increasing inside the bee ball coupled with the temperature increase causes the hornet to expire. The ability to withstand heat for the hornet rapidly decreases as carbon dioxide concentrations increase.

Japanese Honeybee thermal defence against Japanese giant hornet
Japanese Honeybee has a thermal defense against Japanese giant hornet. They form a tight ball around the hornet to increase carbon dioxide concentrations and the temperature around the beast. Some of them get killed by the hornet while building the ball, but their sacrifice saves the colony.

The amazing three-minute video below shows how the Japanese honeybees can kill a Japanese Giant Hornet forming a ball.

Japanese honeybees raise their body temperature to cook an invading Japanese giant hornet.
A National Geographic documentary named “Hornets from hell”. 
This clip shows the Japanese giant hornets wiping out a honeybee hive. The latter part of the clip shows the bees’ payback.

Sources

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