Japanese Honey Bee

Apis cerana japonica

Japanese Honey Bee (Apis cerana japonica): The Bee That Cooks Giant Hornets

The Japanese Honey Bee (Apis cerana japonica) is the eastern honey bee of Japan. It is smaller and darker than the western honey bee, and it defends its nest from northern giant hornets by engulfing a scout in a ball of bees and heating it to death.

Habitat
Forests, satoyama farmland and urban parks below ~1,000 m
Size
Workers 10–13 mm, 60–90 mg
Diet
Nectar and pollen, often from tree flowers
Range
Japan: Shimokita Peninsula to the Amami Islands
Colony
Several thousand to about 20,000 bees
Defence
Heat ball of 500+ bees at about 46–47 °C

Habitat & range

Japanese honey bees live on Honshu and the surrounding islands, from the Shimokita Peninsula in Aomori Prefecture in the north to the Amami Islands of Kagoshima Prefecture in the south, mostly below about 1,000 m. They use forests, satoyama farmland mosaics of woods and rice fields, and urban parks. Wild colonies nest in sheltered cavities such as hollow trees, and beekeepers also keep them in simple wooden log or box hives. A colony holds from several thousand to about 20,000 bees, roughly a third to half the size of a typical western honey bee colony.

Diet & foraging

Like all honey bees, workers collect nectar and pollen and turn the nectar into honey. Japanese honey bees favour trees with plain flowers and visit mountain species such as the Amur cork tree (Phellodendron amurense) and Meliosma myriantha. That taste for woodland flowers, together with their defences against hornets, helps them survive deep in the mountains where western honey bees struggle on their own. Their honey is a niche product: about 30 tonnes a year are harvested in Japan, compared with about 2,800 tonnes from western honey bees. The oriental orchid Cymbidium floribundum releases a chemical mix that Japanese honey bees recognise, which draws them to its flowers.

Behavior & adaptations

The Japanese honey bee shares its range with the northern giant hornet (Vespa mandarinia), a predator that can wipe out a honey bee colony. A hunting hornet marks a hive with a pheromone so nestmates can join a mass attack. Japanese honey bees detect that mark and send more defenders to the entrance. When a hornet is caught, more than 500 workers can engulf it in a tight ball and shiver their flight muscles. Thermal imaging in Ono and colleagues' 1995 Nature study measured about 47 °C inside the ball, which kills the hornet but not the bees. The bees can survive about 50 °C, a few degrees more than the hornet can. After a giant hornet scouts the hive, workers also perform an emergency dance and smear chewed plant material around the entrance, a response that two smaller hornet species did not trigger in experiments.

Conservation

Japanese honey bees survived the arrival of western honey bees in 1877, but felling of the woods and old trees they nest and feed in since the 1960s, along with increasing use of neonicotinoid pesticides, have put pressure on them. The parasitic mite Varroa destructor, a serious pest of western honey bees worldwide, originally lived on the eastern honey bee, and the Japan/Thailand mite strain is a natural parasite of Apis cerana in Japan. Today about 5,000 beekeepers in Japan keep the bee, only 50–100 of them commercially.

Taxonomy & relatives

The Japanese honey bee is a subspecies of the eastern, or Asian, honey bee Apis cerana, in the bee family Apidae and order Hymenoptera, alongside ants, wasps and hornets. Its workers are about 10–13 mm long and weigh 60–90 mg, against 12–14 mm and 80–150 mg for the western honey bee (Apis mellifera). It is darker and less hairy, with even pale bands across a dark abdomen, and darker, shorter wings. Its closest relative in Wilder is the Western Honey Bee, and its great enemy is the Northern Giant Hornet.

Fun facts about Japanese Honey Bee

  • A heat ball can contain more than 500 bees wrapped around a single giant hornet.
  • The bees pick up the hornet's own marking pheromone and send extra guards to the entrance.
  • After a giant hornet scouts the hive, workers dance and smear chewed plants around the entrance. Two smaller hornet species tested didn't trigger it.
  • A worker develops from egg to adult in about 19 days, about two days faster than a western honey bee.
  • The Varroa mite that devastates western honey bees worldwide originally lived on eastern honey bees like this one.

Japanese Honey Bee vs Northern Giant Hornet

The Japanese Honey Bee wins as a colony: the heat ball kills the scout before it can bring the rest of its nest.

This matchup really happens every autumn in Japan. A northern giant hornet scout lands at a Japanese honey bee nest, ready to mark it for a mass attack. One bee alone has no chance against a hornet many times its size. The colony doesn't fight alone. Hundreds of workers pile onto the scout and shiver their flight muscles until the ball reaches about 46–47 °C. Heat and the carbon dioxide trapped inside kill the hornet within minutes, and the bees, which can survive a few degrees more, walk away. If the scout gets home and recruits its nestmates, the bees are in real trouble. Killing that first hornet is what saves the colony.

Read more about Northern Giant Hornet.

Common questions about Japanese Honey Bee

Is it the heat or carbon dioxide that kills the hornet in a bee ball?

Both. In lab tests, giant hornets survived 10 minutes at 47 °C in normal air. Inside a real bee ball, carbon dioxide rises to about 3.6%, and at that level the hornet dies at about 45–46 °C. The bees can survive about 50–51 °C under the same conditions (Sugahara & Sakamoto 2009).

Why can't western honey bees defend against giant hornets?

Western honey bees evolved without giant hornets, and they have no reliable answer to a mass attack. A small group of hornets can kill nearly all the adults in a colony of 30,000–50,000 workers within a few hours (WSU/WSDA). Japanese honey bees evolved alongside the hornet and detect its marking pheromone (Ono et al. 1995).

Is the Japanese honey bee the same as the Asian honey bee?

It is a subspecies of it. The Asian or eastern honey bee is Apis cerana, found across much of Asia, and the Japanese honey bee is its Japanese subspecies, Apis cerana japonica, known in Japan as Nihon mitsubachi (Slow Food Ark of Taste).

How can you tell a Japanese honey bee from a western honey bee?

Japanese honey bee workers are smaller (10–13 mm vs 12–14 mm) and darker, with less hair and more even pale bands across the abdomen. Their wings are also darker (Nippon Foundation Library; Biosecurity Queensland). Compare the Western Honey Bee card.

Do Japanese honey bees get Varroa mites?

Yes. The eastern honey bee is the original host of Varroa destructor, the mite that became a serious pest after switching to western honey bees. One of the two strains that spread to western honey bees worldwide, the Japan/Thailand type, is a natural parasite of Apis cerana in Japan (Anderson & Trueman 2000).

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