The world’s largest hornet is the Asian giant hornet (Vespa mandarinia). An individual specimen can measure up to 5 cm (2 inches) long and has a wingspan of 7.6 cm (3 inches). Giant hornets have blunt wide heads which look different from those of other wasps, hornets, and bees and they are colored yellow orange and brown.
The Asian giant hornet ranges from Siberia down across the Chinese coast into Indochina and lives as far west as India, however the hornet is most common in the rural parts of Japan where it is known as the giant sparrow bee. The sting of the Asian giant hornet is as oversized as the great insect is. Within the hornet’s venom is an enzyme, mastoparan, which is capable of dissolving human tissue. Masato Ono, an entomologist unlucky enough to be stung by the creature described the sensation a “a hot nail through my leg.” Although the sting of a normal honey bee can kill a person who is allergic to bees, the sting of an Asian giant hornet can kill a person who has no allergies–and about 70 unfortunate souls are killed by the hornets every year.
Armed with their size and their fearsome sting, Asian giant hornets are hunters of other large predatory insects like mantises and smaller (i.e. all other) hornets. The giant hornets do not digest their prey but masticate it into a sticky paste to feed to their own offspring. A particular favorite prey is honey bee larvae, and since European honey bees have no defense against the giant wasps, all efforts by Japanese beekeepers to introduce European bees have met with failure. Japanese honey bees however have evolved a mechanism (strategy?) to cope with hornet incursion. When a hive of Japanese honey bees detects the pheromones emitted by hunting hornets, a crowd of several hundred bees will form a gauntlet (carefully leaving a space for the hornet to enter). Once the hornet walks into the trap the bees rush on top of it and grasp it firmly. They then begin to vibrate their flight muscles which raises the temperature and produces carbon dioxide. Since giant hornets cannot survive the CO2 levels or high temperatures that honey bees can, the hornets put up a titanic struggle to overcome the mass of bees, killing many in the process. However honey bees have a fanaticism which would do credit to the most ardent practitioner of Bushido, and they usually kill the invaders.