Vespa mandarinia raids honey bee colonies, and a successful raid destroys the hive. The native Japanese honey bee has a counter. When a scouting hornet arrives, workers do not sting; they mob it, forming a tight ball of several hundred bees around the intruder and shivering their thoracic muscles.
The interior of the ball heats to roughly 46 degrees Celsius while carbon dioxide concentration rises. Bees tolerate that combination for the twenty minutes or so it takes; the hornet does not, and dies. The margin is narrow, which is why the behaviour depends on both heat and elevated carbon dioxide rather than temperature alone.
The defence is learned nowhere and possessed by no import. European honey bees kept in Asia lack it and are destroyed by raids, which is the practical reason the hornet is treated as a threat to beekeeping. In North America a population found in Washington State and British Columbia from 2019 was subject to an eradication programme, and the United States Department of Agriculture declared it eradicated in December 2024.