Wow.

indigenous bees have methods to deal with these wasps, evolved over eons no doubt. european bees had never had to deal with wasps like these and panic when they appear. there is a video somewhere of a single scout wasp being engulfed by a number of indigenous bees, which suffocate and overheat it to death. were it possible to cross the european bees with the japanese variety, the hybrid may stand a better chance. either that, or the european import will need to evolve a protection similar to their cousins.

Headline - The Daily Bee: "A date which will live in infamy!"

Interesting. I wonder if how you could train European bees to react this way?

Not sure about the temperature thing - I'd assumed the hornet was overcome by being on the inside of the bee 'blanket'. And the bees have a higher surface area to volume ratio so could dissipate heat more effectively.

On training, speculating, European bees might have a similar response to another predator. If these sorts of responses are driven by pheromone or other signalling, perhaps hives could be trained by introducing hornets alongside the appropriate signal. It works for higher species (eg. For naïve bird species, introducing cats alongside recorded alert song from the same species). Don't know if this can work for insects though. They might surprise us.