- “Murder hornets,” also known as Asian giant hornets, are colonizing the United States and were first sighted in Washington state in December.
- While their stings can kill humans, honeybees are their primary targets.
- Japanese honeybees have developed a technique called a “hot defensive bee ball” to roast the hornets alive in a ball of vibrating bees.
Just over four months into the year, 2020 is already presenting some perilous obstacles. The latest iteration in a series of unfortunate events is the arrival of the “murder hornet,” also known as the Asian giant hornet, in Washington State, where it has never been previously spotted.
News of the hornet spread quickly across social media by virtue of the ridiculous timing of the news, but in actuality, the insects aren’t that deadly to humans — in Japan, the insects typically kill between 30 and 50 people per year; during one particularly bad hornet season in the Shaanxi province in China in 2013, they killed 42. That being said, humans are hardly the hornet’s primary target. That honor belongs to honeybees, which are already on the decline in the United States.
Asian giant hornets are best known for their ability to decimate honeybee hives, decapitating bee after bee during what the Washington State Department of Agriculture called a “slaughter phase” in a blog post, destroying one hive within a matter of hours.
In Asia, however, the bees have learned to fight back. Researchers have observed Japanese honeybees specifically (as opposed to their European counterparts) forming “hot defensive bee balls” in order to collaboratively cook hornets at a temperature that the bees can withstand but the hornets cannot. By surrounding the hornets and vibrating their flight muscles, the honeybees produce heat up to 47 degrees Celsius (116 degrees Fahrenheit).
A National Geographic video shows the process in action, explaining how it serves to protect the hive as a whole. A solitary “murder hornet” scout approaches a honeybee hive as a means of scouting out the hive and marking it with a pheromone that will allow fellow hornets to find it. That solitary approach will prove to be its downfall.
The video shows the hornet being swarmed by hundreds of bees all at once, with thermal photography revealing the temperature increase as the honeybees raise the temperature within the bee ball to a precise temperature and roasting the hornet alive.
Regrettably, European honeybees, which are the most common pollinators in the United States, haven’t developed the same bee ball technique, allowing hornets to decimate their hives given that the bees’ stingers cannot pierce the hornets, scientists say.