Buzz off!
WASHINGTON STATE, US
In October, the US’s first confirmed nest of Asian giant hornets (Vespa mandarinia) was destroyed by scientists in Washington state. The invasive insects are also known as ‘murder hornets’ as they are voracious predators of honeybees, which are important pollinators of crops.
The team attached tiny tracker devices to some worker hornets, which led them back to the nest in a tree cavity. The vacuum device seen here was used to extract the insects, before carbon dioxide was pumped into the tree to anaesthetise any stragglers. The scientists had to wear protective suits, as the hornets can sting multiple times and are able to spray venom.
While US bees cannot defend themselves against the hornets, Japanese honeybees, having evolved alongside the predators, have a trick to ward off attacks: when a ‘scout hornet’ first enters their hive, the bees form a tight ball around it, increasing carbon dioxide levels and raising the temperature to kill the intruder.