Hey, if you happen to be a hornet reading this, be aware that honey bees know who you are and want you to go away!
A recent experiment done by a team of international researchers found that when a hornet came close to a hive of honey bees, they would react with a shaking motion of their abdomens that would essentially tell the hornet to buzz off. The hornet would comply and would instead try to attack a bee while in mid flight instead of with the group.
This experiment was carried out by attaching a live wasp to a probe and then brought it close to the bee hive entrance. The closer it was brought, the more intensely the bees reacted.
"To confirm that the bees were specifically "talking to" the hornets with this signal, the team carried out the same tethering experiment with a harmless butterfly species (Papilio xuthus). This insect is slightly larger than the hornet and has very similar yellow and black markings. Despite the similarity, the bees did not respond to the butterflies, no matter how close they came to the hive."
Pretty cool stuff. Check out the source article here.