Cyclists hospitalised after hornet attack in France What are hornets? Hornets are the largest of the wasp family native to Europe. Like bees, hornets live in large colonies with a single queen and thousands of workers and build their nests from tree fibres. While hornets usually prefer to avoid contact with humans, they will sting as a defence mechanism in response to having their nest disturbed, and can be aggressive near their food source too. Hornets hunt insects like beetles, moths, dragonflies and wasps. They will also eat rotting fruit they might find on the ground.