Worker bees will cuddle an old queen bee to death!

When a new queen is available, the workers will kill the reigning queen by "balling" her, colloquially known as the "cuddle death"; clustering tightly around her until she dies from overheating. This overheating method is also used to kill large predatory wasps that enter the hive in search of food and may be used against a foreign queen attempting to take over an existing colony. Balling is often a problem for beekeepers attempting to introduce a replacement queen.

Supersedure,  the process by which an old queen bee is replaced by a new queen. Supersedure may be initiated due to old age of a queen or a diseased or failing queen. As the queen ages her pheromone output diminishes.

Supersedure may be forced by a beekeeper. For example, by clipping off one of the middle or posterior legs from the queen, she will be unable to properly place her eggs at the bottom of the brood cell. The workers will detect this and will then rear replacement queens.

When a new queen is available, the workers will kill the reigning queen by “balling” her, colloquially known as “cuddle death”: clustering tightly around her until she dies from overheating. This method is also used by Japanese honeybees to kill large predatory wasps that enter the hive and may be used against a foreign queen attempting to take over an existing colony. Balling is often a problem for beekeepers attempting to introduce a replacement queen.

If a queen suddenly dies, the workers will flood several cells, where a larva has just emerged, with royal jelly. The young larva floats on the royal jelly. The worker bees then build a larger queen cell from the normal sized worker cell and it protrudes vertically from the face of the brood comb. Emergency queens are usually smaller and less prolific, and therefore not preferred by beekeepers.

Source: wikipedia