Bee

Bees were a species of non-sentient insect native to Earth. They were domesticated by humans for the production of honey, and even an average human like Donna Noble knew that they were experiencing a profound global downturn in their population during the early 21st century. (TV: Delta and the Bannermen, Partners in Crime)

Honey
Many bees lived in colonies, collecting pollen to be created into honey. Bees were domesticated by humans for their honey. They were a hive society with a fertile queen, male drones, and infertile female workers. A larva developed into a queen if fed royal jelly.

In 1959, Goronwy kept bees. He gave the Seventh Doctor a jar of his rare 1928 hibiscus blossom. The Bannermen invaded his honey store and were covered in the substance, this caused the bees to attack them. (TV: Delta and the Bannermen)

Disappearance
For an unknown amount of time, Earth's bees lived alongside—and humans never knew that they were different from—visiting, sapient Migrant Bees of the planet Melissa Majoria. When the Migrant Bees suddenly left Earth in the early 21st century, scientists were flummoxed as to the cause of the sudden drop in the bee population, unaware that they were studying the wrong type of bee for an answer. (TV: Partners in Crime, Planet of the Ood, The Unicorn and the Wasp, Turn Left, The Stolen Earth) Eventually

Eventually the Earth's native bee population dwindled to near-extinction levels. However, bees were being reintroduced to the UK in June 2027, and, according to Ace, the bee problem would be solved by 2040. (AUDIO: A Death in the Family)

Miscellany
The Fourth Doctor professed to be rather fond of bees. (TV: The Robots of Death)

Romana compared K9's greeting to a computer to the identification dance used by bees. When asked what bees were, the Fourth Doctor replied "Insects! With stings in their tails". (TV: The Armageddon Factor)