Procreation is the drone’s primary purpose in life. Despite their high maintenance (they must be fed and cared for by the worker bees), drones are tolerated and allowed to remain in the hive because they may be needed to mate with a new virgin queen (when the old queen dies or needs to be superseded).
The few drones that do get a chance to mate are in for a sobering surprise. They die after mating! That’s because their sex organ is barbed (like the worker bee’s stinger). An organ inside the queen called the “spermatheca” is the receptacle for the sperm. The queen will mate with several drones during her nuptial flight. After mating with the queen, the drone’s most personal apparatus and a significant part of its internal anatomy is torn away, and it falls to its death.
Excerpts from Beekeeping For Dummies: Understanding the Role of the Drone Bee in a Hive By: Howland Blackiston