Bevendre

Headcanon: Whenever a drone dies, it's ghost echoes in the hive mind. Eventually when enough of these "ghosts" build up, the queen goes mad from them. This is what drove Chysalis to attack Canterlot and is also why no hive has lasted more than a century. The queens cannot die of old age but they have all eventually succumbed to the whispers of the fallen that they led.