The Yanme'e Minor is the lowest Drone rank. A minor drone flies slower than Drone Majors. All the Drones you encounter in Halo 2 and Halo 3 are Minor Drones; there are no Drone Majors. They are often seen commanded by Drone Leaders in Halo 3: ODST.
Logically, Drone Minors are the lowest of the Drone ranks. They are commanded by Drone Majors, Jackals, and Grunt Majors. They seem equal, if not even inferior in rank, to the Grunt Minors, placing them at the very bottom of the Covenant hierarchy. However, they also may be higher in rank than the Grunts due to the fact that they appear alongside Brutes and Elites in Halo 2 and Halo 3. Like the Grunt Minors, however, they seem to be extremely low in rank due to the fact that even a Jackal Minor can command them.
Usually found equipped with Plasma Pistols, Needlers, and rarely Plasma Rifles, Drone Minors are very low in rank, but like the Grunts, when in large groups are quite a deadly threat. They also are fairly good shots, especially on Heroic and Legendary. Most of the time Drone Minors will be in large swarms against the player, and can be quite dangerous.
Drone Minors, while powerful in swarms, are weak individually, like the Unggoy. They can be taken down fairly easily, and will often make tactical errors such as flying into an enemy's line of sight, or getting in the path of another Drone's shot. They also need to land occasionally, which makes them extremely vulnerable.
A Drone Minor can be taken down easily with an SMG, Battle Rifle, Plasma Rifle, or Assault Rifle. They are also weak against the Needler. Firing 7 Needles will cause an explosion large enough to take out an entire group of Drones. However, as the Halo 2 Official Strategy Guide points out, they can be deadly in conjunction with Grunts, Jackals, Elites, and Brutes.
In Halo 2, Drone Minors all have green exoskeletons, and in Halo 3 and Halo: Reach, they always have yellow exoskeletons. In Halo 3: ODST, however, they have green, blue, and silver exoskeletons.