These buildings are the primary way to spawn new green Darwinians, and are the only way to do so in the first 8 missions, not including the prologue. Incubators also need Engineer’s to deposit souls to run, thus it’s a good idea to develop strategies on soul collection when capturing a new Incubator, or starting a new level without one under control yet.
Incubator’s are the key to rebuilding the Darwinian population within the game. These structures captured through the reprogramming of the attached Control Tower, allow Engineers to hover over with a load of spirits in tow, and drop them off inside the Incubator. After putting the souls inside the Incubator, they will respawned over time into green Darwinians.
The rate of which the souls are turned back into friendly physical bodies is directly proportional to how many souls are currently within the Incubator pending respawn. Piling a heavy load of souls into an Incubator in Darwinia will literally cause it to spit a stream of little green pixel men into the air as though it were literally a fountain of rebirth.
In later levels the Biosphere and Temple, the Incubators will be replaced with the Spawners that automatically create a steady stream of Darwinians with the souls provided to them through the Receiver and Pattern Buffer facilities. Although many of the Incubators start off under virus control, they cannot be utilized by the enemy unlike the Spawners. In addition, it is typically a good idea to capture these as soon as possible on the maps that have them, to prevent wasting souls to the sky, as they float way over time if not collected and incubated.