Chitauri Motherships
The Chitauri Motherships are Artifially Intelligent Starships, which serve as both the homes and the hive-queens of the Chitauri.
It is unknown who first developed the Motherships: most historians and anthropologists agree that the Chitauri were not originally a hive species, meaning the Motherships were not developed the replace biological queens. However, whether they were developed by the Chitauri themselves (assuming that prior to the Motherships, they possessed sufficient individual intelligence to develop technology, something which is no longer the case), or imposed on the species by an external force is unknown. Some Kree exo-biologists have theorised that the Motherships might originally have been developed as a defence against Brood Queen mind-control.