Queen Mothers resembled both Queens and Empresses in a variety of ways. They are different in a few obvious ways, such as their crests which are shorter than a Queen or Empress' Crest.
Biology and MannerismsEdit
The Mother's nests consist of six orbs arranged around a central orb in which they reside. These orbs contain the prized Royal Jelly which possibly molts a Warrior into a new Queen or Queen Mother when one is absent, as seen with Specimen 6. Queen Mothers have acute telepathic and empathic abilities which means they can contact their hive over vast distances. The Queen Mothers are similar to Queens because of their ability to lay Eggs. They have been observed waging war on each other, indicating typical animal rivalry.
The Queen Mother has outstanding/horrifying capabilities that other Xenomorphs lack, ones that haven't been witnessed so far by humans. She has extraordinarily powerful telepathic capabilities that allow her to command the whole of the Xenomorph species throughout the universe, and at the same time she can telepathically control creatures that are not Xenomorphs. The Queen Mother, during the Earth Wars, took control of a lot of the human population, turning them into something similar to an Infectoid. She was even able to control humans that were in such bad physical state that they would be considered dead.
The Queen Mother has also been shown to be able to communicate through dreams/nightmares with other creatures, and has some form of empathic capability. With this, the Queen Mother has the potential to drive people mad.
It is not known if she is the cause, or if the rest of the Xenomorphs have minor empathic capabilities, but before a Xenomorph Invasion there have been more than a handful of cases where people had nightmares about Xenomorphs before even knowing what they are, or that they even existed.
Another strange ability the Queen Mother has is the ability to merge with the Hive Resin. Unlike the Warriors and other Xenomorphs that hide on or within indentations of the Hive, the Queen Mother can use it like it is a portal or interact with it in such a way that it doesn't act as a physical obstruction to her. 
InformationEditThe first Queen Mother was kidnapped by Ellen Ripley in the novel Aliens: The Female War which led to complete and utter chaos on the Hiveworld. While a Warrior was morphing into a new Queen Mother to take the original's place, several deviant Drones designated as "red Drones" by the humans were born and rebelled against the primary Hive.
Soon after countering a Hive consisting of the red Drones led by the Red Queen Mother in the comic Aliens: Genocide, massive warfare begun between the two subspecies over the genetic abnormalities. A fleet of Colonial Marines were sent to the Hiveworld to retrieve the Queen mother's prized Royal Jelly in order to synthesize a highly addictive drug called Xeno-Zip. The crew decided to nuke the Red Queen Mother's Hive to distract the Drones of the original nest while the Royal Jelly was being extracted. The remaining Queen Mother was shot after killing a scientist during the extraction.