The Queen Spawn is the reproductive unit of a Spawn hive. Really the Queen has no authority over the other Spawn, as she is not a Command unit her only real motive is to reproduce, she does however require constant maintenance and the colony will defend her with their lives because if she dies, they all die.
While no Queens are encountered in gameplay, they are still there. The Queen is generally laying on her back with a large Birth Sack which constantly produces fresh Seed Spawn and Mega Spawn. With a Queen around, a Spawn infestation can increase their spreading speed ten fold. She is generally 40 feet long and 12 feet high and most of the time is intermeshed with the Hive Biomass itself, a part of the hive, a living tool. Older Queens are called Spawn Cores and are much more powerful than a Queen and can live as long as 12,000 years.