In all the films that have displayed a Queen, the Queen's have had a smaller secondary set of arms extending from the center of her chest area.
There have been a lot of theories as to what purpose they serve, from eating to mating etc...
I think for several reasons that these theories are a little too complex, although they do have some merit.
The theory that I like the most is the most simple one.
See the Dark Horse comics AVP deadliest of the species for this one.
Egg carrying.
There is only one situation where she would ever have to do this.
Leaving the nest in an emergency.
In A2 there were no good eggs left to grab, as Ripley had torched them, and that may be why the Queen did not do this there. It does not mean she would not have if there were still some good eggs close by. Same thing with the AVP Queen. There were no convenient eggs for her to grab either.
In other situation of emergency, with eggs available, the Queen could use these smaller secondary arms to grab and egg or two before she leaves her nest. This way she would have eggs to make more aliens to help gather hosts in a new hive before she is even done regenerating her egg sack.
With the secondary arms holding the egg(s) she would still have her bigger primary arms freed up to do "whatever it takes" to survive.
This way she could functionally move with all the advantages of an adult alien, other than her massive size, get out of the hive, and still be able to take an egg or two with her.
