queens pip to each other, really. it is sort of like trash talking it is believed or a type of being a politician to tell the other bees "Hey, I'm the best, I am going to come out of this cell and beat the tar out of the other ones, because I'm the one you want." type of deal....least thats a theory, I do not speak fluent honey bee to know for sure.
So how long does it last? Only really as long as other queens are around, in their cells being developed/etc. 5 days isn't unheard of, and it can be from different sources also....if you hear a piping, and then suddenly a *ACK*, *COUGH*..."She got me...I'm coming home ester." then you know you probably won't hear it from the same sources the next day though, and someone was writing checks their butt couldn't cash.