In Ender's Game, it's clear that the final battle was the first one staged around a planet:

"For this to be a fair test of your ability, not just to do what you have practiced many times, but also to meet challenges you have never seen before, today's battle introduces a new element. It is staged around a planet." (Mazer Rackham, chapter 14)

But at the same time, it's later made clear that the buggers had colonized other planets:

"As soon as we get the reports back on the bugger colony worlds. I mean, there they are, already fertile, with housing and industry in place, and all the buggers dead." (Graff, chapter 15)

And that there wasn't just one or two queens, but rather several:

"When he came to the tale of the great mother, the queen of all, who first learned to keep and teach the new queen instead of killing her or driving her away ... This was a new thing in the world, two queens that loved and helped each other instead of battling, and together they were stronger than any other hive. They prospered; they had more daughters who joined them in peace; it was the beginning of wisdom." (Chapter 15)

So how did the Third Invasion work? How were there no queens on any other planets? Were the buggers actually so stupid that all of their queens were on one planet (or on ships), even though inter-stellar communication seemed to work fine? And did the IF assume there was just one queen, or knew exactly where they all were, or something?

I've read a couple of the Ender sequels, and don't remember this being addressed, but it's been a while.

(Sorry for the sort of vague question title -- still trying not to spoil the story for those who haven't read it.)