yes

They will help break some of the compost down into finer soil. And when they've finished reproducing this year, the colony will disappear. The queens will go off to found another colony for next spring.

According to the "recycle now" website, ants in the compost heap are a sign that it is too dry. You could add a few buckets of water to it, or add more "greens" eg grass clippings, vegetable & fruit peelings.
http://www.recyclenow.com/home_composting/get_advice/making_compost_faqs/my_compost_bin_is.html

Come on Beattie! How would you like someone to take off the roof of your house, throw in some buckets of water, and then dump a load of greens in the top storey?
However, you're right the heap must be too dry as ant nests are always in very dry ground.

The Recycle Now website also advises stirring the nest / compost heap often to make the little critters decamp - but I didn't publicise that as even I thought that that was cruel.

Whoops!