For the species of seed harvesting ants I am familiar with in California - Pheidole and Pogonomyrmex - seeds are milled in the jaws of workers and the milled fragments are fed to the larvae. I wouldn't be surprised to see that others of your correspondents describe other ways that seeds are used.
If you are interested in following this literature, you might look for papers about Veromessor (Messor) pergandei. It's workers are polymorphic and they are very well studied regarding foraging behavior and the size of workers that are recruited to gather seeds of various sizes. There have been many papers published about this subject.