Harvester ants such as Messor reaping the seeds of grasses and grains and store them in their underground nests.

The size difference of these ants between workers is extreme because of the specialization. To break the grain, their mandibles and their heads have become disproportionate.

here is also a caste of "milling " that separates the seeds from their husks, mince, mix it with saliva and form a sticky, sugary food.