Mystrium voeltzkowi has an unusual caste system. These unusual ants are dimorphic, with a small red caste that appears to work mostly in the brood nest and a larger, dark caste that performs most of the foraging and guarding of the nest. Interestingly, the ants that perform as reproductive queens are drawn from the smaller caste. Madagascar
Myrmecocystus mimicus alate female, worker, and larva. Carrizo Plain Nat'l Monument, California, USA
