Portrait of a social parasite, Aphaenogaster tennesseensis. Urbana, Illinois, USA
Dorymyrmex reginicula (at left), a socially parasitic species, is harassed by a worker of its host Dorymyrmex elegans. Workers of the two species coexist in a single nest for a period after the parasite queen has assumed reproduction and before the last remaining host workers die off. The transition period is not entirely smooth, as evidenced by this aggressive interaction. Archbold Biological Station, Florida, USA