In the Neotropical rainforest of Barro Colorado Island, Panama, social organization and behavior were observed in 2 primitive attine ant species, Myrmicocrypta ednaella and Cyphomyrmex rimosus. Both species took nutrients from mycelia on fungus (i.e, mycophagy), and from plant nectar and sap which they collected outside the nest (i.e. phytophagy). They also obtained alimentary liquid by soliciting nestmates (i.e. stomodeal trophallaxis). Queens and larvae were wholly mycophagous, while older workers were much dependent on nectar, sap and alimentary liquid and younger workers were mostly mycophagous but only partly phytophagous. M. ednaella used wood chips as substrate for the fungus garden. Its fungus-growing behavior was similar to those hitherto observed in other primitive attine species. In contrast, the behavior of C. rimosus was unique in its utilization of crop liquid as a substrate. In the rainforest, C. rimosus workers frequently forage outside the nests to collect nectar and sap, most of which is probably regurgitated for fungus cultivation.
