Ants that culture fungi for food belong to the tribe Attini (Hymenoptera, Formicidae); a monophyletic group of more than 210 species of fungus-growing ants, distributed in 12 genera (Chapela et al., 1994; Wetterer et al., 1998; Brandão and Mayhé-Nunes, 2001; Mueller et al ., 2001). Fungus-growing ants are exclusively Neotropical, and the most specious group of the tribe includes the eight “lower” attine genera Apterostigma, Cyphomyrmex, Mycetosoritis, Mycetophylax, Mycetarotes, Mycocepurus, Mycetagroicus, and Myrmicocrypta (Schultz and Meier, 1995). Most “lower” attines have relatively small colonies of a few dozen to a few thousand individuals, have few relatively small fungus gardens, and are characterized by their use of plant detritus or insect feces as substrate for fungiculture (Weber, 1966, 1972; Hölldobler and Wilson, 1990; Mueller and Wcislo, 1998). The remaining four genera (Sericomyrmex, Trachymyrmex, Acromyrmex, and Atta) are commonly referred to as the “higher” attines, with the latter two being referred to as leafcutting ants (Figure 4.1A), due to their use of fresh plant material for culturing their fungi.