Figure 2. Two nest architectures found in Mycocepurus nests. (A) Tree-like architecture of a M. goeldii nest (CR 17). Eight of the eleven total fungus chambers are depicted in the cross section; the fungus gardens are not shown. (B) Necklace architecture of a M smithii nest (CR 7). The nest consisted of four chambers: the three lowermost ones were filled with a fungus garden, while the deepest chamber contained only a few mycelium strands, characteristic for recently built chambers. The uppermost chamber was abandoned, filled with organic matter from the decaying fungus garden and first rootlets started to grow into the cavity. Because workers fill exiting tunnels of chambers with exhausted and/or parasitized fungus gardens with soil, the chamber was no longer connected to the main tunnel. Both cross sections are drawn to the same scale. Drawings by S. C. Cappellari.