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The ant genus Apterostigma is in the Attini, the tribe of fungus-growing ants, but looks little like other attines. They are shaped more like generalized myrmicines such as Aphaenogaster or Pheidole. A few species have short teeth or tubercles on the propodeum but otherwise they never have spines. They are all covered with a distinctive wooly pilosity. Species vary in details of size and shape, but in general they have a uniform habitus.
Apterostigma is probably the sister taxon to all other attines, and the fungus they cultivate is also a distinct lineage very different from fungi used by other attines (Chapela et al. 1994, Hinkle et al. 1994).
Apterostigma are common elements of Neotropical ant faunas throughout the Neotropics. The colonies are always small and occur under dead wood on the ground, under stones, between leaves in the leaf litter, in cavities in dead wood, under epiphyte mats, and between leaf bases of bromeliads. One species in Costa Rica, A. collare, has the striking habit of building exposed fungus nests on the undersurfaces of leaves, under branches, and on tree trunks in the low arboreal zone. The nests are several centimeters long and covered with a diaphanous white envelope composed of fungul hyphae, which makes them very conspicuous.
Chapela, I. H., S. A. Rehner, T. R. Schultz, and U. G. Mueller. 1994. Evolutionary history of the symbiosis between fungus-growing ants and their fungi. Science 266:1691-1694.
Hinkle, G., J. K. Wetterer, T. R. Schultz, and M. L. Sogin. 1994. Phylogeny of the attine ant fungi based on analysis of small subunit ribosomal RNA gene sequences. Science 266:1695-1697.
Lattke, J. E. 1997. Revisi—n del gˇnero Apterostigma Mayr (Hymenoptera: Formicidae). Arq. Zool. (S‹o Paulo) 34:121-221.
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. email@example.com
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