The practice of cultivating fungi as a primary food source has evolved multiple times: in leaf-cutting ants, in termites, and in several groups of beetles. In many cases, these fungus-farming insects have a major influence on the structure and function of their native terrestrial ecosystems.
Fungus farming has now been found in a very different organism--one that lives in a semi-aquatic realm. Silliman and Newell surveyed the feeding habits of the marine snail Littoraria irrorata in salt marshes on the Atlantic cost of North America. The snails graze on saltmarsh cordgrass, Spartina alterniflora, opening wounds that are colonized by ascomycete fungi on which the snails feed. The facilitation of fungus colonization by the snails significantly depresses cordgrass growth, disproportionately beyond the physical damage inflicted by the snails. This phenomenon is widespread in salt marshes along the Atlantic coast, and the authors speculate that similar fungus-farming relationships may be as yet undiscovered in marine habitats. -- AMS
Proc. Natl. Acad. Sci. U.S.A. 100, 15643 (2003).
