Dispersal of fungal and slime mold spores by vertebrate and invertebrate vectors

Toyota Auditorium, Howard H. Baker Jr. Center for Public Policy

Numerous animals, including both vertebrates and invertebrates, serve as vectors for the spores of fungi and slime molds in terrestrial ecosystems. This is particularly important for dictyostelids (cellular slime molds), since the spores in this group of organisms are encased in a mucilaginous matrix that dries out, essentially eliminating the possibility of the spores being dispersed by wind. The latter is thought to be the primary method of dispersal for the spores of myxomycetes (plasmodial slime molds) and most fungi, but the consistent presence of spores in fecal material and on the body surface of animals ranging from insects to salamanders, birds and mammals suggests that many different invertebrates and invertebrates play an important but as yet understudied role in at least short-distance dispersal. Some species of birds travel considerable distances over relatively short time periods, especially during the course of annual migration and it seems likely that they would be able to serve as vectors for long-distance dispersal. Some evidence that this happens for dictyostelids already exists, and circumstantial evidence appears to indicate that birds were responsible for creating advance centers of infection for the chestnut blight fungus when the latter spread rapidly throughout the eastern United States in the early part of the last century. Truffles and other fungi are sought out by mammals yet the link between animal mycophagy and dispersal in North America is still largely unknown.