Ecology and evolution of truffle fungi : the diversity of fungi associated with northern flying squirrels

Abstract

"This thesis explores the ecology of truffle fungi, a diverse assemblage of symbiotic mycorrhizal fungi that extend microscopic hyphae throughout forest floors, forming networks of foraging mycelium capable of transporting water, vitamins, minerals, and other nutrients to the roots of plants. Plant sugars are used for energy and as raw material for the creation of complex reproductive structures and vast water and nutrient gathering infrastructures essential to the survival of most plants. Truffle fungi are defined here by their ability to form mycorrhiza and produce truffles: hypogeous sporocarps that are excavated and consumed by animals ranging from squirrels to humans, resulting in the long-distance transport of spores. In Chapter 1, I compile and synthesize published information on the evolution and ecology of truffle fungi. In Chapter 2, I describe molecular techniques used to extract, amplify, and characterize fungal DNA from the scat of an endemic island population of northern flying squirrels, Glaucomys sabrinus griseifrons, which specialize in the consumption of truffles. Statistical analysis of RFLP data from clones of fungal DNA indicates much higher levels of fungal diversity in G. s. griseifrons scat than expected. I argue that the estimated numbers of fungi associated with G. s. griseifrons represent a baseline of diversity for fungi associated with mainland populations of Glaucomys sabrinus"--Leaf iii