Nutritional Ecology of a Mycophagous Marsupial in Relation to Production of Hypogeous Fungi

Many forest—dwelling small mammals feed on the sporocarps of hypogeous fungi, but the nutritional value to small mammals of these sporocarps is thought to be low. The study investigated the value of hypogeous sporocarps to a mycophagous marsupial, the Tasmanian bettong, Bettongia gainmardi, by monitoring diet composition (via fecal analysis) and energetics in a free—ranging population in relation to variations in sporocarp production. The occurrence of fungus in the diet reflected sporocarp production. When production was high, the animals were almost exclusively mycophagous, while at lower levels of production they added dicot fruit and leaf to the diet. Females were slightly but consistently more mycophagous than males. Body condition in both sexes tended to increase with increased representation of fungus in the diet. Further, rates of energy turnover in females and growth rates of pouch young were positively related to sporocarp production. These observations suggest that hypogeous sporocarps are a primary food resource of high value to this marsupial.