Consumption of arbuscular mycorrhizal fungi by spiny rats (Proechimys semispinosus) in eight isolated populations

摘要

The consumption of arbuscular mycorrhizal fungi (AMF) by Proechimys semispinosus (Central American spiny rat) was assessed via microscopic examination of faecal material for the presence of AMF spores. Mycophagy (indicated by the presence of spores)was compared among individual spiny rats residing on 8 isolated hilltop islands in Gatun Lake, Panama, during January and July 1996, islands being covered with tropical moist forest. Spores and sporocarps of Sclerocystis coremioides and spores from at least 4 species of Glomus were present in 77% of the 231 faecal samples examined. The proportion of faecal samples that contained AMF spores did not differ between spiny rat sex, age classes or months of sampling or with island area. However, there was apositive relationship between the proportion of samples containing spores and rodent density in January, and a significant positive trend in July. It is suggested that increased consumption of AMF on islands that supported high densities of spiny rats may have resulted from increased competition for primary food resources (fruits and seeds).