Submitted to: International Journal of Speleology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/15/2008
Publication Date: 1/1/2009
Citation: Nieves-Rivera, A.M., Santos-Flores, C.J., Dugan, F.M., Miller, T.E. 2009. Guanophilic fungi in three caves of southwestern Puerto Rico. International Journal of Speleology 38: 61-71. Interpretive Summary: Although there is a large literature on dung-inhabiting fungi, much less research has focused on bat guano in caves. Most of the latter literature has had the objective of documenting occurrence and frequency of fungi pathogenic to humans or animals. The present, wider study focuses on the biodiversity of fungi inhabiting bat dung in three caves of Puerto Rico. The fungus most commonly seen in bat dung incubated in vitro (moist chambers) was Circinella umbellata, a fungus previously recovered from mammal or reptilian dung world wide, including bat dung, and well represented in fungal germplasm collections. Other fungi, primarily microscopic but also some mushroom species, are listed. Several species are important for their mycotoxigenic potential or trophic roles in cave systems.
Technical Abstract: Fifty species of guanophilic (bat guano-loving) fungi were isolated from field-collected samples within three caves in south-western Puerto Rico; most were mitosporic fungi (23 species). The caves studied were Cueva La Tuna (Cabo Rojo), Cueva de Malano (Sistema de Los Chorros, San Germán), and Cueva Viento (El Convento Cave-Spring System, Guayanilla-Peñuelas). The most conspicuous fungus by far was the zygomycete Circinella umbellata (Mucorales). Circinella umbellata dominated the bat guano incubation chambers (Petri dishes lined with sterile filter paper moistened with sterile water) at ambient laboratory conditions. Nineteen species of basidiomycetes (e.g., Ganoderma cf. resinaceum, Geastrum cf. minimum, Lepiota sp., Polyporus sp., Ramaria sp.) and three species of ascomycetes (Hypoxylon sp., Xylaria anisopleura, and X. kegeliana) were also recorded. They were found on soil, rotting leaves, bark and rotting wood, buried in bat guano located below natural skylights or sinkholes.