Multiple-scale spatial distribution of the fungal epiphyll Scolecopeltidium on Trichilia spp. in two lowland moist tropical forests
The leaf-inhabiting fungus Scolecopeltidium mayteni (Micropeltaceae) is common on Trichilia tuberculata in lowland tropical forests on Barro Colorado Island, Panama, and on Trichilia moritzii in Corcovado National Park, Costa Rica. The sexual reproductive structures (ascomata) of the fungus have a clumped or random distribution on leaflet surfaces. The density of ascomata correlates well with the density of hyphae on the leaf surface and is a good indicator of the intensity of fungal colonization. Most of the variability in colonization is at a leaf-to-leaf level rather than among leaflets or among plants. Intensity of fungal colonization is directly related to the light environment of the leaflet or plant, but not to the density of hosts. The Scoiecopeitidium–Trichilia system is well suited for studies on ecological factors affecting host–fungal symbioses in natural plant communities. Key words: Trichilia luberculata, Trichilia moritzii, Loculoascomycete, density dependence, Panama. Costa Rica.