YEAST COMMUNITIES OF THE CACTUS PILOSOCEREUS-ARRABIDAE AND ASSOCIATEDINSECTS IN THE SANDY COASTAL PLAINS OF SOUTHEASTERN BRAZIL

The yeast communities from necrotic tissues, decaying flowers and frui ts, and from larval feeding sites of the moth Sigelgaita sp. in the ca ctus Pilosocereus arrabidae were surveyed in three restinga ecosystems in Southeastern Brazil. Insects associated with these substrates were sampled to verify the vectoring of yeasts. The cactus Pilosocereus ar rabidae was shown to have four different yeast communities associated with it. Necrotic stems had a diverse yeast community with the prevale nt species Pichia barkeri, Candida sonorensis, Pichia cactophila, Geot richum sp., Myxozyma mucilagina and Sporopachydermia sp. A, representi ng about 80% of the total isolates. Pichia sp. A and a Candida domercq ii-like species represented more than 90% of the yeast isolates from d ecaying flowers. Fruits had a heterogeneous yeast community with typic al fruit yeasts of the genus Kloeckera, basidiomicetous anamorphs of t he genus Cryptococcus, the black yeast Aureobasidium pullulans, Pichia sp. A, a Candida demercqii-like species, and some cactophilic yeasts, especially Clavispora opuntiae. The feeding site of Sigelgaita sp. la rvae had Clavispora opuntiae as the prevalent species. Insect vectors are suggested as one the most important factors influencing the compos ition of these yeast communities.