INTERACTIONS BETWEEN FUNGUS-GROWING ANTS (ATTINI), FRUITS AND SEEDS IN CERRADO VEGETATION IN SOUTHEAST BRAZIL

We surveyed the material collected For fungus culturing by attine ants in the cerrado vegetation of southeast Brazil. Six genera of the so-c alled lower attines (Cyphomyrmex, Mycetarotes, Mycocepurus, Myrmicocry pta, Sericomyrmex and Trachymyrmex) collect a wide variety of plant ma terial as fungal substrate. Plant diaspores of nonmyrmecochorous speci es comprise a large portion of the items brought to the nest, especial ly in the rainy season. Removal experiments using fruits of selected p lant species revealed that attine ants (including the leaf-cutters Att a and Acromyrmex) not only actively clean the seeds (remove fruit pulp ), but also carry them up to 12 m in the cerrado. Germination tests sh owed that removal of fruit pulp by attine ants increases germination r ate in Ocotea pulchella (Lauraceae), Prunus sellowii (Rosaceae), Ourat ea specrabilis (Ochnaceae), Rapanea umbellata (Myrsinaceae) and Psycho tria stachyoides (Rubiaceae). For P. stachyoides, however, ants had no effect on germination if seeds had already passed the digestive tract of birds. Aril removal by attines also increases germination success of Copaifera langsdorffii (Leguminosae) and Virola sebifera (Myristica ceae) seeds. The results indicate that attine-fruit/seed interactions are particularly conspicuous in the cerrado, suggesting that fungus-gr owing ants may play a relevant role in fruit/seed biology in this vege tation type. potential ant-derived benefits to diaspores of nonmyrmeco chorous plants in the cerrado would include secondary seed dispersion and/or increased germination success by ant-handled seeds.