Ants may play the role of secondary seed dispersers and have superior dispersion effects when compared to vertebrates. Hirtella glandulosa Spreng, Buchenavia tomentosa Eickler and Simarouba versicolor A.St. Hil are arboreal species with a wide distribution in the cerrado and are of great economic and ecological importance. The objectives of this work were to study the interactions of the ant-cutter Atta sexdens with the fruits/seeds of H. glandulosa and B. tomentosa. Further, it was evaluated the dispersion of H. glandulosa and S. versicolor species by Atta sexdens in a forest remnant area of cerrado sensu stricto, as well as dispersion influence on the spatial distribution of the tree species using the Ripley K function. The study was conducted in an area of APP (permanent preservation area) on the experimental farm at the Federal University of Tocantins, Campus de Gurupi - TO in the southern state of Tocantins. Seeds were collected where interactions were observed between the leaf-cutting ants and the seeds of the two tree species to evaluate the effect of the ant on the germination of the tree seeds. The experiment consisted of three treatments: no cleaned by any method (T1), cleaned manually (T2) and cleaned by A. sexdens workers (T3). The percentage of germination and germination speed index (GSI) were evaluated. Areas of occurrence of the species S. versicolor and H. glandulosa and nest of the leaf-cutting ants were selected for the analysis of the spatial distribution. The results of the tests showed that A. sexdens performs the secondary dispersion of H. glandulosa and B. tomentosa. Removal of the pulp from the seeds by the ants increased the percentage and the rate of germination of both tree species. The predominant spatial pattern for the two tree species H. glandulosa and Simarouba versicolor was the aggregate pattern, i. e., the trees are arranged in groups within the area. This information is fundamental to understand the dynamics of the plant populations, for descriptive inventories and analyzes of biodiversity.
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