Antagonismo de bactérias endofíticas de plantas da Amazônia contra o jardim de fungos associados às formigas cortadeiras Atta sexdens Hymenoptera (Formidae: Attini).

Abstract

Among the species of known insects (approximately 900 thousands), at about 2% is considered eusocial, because they live in truly advanced societies. The leaf-cutting ants belong to eusocial insects group and reached the major level of the instinct through the cultivation of fungi. Nowadays, they seems to be the unique animal group that have developed an advanced agriculture, based on their symbiosis with fungi, that appeared at about 50 million years ago, long before human being had appeared and become cultivator. Cutting leaves that serves as substrate to fungi cultivation for feed, ensure a high economic value to leaf-cutting ants, especially when they compete with men. So, the aim of this work was to perform a study about the microorganisms communities associated to the fungi garden of the leaf-cutting ants, Atta sexdens, evaluating the possibility to control them by the antagonistic activity of endophyte microorganisms from Amazon plants. To enable these assays, 13 leaf-cutting ants colonies (at about 5 monts of age) containing all classes (queen, soldiers, males and workers) were collected and transferred to the Laboratório de Microrganismos LABGEMMA of the Universidade Federal do Amazonas UFAM. From these anthill, associated microorganisms were isolated, cultivated, identified (by molecular and classical methods) and preserved at appropriated conditions. The antagonisms assays were performed by the method of paired culture, using endophytic microorganisms as inhibitors of those anthill associated. In vivo assays were performed with lab assembled anthills, to evaluate the potential for biological control against them. The main isolated and identified anthills associated microorganisms were: Leucoagaricus gongylophorus; Bionectria ochroleuca; Aspergillus flavus; Trichoderma longibrachiatum; Fusarium solani, yeasts and gram positive and gram negative bacteria. Antagonisms assays against L. gongylophorus, T. longibrachiatum, A. flavus and one of the anthill yeasts were promissing as an alternative method to the anthills biological control.