Atividade de colônias de Cornitermes Cumulans (Isoptera, Nasutitermitinae) sobre estruturas edáficas macro e microagregadas em casa de vegetação

Abstract

The aim of this paper is to present the termite impact on sampled soil structures during a controlled experiment. The structures used were sampled in a red yellow Latosol. The Cornitermes cumulans colonies were sampled in the same site and were maintained in controlled conditions during 9 months. Two types of structures were tested: dense macrostructures and a strong granular structure sampled in the same site than the colonies. Two replicates of the conceptual termite-structure model were developed. Two pots, one of them with the colony and food material, the second with the same structured material and food, composed each replicate; a tube associated the two pots. Macro and micromorphological descriptions were done, the distribution and localization of galleries were described and compared with those sampled at field. The termites' colonies maintained their exploring and construction activities, during the period, with some restrictions. In the experimental model with dense macrostructures the activities were important and equivalent in all of the volumes. But, in the experimental model with the strong granular structure the activities were essentially done in the volumes with the mounds. The new structures that were built, soil particles were oriented, and formed rigid walls as they were observed in field samples. C. cumulans colonies explored the volume aleatory in all directions. Many of the dense structures offered in the pots to the termite activity were completely or partially modified; the dense structure organic matter concentration were increase in the structures sampled in deep soil horizons. It was clear that the termites transformed structures offered, and that there created new microstructures and aggregates.