Biomassa e carbono forrageados por Atta laevigata (Hymenoptera: Formicidae) em eucaliptais no Cerrado

Abstract

Eucalyptus plantations in Brazil have been growing in recent years, as they are raw materials for products of great global importance, such as cellulose, paper and energy. These plantations are also important for carbon storage, encouraging the market for carbon credits by companies and governments. However, wood production and carbon storage expectations can be compromised by insect pest herbivory, with emphasis on leaf-cutting ants. Many studies have addressed the role of these ants on wood production, but few have linked them to carbon foraging and its relationship to the climatic factors of the Cerrado biome, where most Brazilian eucalyptus is cultivated and the occurrence of Atta laevigata, one of the most economically important species for eucalyptus, predominates. Understanding this relationship is important to know the role of these herbivores in the accumulation of carbon in plants and soil and their contribution to the greenhouse effect. Therefore, the objective of this work was to evaluate how the temperature and relative humidity of the air influence the foraging of carbon biomass by Atta laevigata in eucalyptus in the Cerrado biome. The work was divided into three chapters. The first reviewed the role of leaf-cutting ants at each stage of the carbon cycle in the plant and soil. The second evaluated how the temperature and relative humidity of the air influence the foraging activity of A. laevigata in different seasons of the year in eucalyptus plantations. The third estimated the biomass and carbon foraged by leaf-cutting ants, depending on the temperature and air humidity in eucalyptus trees in the Cerrado. The results allowed to conclude that the foraging activity is predominantly daytime in three seasons, contrary to what is reported, being more intense in temperatures between 15 to 26°C and relative humidity between 66 to 80%. The accumulation of dry biomass and carbon varies throughout the year, with greater value in the summer and less in the spring. The annual amount of carbon foraged by a single active trail from a 72.87 m² Atta laevigata nest was 17 kg of carbon, corresponding to the amount of stored carbon of 6.96 trees per year.