<b>Architecture of nests of <i>Acromyrmex</i> (<i>Moellerius</i>) <i>balzani</i> (Formicidae: Myrmicini: Attini) in pasture</b>

Abstract

Leaf-cutter ants Acromyrmex (M.) balzani (Emery), specialized in the cutting of gramineae are very common in pastures and agricultural crops of the South West of Bahia, with high density of nests. The objective of this work was to study aspects of nest architecture of A. balzani, located in pastures in the Southwest of Bahia, in order to search for the improvement of pest control strategies. Ten nests located in the cities of Vitoria da Conquista, Itapetinga, Tremedal and Itambé, BA were selected for study. Externally, the area, the volume of loose soil and the distance between the mount of loose soil and the tower were evaluated. The excavation was complete, opening gutters and cuttings in the soil profile. Afterwards, the measure of the height, width, depth, and the chambers height, regarding to the soil surface and to the coordinates of an orthogonal axis previously established were performed. The area and volume varied from 325 cm2 to 1880 cm2 and from 0.15 L to 5.88 L respectively. The distances between the loose soil mount and the tower varied from 2 to 37 cm. The total number of chambers per nest varied from 3 to 14, predominantly of chambers containing fungus, adult ants, and young forms. The higher concentration of chambers was at the first 30 cm and near the soil mount, but not under its projection.