ATTA VOLLENWEIDERI (HYMENOPTERA: FORMICIDAE) IN A NATIVE FOREST FROM THE NORTH CENTRE OF ENTRE RÍOS

Abstract

Leafcutter ants constitute a severe problem in native forests from the province of Entre Ríos. Previous studies reveal that the presence of the genera Atta and Acromyrmex causes damage to the ground cover and foliage in tree species. A survey on ant colonies of the genus Atta was carried out at the facility named El Carayá (Feliciano, Entre Ríos) in order to identify and describe the species, and classify their nests. A transect of 300 m (L) x 100 m (W) was marked. The nests placed in it were described. Samples of entomological material were collected; genus Atta vollenweideri Forel, 1983, was identified as the single specie within the transect. This ant specie builds conical nests with an apparent area of loose soil and no vegetation on the surface. The average nest values were the following: 48.72 m 2 (area); 20.15 m 3 (external volume). 15 active entrance holes and 14 ant tracks were observed, the latter being 39.47 m (length) and 0.0674 m (width). Active entrance holes (38.93 %), the number of ant tracks (41.53 %) and their length (42.44 %) were the values with the highest variation ranges.