With the objective of to identifying the leaf-cutting ants that occur in the Depressão Central Region of Rio Grande do Sul State, Brazil, to verify its predominance species and its geographical distribution, a survey was done in 51 counties. Forty ant samples were collected in each county in second semester of 1999. Ants identification and data interpretation were carried out in the Fitossanidade Department of "Eliseu Maciel" Agronomy Faculty of the Federal University of Pelotas. Ants from 2.058 samples were identified, being observed: Atta sexdens piriventris Santschi, 1919; Acromyrmex laticeps (Emery, 1905); Acromyrmex crassispinus (Forel, 1909); Acromyrmex heyeri (Forel, 1899); Acromyrmex lundi (Guerin, 1838); Acromyrmex ambiguus (Emery, 1887); Acromyrmex striatus (Roger, 1863); Acromyrmex lobicornis (Emery, 1887); Acromyrmex coronatus (Fabricius, 1804) and Acromyrmex landolti balzani (Forel, 1884). The predominant species were Acromyrmex lundi, Atta sexdens piriventris, A. ambiguus, A. heyeri, A. striatus and A. laticeps, representing, respectively, 23.91%, 22.89%, 16.86%, 14.04%, 6.85% and 6.70% of total samples in this region, occurring in 84.31%, 60.78%, 70.59%, 84.31%, 78.43% and 88.24% of the counties, respectively. The others species (A. crassispinus, A. lobicornis, A. landolti balzani and A. coronatus) are less frequent, representing together 6.27% of total samples, being considered of rare occurrence in this region.
Acromyrmex; Atta; zoogeography; quenquén; saúva
