Resumo

TONHASCA, Athayde  e  LIMA BRAGANCA, Marcos Antonio. Forager size of the leaf-cutting ant Atta sexdens (Hymenoptera: Formicidae) in a mature eucalyptus forest in Brazil. Rev. biol. trop [online]. 2000, vol.48, n.4, pp.983-988. ISSN 0034-7744.

We determined the size characteristics of foragers of the leaf-cutting ant Atta sexdens in a mature eucalyptus forest in Campos dos Goytacazes, Rio de Janeiro State, Brazil, at daytime (7: 30 to 10: 00 hr) and nighttime (19: 00 to 23: 00 hr). There were no significant differences between daytime and nighttime ant mass (M_a), but leaf fragment mass (M_l) and burden (B = [M_a + M_l]/M_a), which indicates relative load capacity, were significantly greater at daytime. There was a positive linear relationship between M_a and M_l for the combined daytime and nighttime data, and increases in M_a resulted in lower B. We compared A. sexdens characteristics with published results for Atta cephalotes, a closely related species. A. sexdens is larger and therefore able to carry heavier loads, but its burden is about 72% of the average value for A. cephalotes. We suggest that the lower load capacity of A. sexdens in comparison to A. cephalotes is related to its relatively larger size.

Palavras-chave : Atta sexdens; Atta cephalotes; ecology; foraging; leaf-cutting ants.