Abstract
The densities of colonies of Acromyrex landolti and Atta laevigata were assessed on unimproved savannah and on two types of improved pasture at Ebini in Guyana. Hourly counts for 24h were made of the amount and nature of the vegetation being brought into selected nests, and it was concluded that A. landolti was almost exclusively a grass cutter, whilst 61 per cent of A. laevigata workers were cutting dicotyledons. Their importance as pests results from the physical nuisance of large Atta nests, from the destruction of newly planted grass stands prior to establishment, and possibly from their competition with cattle for grass (here tentatively assessed around four per cent on improved Paspalum notatum pastures). Control measures undertaken are briefly described.
