Ant-nest distribution in a remnant of tropical rainforest in southeastern Brazil

Ant communities are generally extremely interactive, and competition betwee n ant species seems to be widespread. This characteristic of ant communitie s tends to produce a uniform pattern of nest distribution. In this study, w e aimed to test the nest distribution pattern, putting forward hypotheses t o explain the pattern. Nest mapping was carried out by delimiting ten one-s quare-meter quadrats, randomly located in a remnant of tropical rainforest in Vigosa, Brazil. In each quadrat, the nests were surveyed in the litter a nd surface soil up to 3 cm deep. A total of 295 nests from 41 ant species w ere collected in the ten quadrats. The pattern of nest distribution in the whole forest was aggregated, while the species showed a random distribution . The pattern of nest distribution inside each quadrat was also aggregated. The presence of species, such as Brachymyrmex sp., and Hypoponera sp.(4), with high nest densities suggests the occurrence of nest budding. This may be the reason for the aggregated nest distribution. Another explanation for this apparent aggregation is species specialization in a patchily distribu ted habitat. The results suggest that competition is not an important proce ss in the regulation of soil and litter ants distribution and, consequently , in the regulation of species richness in the studied area.