ABSTRACT Associations between ants and Hemiptera are common in the families Membracidae, Coccoidea and Aphidoidea, but there are only a few cases of ants using honeydew of Cicadellidae species. We surveyed plants of Roupala montana Aubl. (Proteaceae) in the cerrado area (savanna like vegetation) in the Federal District (Brazil) during the rainy season of 2006 and 2007. In this period the plants produce new leaves, which are consumed by the nymphs of a probable new species of Rotundicerus (Cicadellidae: Idiocerinae). The nymph groups are of variable size, with a mean of 20 individuals. We found 83% of them being tended by ants. A total of 21 ant species was documented, with predominance of Camponotus spp. and Cephalotes spp. There is a clear species turnover of ants on the nymph groups and attendance is not continuous in most of the cases, suggesting an opportunistic association between ants and Rotundicerus sp. Translation by the authors.