Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Herbivorous insects frequently fluctuate numerically throughout the year in response to variation in the availability and quality of plant resources. Here, we investigate the phenological relationship between the butterfly E. bechina and its host plant C. brasiliense in the Brazilian cerrado savanna. Abundance of E. bechina immature stages followed the temporal pattern of leaf production by the host plant, with increased numbers in the beginning of the rainy season (September-November). Ant visitation to extrafloral nectaries of C. brasiliense also increased in the humid period, following the production of new leaves and flower buds. Ant abundance, however, apparently had no major effect on the temporal occurrence pattern of Eunica immatures on host plants. Nevertheless, recent data on antagonistic and mutualistic ant-butterfly interactions have revealed that ants do affect host plant choice by butterflies in the ant-rich cerrado savanna. Future investigation in insect seasonality in cerrados should take into account not only climate and plant phenology, but also direct and indirect effects at the ant-plant-herbivore interface.472111118Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundo de Apoio ao Ensino, a Pesquisa e a Extensao (FAEPEX) of the Universidade Estadual de CampinasFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [04/05269-9, 11/50225-3, 2008/54058-1, 2011/18580-8]CNPq [300282/2008-7, 563332/2010-7]CNPq [301853/2009-6]