The floral biology and pollination of Clusia arrudae was studied at "Serra da Calçada". C. arrudae does not present apomixis even when resin is deposited on the stigma. Fruits developed from flowers manually pollinated produced more seeds (6.3 per locule in average) than fruits developed from flowers naturally pollinated (4.3 seeds per locule). Blooming of C. arrudae peaks between December and mid-February. Male and female individuals of C. arrudae produce flowers daily; however, each three days there is a synchronized anthesis peak within the population. Sexual rate in the population is 1:1, with male plants producing more flowers than female. Male flowers produce about 11 × 10(6) pollen grains along the three day anthesis. Most of them (about 66%) are presented on the first day. The stigmas of female flowers remain receptive for three days or four days when pollination does not happen in the first three days. Flowers of C. arrudae were visited by six species of bees for pollen or resin collection. Workers of Apis mellifera and Trigona spinipes, and females of Xylocopa frontalis and Neocorynura sp. visited male flowers for pollen; workers of Trigona spinipes also visited female flower for resin collection. Workers of Melipona quadrifasciata and females of Eufriesea nigrohirta were observed collecting resin on both male and female flowers. Due to its frequency and behavior on flowers of both sexes, E. nigrohirta is the main pollinator of C. arrudae at "Serra da Calçada".
Clusia arrudae; Eufriesea nigrohirta; floral biology; pollination
