Fenologia e insetos visitantes de três espécies arbóreas de vegetação secundária no município de Bragança, estado do Pará

Abstract

The flowering and fruiting phenology is considered an important biological event because it contributes to the perpetuation mechanisms of the species and to natural selection. The objective was to describe the floral morphology, characterize the flowering and fruiting phenology and identify the flower-visiting insects in three tree species occurring in secondary vegetation. The research was carried out in the Benjamin Constant community, municipality of Bragança, northeastern Pará state, from August/2001 to May/2002 with the species Croton matourensis Aubl.,Platonia insignis Mart. and Tapirira guianensis Aubl. in the proportion of 20, 10 and 20 individuals/species, respectively. For floral morphology, inflorescences and flowers were collected and described using a magnifying glass. The phenology was monthly with the aid of binoculars and two observation towers built of wood, where the following parameters were observed (flowering = appearance of floral buds + open flowers; fruiting = immature fruits + mature fruits). Visiting insects were collected for identification purposes in family, genus and species at the Museu Paraense Emílio Goeldi Zoology Laboratory. The results showed that Croton matourensis Aubl.is monoecious with terminal inflorescence, simple pluriflora of the amento type, with pedicellate, cyclic and unisexual flowers; flowering and fruiting from March to April; the insect visitors of the orders Hymenoptera and Diptera. Platonia insignis Mart. is hermaphrodite with terminal, acyclic, pentamerous flower with pinkish petals; it flowered from August to September and fruiting from September to February; the insect visitors of the orders Hymenoptera. Tapirira guianensis Aubl.is dioecious, with terminal, compound pluriflora, racemes cluster-like inflorescence with unisexual flowers and yellow petals; it flowered from October to January and set fruit from January to February; the visiting insects of the order Diptera. All species showed asynchronism in flowering and fruiting.