Biologia reprodutiva de Anacardium giganteum W. Hancock ex Engl. – cajuaçu ocorrente no município de Bragança, Pará.

Abstract

The reproductive biology of Anacardium giganteum W. Hancock ex Engl. present in Bragança, district of Pará state, was evaluated and described through its phenology study, morphological and inflorescence description, evaluation of the flower activity and its registration, identification and evaluation of its main flower visitors and entomofauna identification and description along with the damages caused by it to the cajuaçu flowers and leaves. The Phenology was evaluated through monthly observation of 20 trees. The absence or presence of reproductive and vegetative phenophases of the species were recorded relating them to rainfall and temperature variables. Morphological and Inflorescence variable characteristics were measured and counted. Flower activity verification was performed through the close observation of 30 flowers. During the observation hours, changes to the color and stigma position were registered. Flower visitors were evaluated through watch towers. Each species behavior was registered in order to determine the possible pollinator along with its occurrence frequency and relative abundance which were calculated. Entomofauna was identified through the absence or presence of damages to the inflorescence and to the flowers. During the observation time, the species presented mature leaves and different peaks of foliage and defoliation activity. Foliage presented the highest peaks two months at the same time as the fruiting, which coincided with the rainy season. The studied phenophases showed significant correlation with climatic variables, which enables us to say that the species present seasonality in the phonological events. As for the floral biology, the species is andromonoic and the flowers it present variation in the number of fertile stamens and in the number of petals was found. As the diurnal flower anthese process developed, changes in the stigma position and stamen happened. Respectively, the hermaphrodite flower (not fertilized) and the male flower lasted about 72 and 24hours, both of which showed a color change to red wine. There were 2,876 flower visitors observed. On average, the number of visitors was 230,40 per inflorescence per tree during the 12 hours (6 am to 6 pm) of observation. 28 species belonging to 13 15 families distributed in four orders were identified among the visiting insects, being the bee group it was the most important one and the responsible for the pollinization of cajuaçu, maybe, the cajuaçu inflorescence and leaves presented very damages and the entomofauna associated with these damages it was amounted to six species distributed in six families in four orders. The frequency of occurrence of the entomofauna varied among tree sampled. Only the Cecidomyiidae e Oecophoridae families presented 100% of the frequency. The occurrence of damages caused by this entomofauna must be taken into account when adopting the planting system.