Biologia floral, fenologia reprodutiva, entomofauna e valor econômico dos serviços ecossistêmicos realizados pelos polinizadores de Campomanesia adamantium (Cambessédes) O. Berg – Myrtaceae em área de cerrado no sul do Mato Grosso do Sul - Brasil

Abstract

Campomanesia adamantium (Cambessédes) O. Berg, belongs to the Myrtaceae family popular known as guavira, gabiroba, etc. It’s a shrub usually found in bushes, with tiny flowers of whitish cream colour, in rural physiognomy of Cerrado and in typical Cerrado, being abundant in the State of Mato Grosso do Sul. This current study has as an objective evaluate C. adamantium, its reprodutive system, phenological events, floral biology, behavior of foraging of the floral visitors, trying to identify the effective polinizator and the valuation of ecosystemic services accomplished by the bees. The captured ones were developed during the full bloom period, in the first 15 minutes of each hour, between 06h00min and 18h15min, in different plants of C. adamantium, randomly defined. The other 45 minutes, was evaluated the visitors behavior, in an indefinite number of flowers of other 10 plants. The floral visitors were killed in deadly chamber with ethyl acetate, separated in relation to the collection period, transported to the Laboratório de Apicultura (LAP), of the Faculdade de Ciências Biológicas e Ambientais (FCBA) of the Federal University of Grande Dourados-MS (UFGD), prepared and identified with the help of specialized literature, or specialists. To evaluate the guavira reprodutive system, were developed tests of controled pollination, envolving xenogamy, geitonogamy, apomixia, manual autopollination, spontaneous autopollination and the control (natural pollination). Mounthly, were recorded the presence and absence of phenophases of budding, deciduous, buttons, flowers and fruits in a population of 25 individuals. 200 buttons were marked to evaluate the valuation/productivity of the pollinators, divided by five groups of 40 being: Evaluation of free pollination (controled) (T1), by Apis mellifera (T2), by native bees (T3), Autopollination (T4) and Pollination by the wind (anemophily) or another non identified agent (T5). The valuation was calculated by the methodology of proportion of dependent prodution of the pollinator, submiting the results to the analysis of variance (ANOVA) and the test of Tukey. Production in average 42.6 ± 14.15 was observed floral buttons per inflorescence. The anthesis is of morning occurrence around 5h00min, establishing the receptive stigma until 13h00min. All the development process, from the flower opening (anthesis), to the presence of ripe fruits, had an average duration of 63 days. The offered resources to the visitors were the pollen and the nectar (in small amount). The fruit-flower reason was of 0.66, representing a low energetic cost in the reproductive process, ensuring the significant amount of fruits. The species showed auto-incompatibility, requiring the pollinators for a considerable fruit production. The predominant reprodutive system was the xenogamy, effectively performed by bees. 31 species of visitors were shown in the following order: Hymenoptera (79.30%), Coleoptera (11.34%), Diptera (9.1%) e Hemiptera (0.24%). Among the group of hymenoptera, three species were considered ruling, being: he A. mellifera africanized, Brachygastra sp. (wasp) and Trachymyrmex sp. (ant). The bees A. mellifera stood out as the effective polinizators representing 53.24% of collective visitors. The greatest amount of wasps, ants and some coleoptera were associated to the activity herbivory of the floral tissues. The best rates of fruiting happened during the treatments in which the plant had direct contact with the bees, making no difference statisticaly between the other treatments. The abortion of fruits was observed, which can have as a cause, the climate phenomena or other factors, as the herbivory. 245.44 fruits/Kg were related with the medium costs of R$ 8.63 the kilo in the informal market. The value of the services done by the A. mellifera was of R$ 4.32/Kg and the native bees, around R$ 4.31/Kg. Close values which demonstrates the importance of the bees to the effective production of the guavira.