Within the amazon region 130 species of stingless bees can be found, grouped into 26 genera, where Melipona and Trigona are the most represented. In Acre there is official record of 20 genera and 64 species of stingless bees, among those M. eburnea is one of the members, being very common in the Acre forests and rationally created by melipolinculturists, in the municipality of Rio Branco. The objectives that integrated this job were: (i) to identify botanical species used by M. eburnea to collect pollen and nectar; (ii) to determine the frequency of pollen types found in honey itself as well as in the pollen charges of the bees´ corbicles of M. eburnea; (iii) to point out the flowering seasonality of the plants used by M. eburnea to collect pollen and nectar; (iv) to identify the growth habits of M. eburnea´ s pollen and nectar suppliers; (v) to indicate the contribution of native, cultivated and ruderal species in the supply of pollen and nectar to M. eburnea; (vi) to verify the influence of rainfall and light intensity on the supply of food resources for M. eburnea, throughout the year; (vii) to assess the protein content and the specific concentration of amino acids content in the pollen collected by M. eburnea, throughout the year and (viii) to check if there is a link between the different levels of protein and amino acids with the diversity of pollen types collected by M. eburnea. Once a week, from April 2017 to March 2019, from 5 am to 9 am. worker bees from three colonies of M. eburnea have been sampled. The weekly samples have been gathered, thus creating a single monthly sample. The pollen sources used by M. eburnea have consequently been determined by sampling the pollen loads from the worker bees, when returning to the colony with pollen in their corbicles. The sources of nectar have been confirmed by checking on honey samples taken from the pots, still open. In order to quantify the protein content and the amino acid profile, the samples have been collected together with those of pollen and honey, in still open pollen pots and from the same selected colonies. After that, pollen has been collected and sampled from plants present in the study area, as well as from the dried ones, kept in the UFAC – UFACPZ herbarium, to preparing a reference “pollen library”. Microscopy slides have been set to perform qualitative and quantitative analysis of the pollen types contained in the samples of the bees´ charges, honey and pollen pots. Palynological analysis have shown that M. eburnea bees have harvested floral resources from 115 botanical species, belonging to 47 families and 96 genera: 61 species have been used both to collect pollen and nectar, 19 only for pollen collection and 35 just for nectar extraction. Fabaceae (Mimosoideae) and Myrtaceae
have been the main sources of pollen and nectar to M. eburnea, in all the seasons of the bee calendar (rainy, rain-dry transition, drought and dry-rain transition). Among the pollen types of the corbicle loads´ samples, Mimosa pudica represented the highest concentration 6.79 (log 10). When considering the volume of the pollen grain, Hybiscus was the most important. Among those classified in the honey samples, Crotalaria retusa obtained the highest concentration of 6.56 (log 10). In the main group of plants visited by M. eburnea, 50.61% were native; 36.59% cultivated and 12.81% ruderal. Referring to the habit, 40.25% were trees; 34.59% bushes; 13.21% herbs; 8.18% vines; 3.14% sub-shrubs and 0.63% epiphytes. The seasonality of the botanical species utilized by M. eburnea to collect floral resources has demonstrated wide variation throughout the study period: the pollen types Solanum and M. pudica have turned out being the least seasonal, in the corbicula loads´ samples. Among honey ones, Combretum. These pollen types have been present during the all assessed months. 13 amino acids have been found in the pollen stored by M. eburnea, nine of which are essential ones. In this group, Arginine was preponderant. Among the non-essentials, Proline has shown the highest concentration, being predominant in the set of identified amino acids as well, representing 68.5%. The levels of raw protein vary from 16.57 to 24.39%, within an average of 20.75%. The highest concentration of flowering has occurred in the dry season, characterized by a decrease in the volume of rainfalls and an increase in the amount of hours of sunshine. As for the totality of plants visited by M. eburnea, 38.39% offered pollen and/or nectar, during the dry season. It is concluded that (i) M. eburnea presents a generalist behavior in the use of pollen sources; (ii) the main sources of pollen and nectar for M. eburnea have been Fabaceae and Myrtaceae; (iii) native vegetation, mainly trees and bushes, have been the primary source of pollen and nectar for M. eburnea; (iv) an association among native, cultivated and ruderal plants provides appropriate amounts of proteins and amino acids for M. eburnea.
Keywords: Stingless bee, Rational breeding, Meliponiculture, Floral resources, Agroforestry system – AFS.