Melissopalynology and the forage plants of the stingless bee Heterotrigona itama in Belitung, Indonesia

Melissopalynology could determine the types of pollen found in honey, which reflect the diversity of plant species used as forage plants for the bees around the meliponary areas. This study aims to analyze the diversity of forage plants used by Heterotrigona itama reared in meliponary located in areas with different land use types and surrounding vegetation, based on melissopalynology and vegetation survey. In this study, 18 honey samples were collected from meliponaries located at different villages in Belitung and East Belitung. The pollen in the honey samples was extracted, processed with the acetolysis method, and made as microscopic slides. Pollen types were counted, identified based on morphological features, and grouped into frequency classes. Vegetation analysis was carried out using the nested plots that placed following the dominant flight direction of the bees. We found 50 pollen types from 31 plant families in honey samples; the Myrtaceae is the most represented family. The forage plants used by H. itama were mainly trees, followed by shrubs and herbaceous plants. The predominant pollen types observed in honey were Acacia mangium, Cyperus sp., Ilex cymosa, Mangifera indica, Melastoma malabathricum, Rhizophora mucronata, and Syzygium urceolatum. The richness of pollen types in honey varied from 10 to 23 species in the meliponaries. While, the richness of plant species in the surrounding vegetation of the meliponaries ranged from 16 to 34 species. We found that the predominant pollen type in honey does not always correspond to the dominant plant species around the meliponaries. The cluster analysis based on the composition of pollen types in honey resulted in a grouping of meliponaries that was consistent with the clustering based on the composition of surrounding vegetation.