Contribution of the cerrado as habitat for sunflower pollinating bees

Abstract

Agricultural landscapes sometimes include natural habitats which can support the ecosystem by enhancing the pollination of crops, thus boosting the productivity. This research was conducted between May and July 2017, in the municipality of Tangará da Serra, Mato Grosso, Brazil, to assess the Cerrado from the perspective of it being a crucial habitat to sustain the sunflower-pollinating bees (Helianthus annuus L.). The bees were sampled using entomological nets and pan traps, in specifically marked out plots (20 m x 150 m), in the Cerrado, and in a sunflower crop, at different distances from the Cerrado border. The assessment was done in terms of the composition and species richness, abundance of individuals and the mass (g) of the sunflower chapters exposed and isolated from the floral visitors. While species richness showed no differences between the Cerrado and sunflower crop, a difference was observed for abundance, with more numbers of individuals in the sunflower crop, most likely because of the food source supply. In the sunflower crop, the bee diversity decreased proportionally as the distance from the border increased. The seed mass of the sunflower chapters was significantly higher in the flowers open to visitors than in those of the isolated chapters open for visitation. From the results, it was evident that the bees present in the Cerrado visit the sunflower crop to gather pollen and nectar, and thus assist in cross-pollinating them and raising the productivity.