Serviços de polinização por abelhas no tomateiro (Solanum lycopersicum L., Solanaceae): a importância da conservação de áreas naturais e do manejo dos cultivos

Abstract

Landscape changes resulting from intensive land use, with consequent loss of habitat and fragmentation, and heavy metal contamination are considered major threats to bees and pollination services provided by them. The overall goal of this study was to evaluate pollination services provided by bees in open tomato crops, seeking to verify factors that influence the presence and maintenance of these pollinators in tomato crops and possible causes of their decline. The research was conducted in 10 commercial tomato fields located in the Triângulo Mineiro region (Southeastern Brazil). It was evaluated: abundance and species richness of flower visiting bees; their pollen collection behavior in flowers; the surrounding landscape of tomato crops and crop management; quality of fruits resulting from the additional pollination performed by bees, in general, and exclusively by species that do not perform buzz pollination; and heavy metals concentration in Apis mellifera foragers that visit tomato flowers. A total of 2330 bees belonging to 24 species were sampled. Areas of native vegetation around crops and association with other flowering crops positively affected bee visitation rate and species richness, showing the importance of conservation of natural vegetation remnants and of management type of tomato crop. Fruits with more seeds, larger and heavier were produced with visits of bees in flowers, reinforcing the relevance of pollination services provided by them in tomato, and species that do not perform buzz pollination showed to act as pollinators. The average concentrations of heavy metals found in A. mellifera were high, indicating that agricultural practices can be determinant in the degree of contamination by these elements in bees that visit tomato flowers. All of these results highlight the importance of bee diversity and farmers' awareness of the adoption of pollinator friendly practices.