Foraging of Honeybees from Different Ecological Areas Determined through Melissopalynological Analysis and DNA Metabarcoding

Abstract

The environment significantly impacts the lives of bees and their feeding. This study aimed to investigate bee foraging using melissopalynological analysis and DNA metabarcoding in intensive farming, reserved, and urbanized areas. The highest alpha diversity was observed in the reserved and intensive farming areas. The urbanized area had less diversity. In the intensive farming area, Sinapis, Helianthus, and Fagopyrum predominated; in the reserved area, Melilotus, Helianthus, and Brassica predominated. In the urbanized area, garden plants, namely radish (Raphanus sativus) and cucumber (Cucumis hystrix), and agricultural plants, namely soybean (Glycine max) and melon (Cucumis melo), were often found. The most significant agreement was between the rbcL and the melissopalynological analysis. The ITS2 revealed equal matches with both rbcL and melissopalynology, but this marker missed or underestimated some genera. Trifolium pretense and Brassica nigra were identified simultaneously by the melissopalinology method and two genetic markers in DNA metabarcoding. The species Convolvulus arvensis, Melilotus officinalis, Echium vulgare, Brassica rapa, Helianthus divaricatus, and Onobrychis viciifolia were found in all ecological areas. Imperfect databases impose some limits in the identification of some taxa using metabarcoding. The further research and expansion of plant databases is needed. Studying the food preferences of bees in different environmental conditions and landscapes is necessary to develop measures to preserve their populations.