Pollen assemblage variability of Apis mellifera honeys (Diamante, Entre Ríos, Argentina)

Abstract

Abstract The pollen assemblage of 27 honey samples produced by Apis mellifera from three apiaries in the Diamante department, Entre Ríos (Argentina) were analysed. The study area is highly anthropised with cereal, oilseed and forage crops. The samples were obtained sequentially over four apicultural seasons (1999–2000; 2000–2001; 2001–2002; 2002–2003). In each season, one to three honey extractions, corresponding to the initial (I), middle (II) and final (III) productive periods, were made. Pollen assemblage of the honey reflected the study area vegetation. Monofloral honey were exclusively from exotic species, mainly of the dominant crops. Monofloral honey of Lotus corniculatus, Melilotus albus, Medicago sativa, Ammi, Glycine max and ‘clovers’ were obtained. The monofloral honey corresponded to 87.5%, 50% and 66%, respectively, to the honeys obtained in each productive period over the four apicultural seasons. The intra-annual variation of the samples responded to the phenology of the plant species. The inter-annual variations were associated with differential foraging, and the amount of precipitation during the apicultural period. Significant variations were observed when each apiary is compared to itself in different apicultural seasons, and in identical productive periods. Apis mellifera used a fraction of the available flora as nectar resources. The number of plant species visited remained relatively constant throughout the productive periods although it was higher during the apicultural seasons with lower rainfall.